/[pcre]/code/trunk/doc/pcre.txt

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-revision 211 by ph10,
Thu Aug  9 09:52:43 2007 UTC
+revision 227 by ph10,
Tue Aug 21 15:00:15 2007 UTC
 Line 908 
 NEWLINES
         dard. When PCRE is run, the default can be overridden,  either  when  a
         pattern is compiled, or when it is matched.
+        At compile time, the newline convention can be specified by the options
+        argument of pcre_compile(), or it can be specified by special  text  at
+        the start of the pattern itself; this overrides any other settings. See
+        the pcrepattern page for details of the special character sequences.
         In the PCRE documentation the word "newline" is used to mean "the char-
-        acter or pair of characters that indicate a line break". The choice  of
+        acter  or pair of characters that indicate a line break". The choice of
-        newline  convention  affects  the  handling of the dot, circumflex, and
+        newline convention affects the handling of  the  dot,  circumflex,  and
         dollar metacharacters, the handling of #-comments in /x mode, and, when
-        CRLF  is a recognized line ending sequence, the match position advance-
+        CRLF is a recognized line ending sequence, the match position  advance-
-        ment for a non-anchored pattern. The choice of newline convention  does
+        ment for a non-anchored pattern. There is more detail about this in the
-        not affect the interpretation of the \n or \r escape sequences.
+        section on pcre_exec() options below. The choice of newline  convention
+        does not affect the interpretation of the \n or \r escape sequences.
  MULTITHREADING
-Line 1522 
 INFORMATION ABOUT A PATTERN
+Line 1528 
 INFORMATION ABOUT A PATTERN
         returned.  The fourth argument should point to an unsigned char * vari-
         able.
+          PCRE_INFO_HASCRORLF
+        Return 1 if the pattern contains any explicit  matches  for  CR  or  LF
+        characters,  otherwise  0.  The  fourth argument should point to an int
+        variable.
           PCRE_INFO_JCHANGED
         Return 1 if the (?J) option setting is used in the  pattern,  otherwise
-Line 1812 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1824 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
         tion of pcre_compile()  above.  During  matching,  the  newline  choice
         affects  the  behaviour  of the dot, circumflex, and dollar metacharac-
         ters. It may also alter the way the match position is advanced after  a
-        match  failure  for  an  unanchored  pattern.  When  PCRE_NEWLINE_CRLF,
+        match failure for an unanchored pattern.
-        PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a  match  attempt
-        fails  when the current position is at a CRLF sequence, the match posi-
+        When  PCRE_NEWLINE_CRLF,  PCRE_NEWLINE_ANYCRLF,  or PCRE_NEWLINE_ANY is
-        tion is advanced by two characters instead of one, in other  words,  to
+        set, and a match attempt for an unanchored pattern fails when the  cur-
-        after the CRLF.
+        rent  position  is  at  a  CRLF  sequence,  and the pattern contains no
+        explicit matches for  CR  or  NL  characters,  the  match  position  is
+        advanced by two characters instead of one, in other words, to after the
+        CRLF.
+        The above rule is a compromise that makes the most common cases work as
+        expected.  For  example,  if  the  pattern  is .+A (and the PCRE_DOTALL
+        option is not set), it does not match the string "\r\nA" because, after
+        failing  at the start, it skips both the CR and the LF before retrying.
+        However, the pattern [\r\n]A does match that string,  because  it  con-
+        tains an explicit CR or LF reference, and so advances only by one char-
+        acter after the first failure.  Note than an explicit CR or  LF  refer-
+        ence occurs for negated character classes such as [^X] because they can
+        match CR or LF characters.
+        Notwithstanding the above, anomalous effects may still occur when  CRLF
+        is a valid newline sequence and explicit \r or \n escapes appear in the
+        pattern.
           PCRE_NOTBOL
         This option specifies that first character of the subject string is not
-        the beginning of a line, so the  circumflex  metacharacter  should  not
+        the  beginning  of  a  line, so the circumflex metacharacter should not
-        match  before it. Setting this without PCRE_MULTILINE (at compile time)
+        match before it. Setting this without PCRE_MULTILINE (at compile  time)
-        causes circumflex never to match. This option affects only  the  behav-
+        causes  circumflex  never to match. This option affects only the behav-
         iour of the circumflex metacharacter. It does not affect \A.
           PCRE_NOTEOL
         This option specifies that the end of the subject string is not the end
-        of a line, so the dollar metacharacter should not match it nor  (except
+        of  a line, so the dollar metacharacter should not match it nor (except
-        in  multiline mode) a newline immediately before it. Setting this with-
+        in multiline mode) a newline immediately before it. Setting this  with-
         out PCRE_MULTILINE (at compile time) causes dollar never to match. This
-        option  affects only the behaviour of the dollar metacharacter. It does
+        option affects only the behaviour of the dollar metacharacter. It  does
         not affect \Z or \z.
           PCRE_NOTEMPTY
         An empty string is not considered to be a valid match if this option is
-        set.  If  there are alternatives in the pattern, they are tried. If all
+        set. If there are alternatives in the pattern, they are tried.  If  all
-        the alternatives match the empty string, the entire  match  fails.  For
+        the  alternatives  match  the empty string, the entire match fails. For
         example, if the pattern
           a?b?
-        is  applied  to  a string not beginning with "a" or "b", it matches the
+        is applied to a string not beginning with "a" or "b",  it  matches  the
-        empty string at the start of the subject. With PCRE_NOTEMPTY set,  this
+        empty  string at the start of the subject. With PCRE_NOTEMPTY set, this
         match is not valid, so PCRE searches further into the string for occur-
         rences of "a" or "b".
         Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe-
-        cial  case  of  a  pattern match of the empty string within its split()
+        cial case of a pattern match of the empty  string  within  its  split()
-        function, and when using the /g modifier. It  is  possible  to  emulate
+        function,  and  when  using  the /g modifier. It is possible to emulate
         Perl's behaviour after matching a null string by first trying the match
         again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then
-        if  that  fails by advancing the starting offset (see below) and trying
+        if that fails by advancing the starting offset (see below)  and  trying
         an ordinary match again. There is some code that demonstrates how to do
         this in the pcredemo.c sample program.
           PCRE_NO_UTF8_CHECK
         When PCRE_UTF8 is set at compile time, the validity of the subject as a
-        UTF-8 string is automatically checked when pcre_exec() is  subsequently
+        UTF-8  string is automatically checked when pcre_exec() is subsequently
-        called.   The  value  of  startoffset is also checked to ensure that it
+        called.  The value of startoffset is also checked  to  ensure  that  it
-        points to the start of a UTF-8 character. There is a  discussion  about
+        points  to  the start of a UTF-8 character. There is a discussion about
-        the  validity  of  UTF-8 strings in the section on UTF-8 support in the
+        the validity of UTF-8 strings in the section on UTF-8  support  in  the
-        main pcre page. If  an  invalid  UTF-8  sequence  of  bytes  is  found,
+        main  pcre  page.  If  an  invalid  UTF-8  sequence  of bytes is found,
-        pcre_exec()  returns  the error PCRE_ERROR_BADUTF8. If startoffset con-
+        pcre_exec() returns the error PCRE_ERROR_BADUTF8. If  startoffset  con-
         tains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.
-        If you already know that your subject is valid, and you  want  to  skip
+        If  you  already  know that your subject is valid, and you want to skip
-        these    checks    for   performance   reasons,   you   can   set   the
+        these   checks   for   performance   reasons,   you   can    set    the
-        PCRE_NO_UTF8_CHECK option when calling pcre_exec(). You might  want  to
+        PCRE_NO_UTF8_CHECK  option  when calling pcre_exec(). You might want to
-        do  this  for the second and subsequent calls to pcre_exec() if you are
+        do this for the second and subsequent calls to pcre_exec() if  you  are
-        making repeated calls to find all  the  matches  in  a  single  subject
+        making  repeated  calls  to  find  all  the matches in a single subject
-        string.  However,  you  should  be  sure  that the value of startoffset
+        string. However, you should be  sure  that  the  value  of  startoffset
-        points to the start of a UTF-8 character.  When  PCRE_NO_UTF8_CHECK  is
+        points  to  the  start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is
-        set,  the  effect of passing an invalid UTF-8 string as a subject, or a
+        set, the effect of passing an invalid UTF-8 string as a subject,  or  a
-        value of startoffset that does not point to the start of a UTF-8  char-
+        value  of startoffset that does not point to the start of a UTF-8 char-
         acter, is undefined. Your program may crash.
           PCRE_PARTIAL
-        This  option  turns  on  the  partial  matching feature. If the subject
+        This option turns on the  partial  matching  feature.  If  the  subject
-        string fails to match the pattern, but at some point during the  match-
+        string  fails to match the pattern, but at some point during the match-
-        ing  process  the  end of the subject was reached (that is, the subject
+        ing process the end of the subject was reached (that  is,  the  subject
-        partially matches the pattern and the failure to  match  occurred  only
+        partially  matches  the  pattern and the failure to match occurred only
-        because  there were not enough subject characters), pcre_exec() returns
+        because there were not enough subject characters), pcre_exec()  returns
-        PCRE_ERROR_PARTIAL instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL  is
+        PCRE_ERROR_PARTIAL  instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is
-        used,  there  are restrictions on what may appear in the pattern. These
+        used, there are restrictions on what may appear in the  pattern.  These
         are discussed in the pcrepartial documentation.
     The string to be matched by pcre_exec()
-        The subject string is passed to pcre_exec() as a pointer in subject,  a
+        The  subject string is passed to pcre_exec() as a pointer in subject, a
-        length  in  length, and a starting byte offset in startoffset. In UTF-8
+        length in length, and a starting byte offset in startoffset.  In  UTF-8
-        mode, the byte offset must point to the start  of  a  UTF-8  character.
+        mode,  the  byte  offset  must point to the start of a UTF-8 character.
-        Unlike  the  pattern string, the subject may contain binary zero bytes.
+        Unlike the pattern string, the subject may contain binary  zero  bytes.
-        When the starting offset is zero, the search for a match starts at  the
+        When  the starting offset is zero, the search for a match starts at the
         beginning of the subject, and this is by far the most common case.
-        A  non-zero  starting offset is useful when searching for another match
+        A non-zero starting offset is useful when searching for  another  match
-        in the same subject by calling pcre_exec() again after a previous  suc-
+        in  the same subject by calling pcre_exec() again after a previous suc-
-        cess.   Setting  startoffset differs from just passing over a shortened
+        cess.  Setting startoffset differs from just passing over  a  shortened
-        string and setting PCRE_NOTBOL in the case of  a  pattern  that  begins
+        string  and  setting  PCRE_NOTBOL  in the case of a pattern that begins
         with any kind of lookbehind. For example, consider the pattern
           \Biss\B
-        which  finds  occurrences  of "iss" in the middle of words. (\B matches
+        which finds occurrences of "iss" in the middle of  words.  (\B  matches
-        only if the current position in the subject is not  a  word  boundary.)
+        only  if  the  current position in the subject is not a word boundary.)
-        When  applied  to the string "Mississipi" the first call to pcre_exec()
+        When applied to the string "Mississipi" the first call  to  pcre_exec()
-        finds the first occurrence. If pcre_exec() is called  again  with  just
+        finds  the  first  occurrence. If pcre_exec() is called again with just
-        the  remainder  of  the  subject,  namely  "issipi", it does not match,
+        the remainder of the subject,  namely  "issipi",  it  does  not  match,
         because \B is always false at the start of the subject, which is deemed
-        to  be  a  word  boundary. However, if pcre_exec() is passed the entire
+        to be a word boundary. However, if pcre_exec()  is  passed  the  entire
         string again, but with startoffset set to 4, it finds the second occur-
-        rence  of "iss" because it is able to look behind the starting point to
+        rence of "iss" because it is able to look behind the starting point  to
         discover that it is preceded by a letter.
-        If a non-zero starting offset is passed when the pattern  is  anchored,
+        If  a  non-zero starting offset is passed when the pattern is anchored,
         one attempt to match at the given offset is made. This can only succeed
-        if the pattern does not require the match to be at  the  start  of  the
+        if  the  pattern  does  not require the match to be at the start of the
         subject.
     How pcre_exec() returns captured substrings
-        In  general, a pattern matches a certain portion of the subject, and in
+        In general, a pattern matches a certain portion of the subject, and  in
-        addition, further substrings from the subject  may  be  picked  out  by
+        addition,  further  substrings  from  the  subject may be picked out by
-        parts  of  the  pattern.  Following the usage in Jeffrey Friedl's book,
+        parts of the pattern. Following the usage  in  Jeffrey  Friedl's  book,
-        this is called "capturing" in what follows, and the  phrase  "capturing
+        this  is  called "capturing" in what follows, and the phrase "capturing
-        subpattern"  is  used for a fragment of a pattern that picks out a sub-
+        subpattern" is used for a fragment of a pattern that picks out  a  sub-
-        string. PCRE supports several other kinds of  parenthesized  subpattern
+        string.  PCRE  supports several other kinds of parenthesized subpattern
         that do not cause substrings to be captured.
-        Captured  substrings are returned to the caller via a vector of integer
+        Captured substrings are returned to the caller via a vector of  integer
-        offsets whose address is passed in ovector. The number of  elements  in
+        offsets  whose  address is passed in ovector. The number of elements in
-        the  vector is passed in ovecsize, which must be a non-negative number.
+        the vector is passed in ovecsize, which must be a non-negative  number.
         Note: this argument is NOT the size of ovector in bytes.
-        The first two-thirds of the vector is used to pass back  captured  sub-
+        The  first  two-thirds of the vector is used to pass back captured sub-
-        strings,  each  substring using a pair of integers. The remaining third
+        strings, each substring using a pair of integers. The  remaining  third
-        of the vector is used as workspace by pcre_exec() while  matching  cap-
+        of  the  vector is used as workspace by pcre_exec() while matching cap-
-        turing  subpatterns, and is not available for passing back information.
+        turing subpatterns, and is not available for passing back  information.
-        The length passed in ovecsize should always be a multiple of three.  If
+        The  length passed in ovecsize should always be a multiple of three. If
         it is not, it is rounded down.
-        When  a  match  is successful, information about captured substrings is
+        When a match is successful, information about  captured  substrings  is
-        returned in pairs of integers, starting at the  beginning  of  ovector,
+        returned  in  pairs  of integers, starting at the beginning of ovector,
-        and  continuing  up  to two-thirds of its length at the most. The first
+        and continuing up to two-thirds of its length at the  most.  The  first
         element of a pair is set to the offset of the first character in a sub-
-        string,  and  the  second  is  set to the offset of the first character
+        string, and the second is set to the  offset  of  the  first  character
-        after the end of a substring. The  first  pair,  ovector[0]  and  ovec-
+        after  the  end  of  a  substring. The first pair, ovector[0] and ovec-
-        tor[1],  identify  the  portion  of  the  subject string matched by the
+        tor[1], identify the portion of  the  subject  string  matched  by  the
-        entire pattern. The next pair is used for the first  capturing  subpat-
+        entire  pattern.  The next pair is used for the first capturing subpat-
         tern, and so on. The value returned by pcre_exec() is one more than the
         highest numbered pair that has been set. For example, if two substrings
-        have  been captured, the returned value is 3. If there are no capturing
+        have been captured, the returned value is 3. If there are no  capturing
-        subpatterns, the return value from a successful match is 1,  indicating
+        subpatterns,  the return value from a successful match is 1, indicating
         that just the first pair of offsets has been set.
         If a capturing subpattern is matched repeatedly, it is the last portion
         of the string that it matched that is returned.
-        If the vector is too small to hold all the captured substring  offsets,
+        If  the vector is too small to hold all the captured substring offsets,
         it is used as far as possible (up to two-thirds of its length), and the
-        function returns a value of zero. In particular, if the substring  off-
+        function  returns a value of zero. In particular, if the substring off-
         sets are not of interest, pcre_exec() may be called with ovector passed
-        as NULL and ovecsize as zero. However, if  the  pattern  contains  back
+        as  NULL  and  ovecsize  as zero. However, if the pattern contains back
-        references  and  the  ovector is not big enough to remember the related
+        references and the ovector is not big enough to  remember  the  related
-        substrings, PCRE has to get additional memory for use during  matching.
+        substrings,  PCRE has to get additional memory for use during matching.
         Thus it is usually advisable to supply an ovector.
-        The  pcre_info()  function  can  be used to find out how many capturing
+        The pcre_info() function can be used to find  out  how  many  capturing
-        subpatterns there are in a compiled  pattern.  The  smallest  size  for
+        subpatterns  there  are  in  a  compiled pattern. The smallest size for
-        ovector  that  will allow for n captured substrings, in addition to the
+        ovector that will allow for n captured substrings, in addition  to  the
         offsets of the substring matched by the whole pattern, is (n+1)*3.
-        It is possible for capturing subpattern number n+1 to match  some  part
+        It  is  possible for capturing subpattern number n+1 to match some part
         of the subject when subpattern n has not been used at all. For example,
-        if the string "abc" is matched  against  the  pattern  (a|(z))(bc)  the
+        if  the  string  "abc"  is  matched against the pattern (a|(z))(bc) the
         return from the function is 4, and subpatterns 1 and 3 are matched, but
-is not. When this happens, both values in  the  offset  pairs  corre-
+ is  not.  When  this happens, both values in the offset pairs corre-
         sponding to unused subpatterns are set to -1.
-        Offset  values  that correspond to unused subpatterns at the end of the
+        Offset values that correspond to unused subpatterns at the end  of  the
-        expression are also set to -1. For example,  if  the  string  "abc"  is
+        expression  are  also  set  to  -1. For example, if the string "abc" is
-        matched  against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not
+        matched against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are  not
-        matched. The return from the function is 2, because  the  highest  used
+        matched.  The  return  from the function is 2, because the highest used
         capturing subpattern number is 1. However, you can refer to the offsets
-        for the second and third capturing subpatterns if  you  wish  (assuming
+        for  the  second  and third capturing subpatterns if you wish (assuming
         the vector is large enough, of course).
-        Some  convenience  functions  are  provided for extracting the captured
+        Some convenience functions are provided  for  extracting  the  captured
         substrings as separate strings. These are described below.
     Error return values from pcre_exec()
-        If pcre_exec() fails, it returns a negative number. The  following  are
+        If  pcre_exec()  fails, it returns a negative number. The following are
         defined in the header file:
           PCRE_ERROR_NOMATCH        (-1)
-Line 2006 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 2035 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_ERROR_NULL           (-2)
-        Either  code  or  subject  was  passed as NULL, or ovector was NULL and
+        Either code or subject was passed as NULL,  or  ovector  was  NULL  and
         ovecsize was not zero.
           PCRE_ERROR_BADOPTION      (-3)
-Line 2015 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 2044 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_ERROR_BADMAGIC       (-4)
-        PCRE stores a 4-byte "magic number" at the start of the compiled  code,
+        PCRE  stores a 4-byte "magic number" at the start of the compiled code,
         to catch the case when it is passed a junk pointer and to detect when a
         pattern that was compiled in an environment of one endianness is run in
-        an  environment  with the other endianness. This is the error that PCRE
+        an environment with the other endianness. This is the error  that  PCRE
         gives when the magic number is not present.
           PCRE_ERROR_UNKNOWN_OPCODE (-5)
         While running the pattern match, an unknown item was encountered in the
-        compiled  pattern.  This  error  could be caused by a bug in PCRE or by
+        compiled pattern. This error could be caused by a bug  in  PCRE  or  by
         overwriting of the compiled pattern.
           PCRE_ERROR_NOMEMORY       (-6)
-        If a pattern contains back references, but the ovector that  is  passed
+        If  a  pattern contains back references, but the ovector that is passed
         to pcre_exec() is not big enough to remember the referenced substrings,
-        PCRE gets a block of memory at the start of matching to  use  for  this
+        PCRE  gets  a  block of memory at the start of matching to use for this
-        purpose.  If the call via pcre_malloc() fails, this error is given. The
+        purpose. If the call via pcre_malloc() fails, this error is given.  The
         memory is automatically freed at the end of matching.
           PCRE_ERROR_NOSUBSTRING    (-7)
-        This error is used by the pcre_copy_substring(),  pcre_get_substring(),
+        This  error is used by the pcre_copy_substring(), pcre_get_substring(),
         and  pcre_get_substring_list()  functions  (see  below).  It  is  never
         returned by pcre_exec().
           PCRE_ERROR_MATCHLIMIT     (-8)
-        The backtracking limit, as specified by  the  match_limit  field  in  a
+        The  backtracking  limit,  as  specified  by the match_limit field in a
-        pcre_extra  structure  (or  defaulted) was reached. See the description
+        pcre_extra structure (or defaulted) was reached.  See  the  description
         above.
           PCRE_ERROR_CALLOUT        (-9)
         This error is never generated by pcre_exec() itself. It is provided for
-        use  by  callout functions that want to yield a distinctive error code.
+        use by callout functions that want to yield a distinctive  error  code.
         See the pcrecallout documentation for details.
           PCRE_ERROR_BADUTF8        (-10)
-        A string that contains an invalid UTF-8 byte sequence was passed  as  a
+        A  string  that contains an invalid UTF-8 byte sequence was passed as a
         subject.
           PCRE_ERROR_BADUTF8_OFFSET (-11)
         The UTF-8 byte sequence that was passed as a subject was valid, but the
-        value of startoffset did not point to the beginning of a UTF-8  charac-
+        value  of startoffset did not point to the beginning of a UTF-8 charac-
         ter.
           PCRE_ERROR_PARTIAL        (-12)
-        The  subject  string did not match, but it did match partially. See the
+        The subject string did not match, but it did match partially.  See  the
         pcrepartial documentation for details of partial matching.
           PCRE_ERROR_BADPARTIAL     (-13)
-        The PCRE_PARTIAL option was used with  a  compiled  pattern  containing
+        The  PCRE_PARTIAL  option  was  used with a compiled pattern containing
-        items  that are not supported for partial matching. See the pcrepartial
+        items that are not supported for partial matching. See the  pcrepartial
         documentation for details of partial matching.
           PCRE_ERROR_INTERNAL       (-14)
-        An unexpected internal error has occurred. This error could  be  caused
+        An  unexpected  internal error has occurred. This error could be caused
         by a bug in PCRE or by overwriting of the compiled pattern.
           PCRE_ERROR_BADCOUNT       (-15)
-        This  error is given if the value of the ovecsize argument is negative.
+        This error is given if the value of the ovecsize argument is  negative.
           PCRE_ERROR_RECURSIONLIMIT (-21)
         The internal recursion limit, as specified by the match_limit_recursion
-        field  in  a  pcre_extra  structure (or defaulted) was reached. See the
+        field in a pcre_extra structure (or defaulted)  was  reached.  See  the
         description above.
           PCRE_ERROR_BADNEWLINE     (-23)
-Line 2110 
 EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
+Line 2139 
 EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
         int pcre_get_substring_list(const char *subject,
              int *ovector, int stringcount, const char ***listptr);
-        Captured substrings can be  accessed  directly  by  using  the  offsets
+        Captured  substrings  can  be  accessed  directly  by using the offsets
-        returned  by  pcre_exec()  in  ovector.  For convenience, the functions
+        returned by pcre_exec() in  ovector.  For  convenience,  the  functions
         pcre_copy_substring(),    pcre_get_substring(),    and    pcre_get_sub-
-        string_list()  are  provided for extracting captured substrings as new,
+        string_list() are provided for extracting captured substrings  as  new,
-        separate, zero-terminated strings. These functions identify  substrings
+        separate,  zero-terminated strings. These functions identify substrings
-        by  number.  The  next section describes functions for extracting named
+        by number. The next section describes functions  for  extracting  named
         substrings.
-        A substring that contains a binary zero is correctly extracted and  has
+        A  substring that contains a binary zero is correctly extracted and has
-        a  further zero added on the end, but the result is not, of course, a C
+        a further zero added on the end, but the result is not, of course, a  C
-        string.  However, you can process such a string  by  referring  to  the
+        string.   However,  you  can  process such a string by referring to the
-        length  that  is  returned  by  pcre_copy_substring() and pcre_get_sub-
+        length that is  returned  by  pcre_copy_substring()  and  pcre_get_sub-
         string().  Unfortunately, the interface to pcre_get_substring_list() is
-        not  adequate for handling strings containing binary zeros, because the
+        not adequate for handling strings containing binary zeros, because  the
         end of the final string is not independently indicated.
-        The first three arguments are the same for all  three  of  these  func-
+        The  first  three  arguments  are the same for all three of these func-
-        tions:  subject  is  the subject string that has just been successfully
+        tions: subject is the subject string that has  just  been  successfully
         matched, ovector is a pointer to the vector of integer offsets that was
         passed to pcre_exec(), and stringcount is the number of substrings that
-        were captured by the match, including the substring  that  matched  the
+        were  captured  by  the match, including the substring that matched the
         entire regular expression. This is the value returned by pcre_exec() if
-        it is greater than zero. If pcre_exec() returned zero, indicating  that
+        it  is greater than zero. If pcre_exec() returned zero, indicating that
-        it  ran out of space in ovector, the value passed as stringcount should
+        it ran out of space in ovector, the value passed as stringcount  should
         be the number of elements in the vector divided by three.
-        The functions pcre_copy_substring() and pcre_get_substring() extract  a
+        The  functions pcre_copy_substring() and pcre_get_substring() extract a
-        single  substring,  whose  number  is given as stringnumber. A value of
+        single substring, whose number is given as  stringnumber.  A  value  of
-        zero extracts the substring that matched the  entire  pattern,  whereas
+        zero  extracts  the  substring that matched the entire pattern, whereas
-        higher  values  extract  the  captured  substrings.  For pcre_copy_sub-
+        higher values  extract  the  captured  substrings.  For  pcre_copy_sub-
-        string(), the string is placed in buffer,  whose  length  is  given  by
+        string(),  the  string  is  placed  in buffer, whose length is given by
-        buffersize,  while  for  pcre_get_substring()  a new block of memory is
+        buffersize, while for pcre_get_substring() a new  block  of  memory  is
-        obtained via pcre_malloc, and its address is  returned  via  stringptr.
+        obtained  via  pcre_malloc,  and its address is returned via stringptr.
-        The  yield  of  the function is the length of the string, not including
+        The yield of the function is the length of the  string,  not  including
         the terminating zero, or one of these error codes:
           PCRE_ERROR_NOMEMORY       (-6)
-        The buffer was too small for pcre_copy_substring(), or the  attempt  to
+        The  buffer  was too small for pcre_copy_substring(), or the attempt to
         get memory failed for pcre_get_substring().
           PCRE_ERROR_NOSUBSTRING    (-7)
         There is no substring whose number is stringnumber.
-        The  pcre_get_substring_list()  function  extracts  all  available sub-
+        The pcre_get_substring_list()  function  extracts  all  available  sub-
-        strings and builds a list of pointers to them. All this is  done  in  a
+        strings  and  builds  a list of pointers to them. All this is done in a
         single block of memory that is obtained via pcre_malloc. The address of
-        the memory block is returned via listptr, which is also  the  start  of
+        the  memory  block  is returned via listptr, which is also the start of
-        the  list  of  string pointers. The end of the list is marked by a NULL
+        the list of string pointers. The end of the list is marked  by  a  NULL
-        pointer. The yield of the function is zero if all  went  well,  or  the
+        pointer.  The  yield  of  the function is zero if all went well, or the
         error code
           PCRE_ERROR_NOMEMORY       (-6)
         if the attempt to get the memory block failed.
-        When  any of these functions encounter a substring that is unset, which
+        When any of these functions encounter a substring that is unset,  which
-        can happen when capturing subpattern number n+1 matches  some  part  of
+        can  happen  when  capturing subpattern number n+1 matches some part of
-        the  subject, but subpattern n has not been used at all, they return an
+        the subject, but subpattern n has not been used at all, they return  an
         empty string. This can be distinguished from a genuine zero-length sub-
-        string  by inspecting the appropriate offset in ovector, which is nega-
+        string by inspecting the appropriate offset in ovector, which is  nega-
         tive for unset substrings.
-        The two convenience functions pcre_free_substring() and  pcre_free_sub-
+        The  two convenience functions pcre_free_substring() and pcre_free_sub-
-        string_list()  can  be  used  to free the memory returned by a previous
+        string_list() can be used to free the memory  returned  by  a  previous
         call  of  pcre_get_substring()  or  pcre_get_substring_list(),  respec-
-        tively.  They  do  nothing  more  than  call the function pointed to by
+        tively. They do nothing more than  call  the  function  pointed  to  by
-        pcre_free, which of course could be called directly from a  C  program.
+        pcre_free,  which  of course could be called directly from a C program.
-        However,  PCRE is used in some situations where it is linked via a spe-
+        However, PCRE is used in some situations where it is linked via a  spe-
-        cial  interface  to  another  programming  language  that  cannot   use
+        cial   interface  to  another  programming  language  that  cannot  use
-        pcre_free  directly;  it is for these cases that the functions are pro-
+        pcre_free directly; it is for these cases that the functions  are  pro-
         vided.
-Line 2200 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
+Line 2229 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
              int stringcount, const char *stringname,
              const char **stringptr);
-        To extract a substring by name, you first have to find associated  num-
+        To  extract a substring by name, you first have to find associated num-
         ber.  For example, for this pattern
           (a+)b(?<xxx>\d+)...
-Line 2209 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
+Line 2238 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
         be unique (PCRE_DUPNAMES was not set), you can find the number from the
         name by calling pcre_get_stringnumber(). The first argument is the com-
         piled pattern, and the second is the name. The yield of the function is
-        the  subpattern  number,  or PCRE_ERROR_NOSUBSTRING (-7) if there is no
+        the subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if  there  is  no
         subpattern of that name.
         Given the number, you can extract the substring directly, or use one of
         the functions described in the previous section. For convenience, there
         are also two functions that do the whole job.
-        Most   of   the   arguments    of    pcre_copy_named_substring()    and
+        Most    of    the    arguments   of   pcre_copy_named_substring()   and
-        pcre_get_named_substring()  are  the  same  as  those for the similarly
+        pcre_get_named_substring() are the same  as  those  for  the  similarly
-        named functions that extract by number. As these are described  in  the
+        named  functions  that extract by number. As these are described in the
-        previous  section,  they  are not re-described here. There are just two
+        previous section, they are not re-described here. There  are  just  two
         differences:
-        First, instead of a substring number, a substring name is  given.  Sec-
+        First,  instead  of a substring number, a substring name is given. Sec-
         ond, there is an extra argument, given at the start, which is a pointer
-        to the compiled pattern. This is needed in order to gain access to  the
+        to  the compiled pattern. This is needed in order to gain access to the
         name-to-number translation table.
-        These  functions call pcre_get_stringnumber(), and if it succeeds, they
+        These functions call pcre_get_stringnumber(), and if it succeeds,  they
-        then call pcre_copy_substring() or pcre_get_substring(),  as  appropri-
+        then  call  pcre_copy_substring() or pcre_get_substring(), as appropri-
-        ate.  NOTE:  If PCRE_DUPNAMES is set and there are duplicate names, the
+        ate. NOTE: If PCRE_DUPNAMES is set and there are duplicate  names,  the
         behaviour may not be what you want (see the next section).
-Line 2238 
 DUPLICATE SUBPATTERN NAMES
+Line 2267 
 DUPLICATE SUBPATTERN NAMES
         int pcre_get_stringtable_entries(const pcre *code,
              const char *name, char **first, char **last);
-        When a pattern is compiled with the  PCRE_DUPNAMES  option,  names  for
+        When  a  pattern  is  compiled with the PCRE_DUPNAMES option, names for
-        subpatterns  are  not  required  to  be unique. Normally, patterns with
+        subpatterns are not required to  be  unique.  Normally,  patterns  with
-        duplicate names are such that in any one match, only one of  the  named
+        duplicate  names  are such that in any one match, only one of the named
-        subpatterns  participates. An example is shown in the pcrepattern docu-
+        subpatterns participates. An example is shown in the pcrepattern  docu-
         mentation.
-        When   duplicates   are   present,   pcre_copy_named_substring()    and
+        When    duplicates   are   present,   pcre_copy_named_substring()   and
-        pcre_get_named_substring()  return the first substring corresponding to
+        pcre_get_named_substring() return the first substring corresponding  to
-        the given name that is set. If  none  are  set,  PCRE_ERROR_NOSUBSTRING
+        the  given  name  that  is set. If none are set, PCRE_ERROR_NOSUBSTRING
-        (-7)  is  returned;  no  data  is returned. The pcre_get_stringnumber()
+        (-7) is returned; no  data  is  returned.  The  pcre_get_stringnumber()
-        function returns one of the numbers that are associated with the  name,
+        function  returns one of the numbers that are associated with the name,
         but it is not defined which it is.
-        If  you want to get full details of all captured substrings for a given
+        If you want to get full details of all captured substrings for a  given
-        name, you must use  the  pcre_get_stringtable_entries()  function.  The
+        name,  you  must  use  the pcre_get_stringtable_entries() function. The
         first argument is the compiled pattern, and the second is the name. The
-        third and fourth are pointers to variables which  are  updated  by  the
+        third  and  fourth  are  pointers to variables which are updated by the
         function. After it has run, they point to the first and last entries in
-        the name-to-number table  for  the  given  name.  The  function  itself
+        the  name-to-number  table  for  the  given  name.  The function itself
-        returns  the  length  of  each entry, or PCRE_ERROR_NOSUBSTRING (-7) if
+        returns the length of each entry,  or  PCRE_ERROR_NOSUBSTRING  (-7)  if
-        there are none. The format of the table is described above in the  sec-
+        there  are none. The format of the table is described above in the sec-
-        tion  entitled  Information  about  a  pattern.  Given all the relevant
+        tion entitled Information about a  pattern.   Given  all  the  relevant
-        entries for the name, you can extract each of their numbers, and  hence
+        entries  for the name, you can extract each of their numbers, and hence
         the captured data, if any.
  FINDING ALL POSSIBLE MATCHES
-        The  traditional  matching  function  uses a similar algorithm to Perl,
+        The traditional matching function uses a  similar  algorithm  to  Perl,
         which stops when it finds the first match, starting at a given point in
-        the  subject.  If you want to find all possible matches, or the longest
+        the subject. If you want to find all possible matches, or  the  longest
-        possible match, consider using the alternative matching  function  (see
+        possible  match,  consider using the alternative matching function (see
-        below)  instead.  If you cannot use the alternative function, but still
+        below) instead. If you cannot use the alternative function,  but  still
-        need to find all possible matches, you can kludge it up by  making  use
+        need  to  find all possible matches, you can kludge it up by making use
         of the callout facility, which is described in the pcrecallout documen-
         tation.
         What you have to do is to insert a callout right at the end of the pat-
-        tern.   When your callout function is called, extract and save the cur-
+        tern.  When your callout function is called, extract and save the  cur-
-        rent matched substring. Then return  1,  which  forces  pcre_exec()  to
+        rent  matched  substring.  Then  return  1, which forces pcre_exec() to
-        backtrack  and  try other alternatives. Ultimately, when it runs out of
+        backtrack and try other alternatives. Ultimately, when it runs  out  of
         matches, pcre_exec() will yield PCRE_ERROR_NOMATCH.
-Line 2289 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2318 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
              int options, int *ovector, int ovecsize,
              int *workspace, int wscount);
-        The function pcre_dfa_exec()  is  called  to  match  a  subject  string
+        The  function  pcre_dfa_exec()  is  called  to  match  a subject string
-        against  a  compiled pattern, using a matching algorithm that scans the
+        against a compiled pattern, using a matching algorithm that  scans  the
-        subject string just once, and does not backtrack.  This  has  different
+        subject  string  just  once, and does not backtrack. This has different
-        characteristics  to  the  normal  algorithm, and is not compatible with
+        characteristics to the normal algorithm, and  is  not  compatible  with
-        Perl. Some of the features of PCRE patterns are not  supported.  Never-
+        Perl.  Some  of the features of PCRE patterns are not supported. Never-
-        theless,  there are times when this kind of matching can be useful. For
+        theless, there are times when this kind of matching can be useful.  For
         a discussion of the two matching algorithms, see the pcrematching docu-
         mentation.
-        The  arguments  for  the  pcre_dfa_exec()  function are the same as for
+        The arguments for the pcre_dfa_exec() function  are  the  same  as  for
         pcre_exec(), plus two extras. The ovector argument is used in a differ-
-        ent  way,  and  this is described below. The other common arguments are
+        ent way, and this is described below. The other  common  arguments  are
-        used in the same way as for pcre_exec(), so their  description  is  not
+        used  in  the  same way as for pcre_exec(), so their description is not
         repeated here.
-        The  two  additional  arguments provide workspace for the function. The
+        The two additional arguments provide workspace for  the  function.  The
-        workspace vector should contain at least 20 elements. It  is  used  for
+        workspace  vector  should  contain at least 20 elements. It is used for
         keeping  track  of  multiple  paths  through  the  pattern  tree.  More
-        workspace will be needed for patterns and subjects where  there  are  a
+        workspace  will  be  needed for patterns and subjects where there are a
         lot of potential matches.
         Here is an example of a simple call to pcre_dfa_exec():
-Line 2329 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2358 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
     Option bits for pcre_dfa_exec()
-        The  unused  bits  of  the options argument for pcre_dfa_exec() must be
+        The unused bits of the options argument  for  pcre_dfa_exec()  must  be
-        zero. The only bits  that  may  be  set  are  PCRE_ANCHORED,  PCRE_NEW-
+        zero.  The  only  bits  that  may  be  set are PCRE_ANCHORED, PCRE_NEW-
-        LINE_xxx,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK,
+        LINE_xxx, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,  PCRE_NO_UTF8_CHECK,
         PCRE_PARTIAL, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last
         three of these are the same as for pcre_exec(), so their description is
         not repeated here.
           PCRE_PARTIAL
-        This has the same general effect as it does for  pcre_exec(),  but  the
+        This  has  the  same general effect as it does for pcre_exec(), but the
-        details   are   slightly   different.  When  PCRE_PARTIAL  is  set  for
+        details  are  slightly  different.  When  PCRE_PARTIAL   is   set   for
-        pcre_dfa_exec(), the return code PCRE_ERROR_NOMATCH is  converted  into
+        pcre_dfa_exec(),  the  return code PCRE_ERROR_NOMATCH is converted into
-        PCRE_ERROR_PARTIAL  if  the  end  of the subject is reached, there have
+        PCRE_ERROR_PARTIAL if the end of the subject  is  reached,  there  have
         been no complete matches, but there is still at least one matching pos-
-        sibility.  The portion of the string that provided the partial match is
+        sibility. The portion of the string that provided the partial match  is
         set as the first matching string.
           PCRE_DFA_SHORTEST
-        Setting the PCRE_DFA_SHORTEST option causes the matching  algorithm  to
+        Setting  the  PCRE_DFA_SHORTEST option causes the matching algorithm to
         stop as soon as it has found one match. Because of the way the alterna-
-        tive algorithm works, this is necessarily the shortest  possible  match
+        tive  algorithm  works, this is necessarily the shortest possible match
         at the first possible matching point in the subject string.
           PCRE_DFA_RESTART
-        When  pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option, and
+        When pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option,  and
-        returns a partial match, it is possible to call it  again,  with  addi-
+        returns  a  partial  match, it is possible to call it again, with addi-
-        tional  subject  characters,  and have it continue with the same match.
+        tional subject characters, and have it continue with  the  same  match.
-        The PCRE_DFA_RESTART option requests this action; when it is  set,  the
+        The  PCRE_DFA_RESTART  option requests this action; when it is set, the
-        workspace  and wscount options must reference the same vector as before
+        workspace and wscount options must reference the same vector as  before
-        because data about the match so far is left in  them  after  a  partial
+        because  data  about  the  match so far is left in them after a partial
-        match.  There  is  more  discussion of this facility in the pcrepartial
+        match. There is more discussion of this  facility  in  the  pcrepartial
         documentation.
     Successful returns from pcre_dfa_exec()
-        When pcre_dfa_exec() succeeds, it may have matched more than  one  sub-
+        When  pcre_dfa_exec()  succeeds, it may have matched more than one sub-
         string in the subject. Note, however, that all the matches from one run
-        of the function start at the same point in  the  subject.  The  shorter
+        of  the  function  start  at the same point in the subject. The shorter
-        matches  are all initial substrings of the longer matches. For example,
+        matches are all initial substrings of the longer matches. For  example,
         if the pattern
           <.*>
-Line 2384 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2413 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
           <something> <something else>
           <something> <something else> <something further>
-        On success, the yield of the function is a number  greater  than  zero,
+        On  success,  the  yield of the function is a number greater than zero,
-        which  is  the  number of matched substrings. The substrings themselves
+        which is the number of matched substrings.  The  substrings  themselves
-        are returned in ovector. Each string uses two elements;  the  first  is
+        are  returned  in  ovector. Each string uses two elements; the first is
-        the  offset  to  the start, and the second is the offset to the end. In
+        the offset to the start, and the second is the offset to  the  end.  In
-        fact, all the strings have the same start  offset.  (Space  could  have
+        fact,  all  the  strings  have the same start offset. (Space could have
-        been  saved by giving this only once, but it was decided to retain some
+        been saved by giving this only once, but it was decided to retain  some
-        compatibility with the way pcre_exec() returns data,  even  though  the
+        compatibility  with  the  way pcre_exec() returns data, even though the
         meaning of the strings is different.)
         The strings are returned in reverse order of length; that is, the long-
-        est matching string is given first. If there were too many  matches  to
+        est  matching  string is given first. If there were too many matches to
-        fit  into ovector, the yield of the function is zero, and the vector is
+        fit into ovector, the yield of the function is zero, and the vector  is
         filled with the longest matches.
     Error returns from pcre_dfa_exec()
-        The pcre_dfa_exec() function returns a negative number when  it  fails.
+        The  pcre_dfa_exec()  function returns a negative number when it fails.
-        Many  of  the  errors  are  the  same as for pcre_exec(), and these are
+        Many of the errors are the same  as  for  pcre_exec(),  and  these  are
-        described above.  There are in addition the following errors  that  are
+        described  above.   There are in addition the following errors that are
         specific to pcre_dfa_exec():
           PCRE_ERROR_DFA_UITEM      (-16)
-        This  return is given if pcre_dfa_exec() encounters an item in the pat-
+        This return is given if pcre_dfa_exec() encounters an item in the  pat-
-        tern that it does not support, for instance, the use of \C  or  a  back
+        tern  that  it  does not support, for instance, the use of \C or a back
         reference.
           PCRE_ERROR_DFA_UCOND      (-17)
-        This  return  is  given  if pcre_dfa_exec() encounters a condition item
+        This return is given if pcre_dfa_exec()  encounters  a  condition  item
-        that uses a back reference for the condition, or a test  for  recursion
+        that  uses  a back reference for the condition, or a test for recursion
         in a specific group. These are not supported.
           PCRE_ERROR_DFA_UMLIMIT    (-18)
-        This  return  is given if pcre_dfa_exec() is called with an extra block
+        This return is given if pcre_dfa_exec() is called with an  extra  block
         that contains a setting of the match_limit field. This is not supported
         (it is meaningless).
           PCRE_ERROR_DFA_WSSIZE     (-19)
-        This  return  is  given  if  pcre_dfa_exec()  runs  out of space in the
+        This return is given if  pcre_dfa_exec()  runs  out  of  space  in  the
         workspace vector.
           PCRE_ERROR_DFA_RECURSE    (-20)
-        When a recursive subpattern is processed, the matching  function  calls
+        When  a  recursive subpattern is processed, the matching function calls
-        itself  recursively,  using  private vectors for ovector and workspace.
+        itself recursively, using private vectors for  ovector  and  workspace.
-        This error is given if the output vector  is  not  large  enough.  This
+        This  error  is  given  if  the output vector is not large enough. This
         should be extremely rare, as a vector of size 1000 is used.
  SEE ALSO
-        pcrebuild(3),  pcrecallout(3), pcrecpp(3)(3), pcrematching(3), pcrepar-
+        pcrebuild(3), pcrecallout(3), pcrecpp(3)(3), pcrematching(3),  pcrepar-
-        tial(3), pcreposix(3), pcreprecompile(3), pcresample(3),  pcrestack(3).
+        tial(3),  pcreposix(3), pcreprecompile(3), pcresample(3), pcrestack(3).
  AUTHOR
-Line 2451 
 AUTHOR
+Line 2480 
 AUTHOR
  REVISION
-        Last updated: 09 August 2007
+        Last updated: 21 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2797 
 PCRE REGULAR EXPRESSION DETAILS
+Line 2826 
 PCRE REGULAR EXPRESSION DETAILS
         discussed in the pcrematching page.
+ NEWLINE CONVENTIONS
+        PCRE  supports five different conventions for indicating line breaks in
+        strings: a single CR (carriage return) character, a  single  LF  (line-
+        feed) character, the two-character sequence CRLF, any of the three pre-
+        ceding, or any Unicode newline sequence. The pcreapi page  has  further
+        discussion  about newlines, and shows how to set the newline convention
+        in the options arguments for the compiling and matching functions.
+        It is also possible to specify a newline convention by starting a  pat-
+        tern string with one of the following five sequences:
+          (*CR)        carriage return
+          (*LF)        linefeed
+          (*CRLF)      carriage return, followed by linefeed
+          (*ANYCRLF)   any of the three above
+          (*ANY)       all Unicode newline sequences
+        These override the default and the options given to pcre_compile(). For
+        example, on a Unix system where LF is the default newline sequence, the
+        pattern
+          (*CR)a.b
+        changes the convention to CR. That pattern matches "a\nb" because LF is
+        no longer a newline. Note that these special settings,  which  are  not
+        Perl-compatible,  are  recognized  only at the very start of a pattern,
+        and that they must be in upper case.
  CHARACTERS AND METACHARACTERS
-        A  regular  expression  is  a pattern that is matched against a subject
+        A regular expression is a pattern that is  matched  against  a  subject
-        string from left to right. Most characters stand for  themselves  in  a
+        string  from  left  to right. Most characters stand for themselves in a
-        pattern,  and  match  the corresponding characters in the subject. As a
+        pattern, and match the corresponding characters in the  subject.  As  a
         trivial example, the pattern
           The quick brown fox
         matches a portion of a subject string that is identical to itself. When
-        caseless  matching is specified (the PCRE_CASELESS option), letters are
+        caseless matching is specified (the PCRE_CASELESS option), letters  are
-        matched independently of case. In UTF-8 mode, PCRE  always  understands
+        matched  independently  of case. In UTF-8 mode, PCRE always understands
-        the  concept  of case for characters whose values are less than 128, so
+        the concept of case for characters whose values are less than  128,  so
-        caseless matching is always possible. For characters with  higher  val-
+        caseless  matching  is always possible. For characters with higher val-
-        ues,  the concept of case is supported if PCRE is compiled with Unicode
+        ues, the concept of case is supported if PCRE is compiled with  Unicode
-        property support, but not otherwise.   If  you  want  to  use  caseless
+        property  support,  but  not  otherwise.   If  you want to use caseless
-        matching  for  characters  128  and above, you must ensure that PCRE is
+        matching for characters 128 and above, you must  ensure  that  PCRE  is
         compiled with Unicode property support as well as with UTF-8 support.
-        The power of regular expressions comes  from  the  ability  to  include
+        The  power  of  regular  expressions  comes from the ability to include
-        alternatives  and  repetitions in the pattern. These are encoded in the
+        alternatives and repetitions in the pattern. These are encoded  in  the
         pattern by the use of metacharacters, which do not stand for themselves
         but instead are interpreted in some special way.
-        There  are  two different sets of metacharacters: those that are recog-
+        There are two different sets of metacharacters: those that  are  recog-
-        nized anywhere in the pattern except within square brackets, and  those
+        nized  anywhere in the pattern except within square brackets, and those
-        that  are  recognized  within square brackets. Outside square brackets,
+        that are recognized within square brackets.  Outside  square  brackets,
         the metacharacters are as follows:
           \      general escape character with several uses
-Line 2842 
 CHARACTERS AND METACHARACTERS
+Line 2901 
 CHARACTERS AND METACHARACTERS
                  also "possessive quantifier"
           {      start min/max quantifier
-        Part of a pattern that is in square brackets  is  called  a  "character
+        Part  of  a  pattern  that is in square brackets is called a "character
         class". In a character class the only metacharacters are:
           \      general escape character
-Line 2852 
 CHARACTERS AND METACHARACTERS
+Line 2911 
 CHARACTERS AND METACHARACTERS
                    syntax)
           ]      terminates the character class
-        The  following sections describe the use of each of the metacharacters.
+        The following sections describe the use of each of the  metacharacters.
  BACKSLASH
         The backslash character has several uses. Firstly, if it is followed by
-        a  non-alphanumeric  character,  it takes away any special meaning that
+        a non-alphanumeric character, it takes away any  special  meaning  that
-        character may have. This  use  of  backslash  as  an  escape  character
+        character  may  have.  This  use  of  backslash  as an escape character
         applies both inside and outside character classes.
-        For  example,  if  you want to match a * character, you write \* in the
+        For example, if you want to match a * character, you write  \*  in  the
-        pattern.  This escaping action applies whether  or  not  the  following
+        pattern.   This  escaping  action  applies whether or not the following
-        character  would  otherwise be interpreted as a metacharacter, so it is
+        character would otherwise be interpreted as a metacharacter, so  it  is
-        always safe to precede a non-alphanumeric  with  backslash  to  specify
+        always  safe  to  precede  a non-alphanumeric with backslash to specify
-        that  it stands for itself. In particular, if you want to match a back-
+        that it stands for itself. In particular, if you want to match a  back-
         slash, you write \\.
-        If a pattern is compiled with the PCRE_EXTENDED option,  whitespace  in
+        If  a  pattern is compiled with the PCRE_EXTENDED option, whitespace in
-        the  pattern (other than in a character class) and characters between a
+        the pattern (other than in a character class) and characters between  a
         # outside a character class and the next newline are ignored. An escap-
-        ing  backslash  can  be  used to include a whitespace or # character as
+        ing backslash can be used to include a whitespace  or  #  character  as
         part of the pattern.
-        If you want to remove the special meaning from a  sequence  of  charac-
+        If  you  want  to remove the special meaning from a sequence of charac-
-        ters,  you can do so by putting them between \Q and \E. This is differ-
+        ters, you can do so by putting them between \Q and \E. This is  differ-
-        ent from Perl in that $ and  @  are  handled  as  literals  in  \Q...\E
+        ent  from  Perl  in  that  $  and  @ are handled as literals in \Q...\E
-        sequences  in  PCRE, whereas in Perl, $ and @ cause variable interpola-
+        sequences in PCRE, whereas in Perl, $ and @ cause  variable  interpola-
         tion. Note the following examples:
           Pattern            PCRE matches   Perl matches
-Line 2888 
 BACKSLASH
+Line 2947 
 BACKSLASH
           \Qabc\$xyz\E       abc\$xyz       abc\$xyz
           \Qabc\E\$\Qxyz\E   abc$xyz        abc$xyz
-        The \Q...\E sequence is recognized both inside  and  outside  character
+        The  \Q...\E  sequence  is recognized both inside and outside character
         classes.
     Non-printing characters
         A second use of backslash provides a way of encoding non-printing char-
-        acters in patterns in a visible manner. There is no restriction on  the
+        acters  in patterns in a visible manner. There is no restriction on the
-        appearance  of non-printing characters, apart from the binary zero that
+        appearance of non-printing characters, apart from the binary zero  that
-        terminates a pattern, but when a pattern  is  being  prepared  by  text
+        terminates  a  pattern,  but  when  a pattern is being prepared by text
-        editing,  it  is  usually  easier  to  use  one of the following escape
+        editing, it is usually easier  to  use  one  of  the  following  escape
         sequences than the binary character it represents:
           \a        alarm, that is, the BEL character (hex 07)
           \cx       "control-x", where x is any character
           \e        escape (hex 1B)
           \f        formfeed (hex 0C)
-          \n        newline (hex 0A)
+          \n        linefeed (hex 0A)
           \r        carriage return (hex 0D)
           \t        tab (hex 09)
           \ddd      character with octal code ddd, or backreference
           \xhh      character with hex code hh
           \x{hhh..} character with hex code hhh..
-        The precise effect of \cx is as follows: if x is a lower  case  letter,
+        The  precise  effect of \cx is as follows: if x is a lower case letter,
-        it  is converted to upper case. Then bit 6 of the character (hex 40) is
+        it is converted to upper case. Then bit 6 of the character (hex 40)  is
-        inverted.  Thus \cz becomes hex 1A, but \c{ becomes hex 3B,  while  \c;
+        inverted.   Thus  \cz becomes hex 1A, but \c{ becomes hex 3B, while \c;
         becomes hex 7B.
-        After  \x, from zero to two hexadecimal digits are read (letters can be
+        After \x, from zero to two hexadecimal digits are read (letters can  be
-        in upper or lower case). Any number of hexadecimal  digits  may  appear
+        in  upper  or  lower case). Any number of hexadecimal digits may appear
-        between  \x{  and  },  but the value of the character code must be less
+        between \x{ and }, but the value of the character  code  must  be  less
         than 256 in non-UTF-8 mode, and less than 2**31 in UTF-8 mode. That is,
-        the  maximum value in hexadecimal is 7FFFFFFF. Note that this is bigger
+        the maximum value in hexadecimal is 7FFFFFFF. Note that this is  bigger
         than the largest Unicode code point, which is 10FFFF.
-        If characters other than hexadecimal digits appear between \x{  and  },
+        If  characters  other than hexadecimal digits appear between \x{ and },
         or if there is no terminating }, this form of escape is not recognized.
-        Instead, the initial \x will be  interpreted  as  a  basic  hexadecimal
+        Instead,  the  initial  \x  will  be interpreted as a basic hexadecimal
-        escape,  with  no  following  digits, giving a character whose value is
+        escape, with no following digits, giving a  character  whose  value  is
         zero.
         Characters whose value is less than 256 can be defined by either of the
-        two  syntaxes  for  \x. There is no difference in the way they are han-
+        two syntaxes for \x. There is no difference in the way  they  are  han-
         dled. For example, \xdc is exactly the same as \x{dc}.
-        After \0 up to two further octal digits are read. If  there  are  fewer
+        After  \0  up  to two further octal digits are read. If there are fewer
-        than  two  digits,  just  those  that  are  present  are used. Thus the
+        than two digits, just  those  that  are  present  are  used.  Thus  the
         sequence \0\x\07 specifies two binary zeros followed by a BEL character
-        (code  value 7). Make sure you supply two digits after the initial zero
+        (code value 7). Make sure you supply two digits after the initial  zero
         if the pattern character that follows is itself an octal digit.
         The handling of a backslash followed by a digit other than 0 is compli-
         cated.  Outside a character class, PCRE reads it and any following dig-
-        its as a decimal number. If the number is less than  10,  or  if  there
+        its  as  a  decimal  number. If the number is less than 10, or if there
         have been at least that many previous capturing left parentheses in the
-        expression, the entire  sequence  is  taken  as  a  back  reference.  A
+        expression,  the  entire  sequence  is  taken  as  a  back reference. A
-        description  of how this works is given later, following the discussion
+        description of how this works is given later, following the  discussion
         of parenthesized subpatterns.
-        Inside a character class, or if the decimal number is  greater  than  9
+        Inside  a  character  class, or if the decimal number is greater than 9
-        and  there have not been that many capturing subpatterns, PCRE re-reads
+        and there have not been that many capturing subpatterns, PCRE  re-reads
         up to three octal digits following the backslash, and uses them to gen-
-        erate  a data character. Any subsequent digits stand for themselves. In
+        erate a data character. Any subsequent digits stand for themselves.  In
-        non-UTF-8 mode, the value of a character specified  in  octal  must  be
+        non-UTF-8  mode,  the  value  of a character specified in octal must be
-        less  than  \400.  In  UTF-8 mode, values up to \777 are permitted. For
+        less than \400. In UTF-8 mode, values up to  \777  are  permitted.  For
         example:
           \040   is another way of writing a space
-Line 2970 
 BACKSLASH
+Line 3029 
 BACKSLASH
           \81    is either a back reference, or a binary zero
                     followed by the two characters "8" and "1"
-        Note that octal values of 100 or greater must not be  introduced  by  a
+        Note  that  octal  values of 100 or greater must not be introduced by a
         leading zero, because no more than three octal digits are ever read.
         All the sequences that define a single character value can be used both
-        inside and outside character classes. In addition, inside  a  character
+        inside  and  outside character classes. In addition, inside a character
-        class,  the  sequence \b is interpreted as the backspace character (hex
+        class, the sequence \b is interpreted as the backspace  character  (hex
-), and the sequences \R and \X are interpreted as the characters  "R"
+),  and the sequences \R and \X are interpreted as the characters "R"
-        and  "X", respectively. Outside a character class, these sequences have
+        and "X", respectively. Outside a character class, these sequences  have
         different meanings (see below).
     Absolute and relative back references
-        The sequence \g followed by an unsigned or a negative  number,  option-
+        The  sequence  \g followed by an unsigned or a negative number, option-
-        ally  enclosed  in braces, is an absolute or relative back reference. A
+        ally enclosed in braces, is an absolute or relative back  reference.  A
         named back reference can be coded as \g{name}. Back references are dis-
         cussed later, following the discussion of parenthesized subpatterns.
-Line 3004 
 BACKSLASH
+Line 3063 
 BACKSLASH
           \W     any "non-word" character
         Each pair of escape sequences partitions the complete set of characters
-        into  two disjoint sets. Any given character matches one, and only one,
+        into two disjoint sets. Any given character matches one, and only  one,
         of each pair.
         These character type sequences can appear both inside and outside char-
-        acter  classes.  They each match one character of the appropriate type.
+        acter classes. They each match one character of the  appropriate  type.
-        If the current matching point is at the end of the subject string,  all
+        If  the current matching point is at the end of the subject string, all
         of them fail, since there is no character to match.
-        For  compatibility  with Perl, \s does not match the VT character (code
+        For compatibility with Perl, \s does not match the VT  character  (code
-).  This makes it different from the the POSIX "space" class. The  \s
+).   This makes it different from the the POSIX "space" class. The \s
-        characters  are  HT  (9), LF (10), FF (12), CR (13), and space (32). If
+        characters are HT (9), LF (10), FF (12), CR (13), and  space  (32).  If
         "use locale;" is included in a Perl script, \s may match the VT charac-
         ter. In PCRE, it never does.
-        In  UTF-8 mode, characters with values greater than 128 never match \d,
+        In UTF-8 mode, characters with values greater than 128 never match  \d,
         \s, or \w, and always match \D, \S, and \W. This is true even when Uni-
-        code  character  property  support is available. These sequences retain
+        code character property support is available.  These  sequences  retain
         their original meanings from before UTF-8 support was available, mainly
         for efficiency reasons.
         The sequences \h, \H, \v, and \V are Perl 5.10 features. In contrast to
-        the other sequences, these do match certain high-valued  codepoints  in
+        the  other  sequences, these do match certain high-valued codepoints in
         UTF-8 mode.  The horizontal space characters are:
           U+0009     Horizontal tab
-Line 3059 
 BACKSLASH
+Line 3118 
 BACKSLASH
           U+2029     Paragraph separator
         A "word" character is an underscore or any character less than 256 that
-        is a letter or digit. The definition of  letters  and  digits  is  con-
+        is  a  letter  or  digit.  The definition of letters and digits is con-
-        trolled  by PCRE's low-valued character tables, and may vary if locale-
+        trolled by PCRE's low-valued character tables, and may vary if  locale-
-        specific matching is taking place (see "Locale support" in the  pcreapi
+        specific  matching is taking place (see "Locale support" in the pcreapi
-        page).  For  example,  in  a French locale such as "fr_FR" in Unix-like
+        page). For example, in a French locale such  as  "fr_FR"  in  Unix-like
-        systems, or "french" in Windows, some character codes greater than  128
+        systems,  or "french" in Windows, some character codes greater than 128
-        are  used for accented letters, and these are matched by \w. The use of
+        are used for accented letters, and these are matched by \w. The use  of
         locales with Unicode is discouraged.
     Newline sequences
-        Outside a character class, the escape sequence \R matches  any  Unicode
+        Outside  a  character class, the escape sequence \R matches any Unicode
-        newline  sequence. This is a Perl 5.10 feature. In non-UTF-8 mode \R is
+        newline sequence. This is a Perl 5.10 feature. In non-UTF-8 mode \R  is
         equivalent to the following:
           (?>\r\n|\n|\x0b|\f|\r|\x85)
-        This is an example of an "atomic group", details  of  which  are  given
+        This  is  an  example  of an "atomic group", details of which are given
         below.  This particular group matches either the two-character sequence
-        CR followed by LF, or  one  of  the  single  characters  LF  (linefeed,
+        CR  followed  by  LF,  or  one  of  the single characters LF (linefeed,
         U+000A), VT (vertical tab, U+000B), FF (formfeed, U+000C), CR (carriage
         return, U+000D), or NEL (next line, U+0085). The two-character sequence
         is treated as a single unit that cannot be split.
-        In  UTF-8  mode, two additional characters whose codepoints are greater
+        In UTF-8 mode, two additional characters whose codepoints  are  greater
         than 255 are added: LS (line separator, U+2028) and PS (paragraph sepa-
-        rator,  U+2029).   Unicode character property support is not needed for
+        rator, U+2029).  Unicode character property support is not  needed  for
         these characters to be recognized.
         Inside a character class, \R matches the letter "R".
-Line 3092 
 BACKSLASH
+Line 3151 
 BACKSLASH
     Unicode character properties
         When PCRE is built with Unicode character property support, three addi-
-        tional  escape sequences that match characters with specific properties
+        tional escape sequences that match characters with specific  properties
-        are available.  When not in UTF-8 mode, these sequences are  of  course
+        are  available.   When not in UTF-8 mode, these sequences are of course
-        limited  to  testing characters whose codepoints are less than 256, but
+        limited to testing characters whose codepoints are less than  256,  but
         they do work in this mode.  The extra escape sequences are:
           \p{xx}   a character with the xx property
           \P{xx}   a character without the xx property
           \X       an extended Unicode sequence
-        The property names represented by xx above are limited to  the  Unicode
+        The  property  names represented by xx above are limited to the Unicode
         script names, the general category properties, and "Any", which matches
         any character (including newline). Other properties such as "InMusical-
-        Symbols"  are  not  currently supported by PCRE. Note that \P{Any} does
+        Symbols" are not currently supported by PCRE. Note  that  \P{Any}  does
         not match any characters, so always causes a match failure.
         Sets of Unicode characters are defined as belonging to certain scripts.
-        A  character from one of these sets can be matched using a script name.
+        A character from one of these sets can be matched using a script  name.
         For example:
           \p{Greek}
           \P{Han}
-        Those that are not part of an identified script are lumped together  as
+        Those  that are not part of an identified script are lumped together as
         "Common". The current list of scripts is:
         Arabic,  Armenian,  Balinese,  Bengali,  Bopomofo,  Braille,  Buginese,
-        Buhid,  Canadian_Aboriginal,  Cherokee,  Common,   Coptic,   Cuneiform,
+        Buhid,   Canadian_Aboriginal,   Cherokee,  Common,  Coptic,  Cuneiform,
         Cypriot, Cyrillic, Deseret, Devanagari, Ethiopic, Georgian, Glagolitic,
-        Gothic, Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo, Hebrew,  Hira-
+        Gothic,  Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo, Hebrew, Hira-
-        gana,  Inherited,  Kannada,  Katakana,  Kharoshthi,  Khmer, Lao, Latin,
+        gana, Inherited, Kannada,  Katakana,  Kharoshthi,  Khmer,  Lao,  Latin,
         Limbu,  Linear_B,  Malayalam,  Mongolian,  Myanmar,  New_Tai_Lue,  Nko,
-        Ogham,  Old_Italic,  Old_Persian, Oriya, Osmanya, Phags_Pa, Phoenician,
+        Ogham, Old_Italic, Old_Persian, Oriya, Osmanya,  Phags_Pa,  Phoenician,
         Runic,  Shavian,  Sinhala,  Syloti_Nagri,  Syriac,  Tagalog,  Tagbanwa,
         Tai_Le, Tamil, Telugu, Thaana, Thai, Tibetan, Tifinagh, Ugaritic, Yi.
-        Each  character has exactly one general category property, specified by
+        Each character has exactly one general category property, specified  by
         a two-letter abbreviation. For compatibility with Perl, negation can be
-        specified  by  including a circumflex between the opening brace and the
+        specified by including a circumflex between the opening brace  and  the
         property name. For example, \p{^Lu} is the same as \P{Lu}.
         If only one letter is specified with \p or \P, it includes all the gen-
-        eral  category properties that start with that letter. In this case, in
+        eral category properties that start with that letter. In this case,  in
-        the absence of negation, the curly brackets in the escape sequence  are
+        the  absence of negation, the curly brackets in the escape sequence are
         optional; these two examples have the same effect:
           \p{L}
-Line 3186 
 BACKSLASH
+Line 3245 
 BACKSLASH
           Zp    Paragraph separator
           Zs    Space separator
-        The  special property L& is also supported: it matches a character that
+        The special property L& is also supported: it matches a character  that
-        has the Lu, Ll, or Lt property, in other words, a letter  that  is  not
+        has  the  Lu,  Ll, or Lt property, in other words, a letter that is not
         classified as a modifier or "other".
-        The  Cs  (Surrogate)  property  applies only to characters in the range
+        The Cs (Surrogate) property applies only to  characters  in  the  range
-        U+D800 to U+DFFF. Such characters are not valid in UTF-8  strings  (see
+        U+D800  to  U+DFFF. Such characters are not valid in UTF-8 strings (see
         RFC 3629) and so cannot be tested by PCRE, unless UTF-8 validity check-
-        ing has been turned off (see the discussion  of  PCRE_NO_UTF8_CHECK  in
+        ing  has  been  turned off (see the discussion of PCRE_NO_UTF8_CHECK in
         the pcreapi page).
-        The  long  synonyms  for  these  properties that Perl supports (such as
+        The long synonyms for these properties  that  Perl  supports  (such  as
-        \p{Letter}) are not supported by PCRE, nor is it  permitted  to  prefix
+        \p{Letter})  are  not  supported by PCRE, nor is it permitted to prefix
         any of these properties with "Is".
         No character that is in the Unicode table has the Cn (unassigned) prop-
         erty.  Instead, this property is assumed for any code point that is not
         in the Unicode table.
-        Specifying  caseless  matching  does not affect these escape sequences.
+        Specifying caseless matching does not affect  these  escape  sequences.
         For example, \p{Lu} always matches only upper case letters.
-        The \X escape matches any number of Unicode  characters  that  form  an
+        The  \X  escape  matches  any number of Unicode characters that form an
         extended Unicode sequence. \X is equivalent to
           (?>\PM\pM*)
-        That  is,  it matches a character without the "mark" property, followed
+        That is, it matches a character without the "mark"  property,  followed
-        by zero or more characters with the "mark"  property,  and  treats  the
+        by  zero  or  more  characters with the "mark" property, and treats the
-        sequence  as  an  atomic group (see below).  Characters with the "mark"
+        sequence as an atomic group (see below).  Characters  with  the  "mark"
-        property are typically accents that  affect  the  preceding  character.
+        property  are  typically  accents  that affect the preceding character.
-        None  of  them  have  codepoints less than 256, so in non-UTF-8 mode \X
+        None of them have codepoints less than 256, so  in  non-UTF-8  mode  \X
         matches any one character.
-        Matching characters by Unicode property is not fast, because  PCRE  has
+        Matching  characters  by Unicode property is not fast, because PCRE has
-        to  search  a  structure  that  contains data for over fifteen thousand
+        to search a structure that contains  data  for  over  fifteen  thousand
         characters. That is why the traditional escape sequences such as \d and
         \w do not use Unicode properties in PCRE.
     Resetting the match start
         The escape sequence \K, which is a Perl 5.10 feature, causes any previ-
-        ously matched characters not  to  be  included  in  the  final  matched
+        ously  matched  characters  not  to  be  included  in the final matched
         sequence. For example, the pattern:
           foo\Kbar
-        matches  "foobar",  but reports that it has matched "bar". This feature
+        matches "foobar", but reports that it has matched "bar".  This  feature
-        is similar to a lookbehind assertion (described  below).   However,  in
+        is  similar  to  a lookbehind assertion (described below).  However, in
-        this  case, the part of the subject before the real match does not have
+        this case, the part of the subject before the real match does not  have
-        to be of fixed length, as lookbehind assertions do. The use of \K  does
+        to  be of fixed length, as lookbehind assertions do. The use of \K does
-        not  interfere  with  the setting of captured substrings.  For example,
+        not interfere with the setting of captured  substrings.   For  example,
         when the pattern
           (foo)\Kbar
-Line 3245 
 BACKSLASH
+Line 3304 
 BACKSLASH
     Simple assertions
-        The final use of backslash is for certain simple assertions. An  asser-
+        The  final use of backslash is for certain simple assertions. An asser-
-        tion  specifies a condition that has to be met at a particular point in
+        tion specifies a condition that has to be met at a particular point  in
-        a match, without consuming any characters from the subject string.  The
+        a  match, without consuming any characters from the subject string. The
-        use  of subpatterns for more complicated assertions is described below.
+        use of subpatterns for more complicated assertions is described  below.
         The backslashed assertions are:
           \b     matches at a word boundary
-Line 3259 
 BACKSLASH
+Line 3318 
 BACKSLASH
           \z     matches only at the end of the subject
           \G     matches at the first matching position in the subject
-        These assertions may not appear in character classes (but note that  \b
+        These  assertions may not appear in character classes (but note that \b
         has a different meaning, namely the backspace character, inside a char-
         acter class).
-        A word boundary is a position in the subject string where  the  current
+        A  word  boundary is a position in the subject string where the current
-        character  and  the previous character do not both match \w or \W (i.e.
+        character and the previous character do not both match \w or  \W  (i.e.
-        one matches \w and the other matches \W), or the start or  end  of  the
+        one  matches  \w  and the other matches \W), or the start or end of the
         string if the first or last character matches \w, respectively.
-        The  \A,  \Z,  and \z assertions differ from the traditional circumflex
+        The \A, \Z, and \z assertions differ from  the  traditional  circumflex
         and dollar (described in the next section) in that they only ever match
-        at  the  very start and end of the subject string, whatever options are
+        at the very start and end of the subject string, whatever  options  are
-        set. Thus, they are independent of multiline mode. These  three  asser-
+        set.  Thus,  they are independent of multiline mode. These three asser-
         tions are not affected by the PCRE_NOTBOL or PCRE_NOTEOL options, which
-        affect only the behaviour of the circumflex and dollar  metacharacters.
+        affect  only the behaviour of the circumflex and dollar metacharacters.
-        However,  if the startoffset argument of pcre_exec() is non-zero, indi-
+        However, if the startoffset argument of pcre_exec() is non-zero,  indi-
         cating that matching is to start at a point other than the beginning of
-        the  subject,  \A  can never match. The difference between \Z and \z is
+        the subject, \A can never match. The difference between \Z  and  \z  is
         that \Z matches before a newline at the end of the string as well as at
         the very end, whereas \z matches only at the end.
-        The  \G assertion is true only when the current matching position is at
+        The \G assertion is true only when the current matching position is  at
-        the start point of the match, as specified by the startoffset  argument
+        the  start point of the match, as specified by the startoffset argument
-        of  pcre_exec().  It  differs  from \A when the value of startoffset is
+        of pcre_exec(). It differs from \A when the  value  of  startoffset  is
-        non-zero. By calling pcre_exec() multiple times with appropriate  argu-
+        non-zero.  By calling pcre_exec() multiple times with appropriate argu-
         ments, you can mimic Perl's /g option, and it is in this kind of imple-
         mentation where \G can be useful.
-        Note, however, that PCRE's interpretation of \G, as the  start  of  the
+        Note,  however,  that  PCRE's interpretation of \G, as the start of the
         current match, is subtly different from Perl's, which defines it as the
-        end of the previous match. In Perl, these can  be  different  when  the
+        end  of  the  previous  match. In Perl, these can be different when the
-        previously  matched  string was empty. Because PCRE does just one match
+        previously matched string was empty. Because PCRE does just  one  match
         at a time, it cannot reproduce this behaviour.
-        If all the alternatives of a pattern begin with \G, the  expression  is
+        If  all  the alternatives of a pattern begin with \G, the expression is
         anchored to the starting match position, and the "anchored" flag is set
         in the compiled regular expression.
-Line 3301 
 BACKSLASH
+Line 3360 
 BACKSLASH
  CIRCUMFLEX AND DOLLAR
         Outside a character class, in the default matching mode, the circumflex
-        character  is  an  assertion  that is true only if the current matching
+        character is an assertion that is true only  if  the  current  matching
-        point is at the start of the subject string. If the  startoffset  argu-
+        point  is  at the start of the subject string. If the startoffset argu-
-        ment  of  pcre_exec()  is  non-zero,  circumflex can never match if the
+        ment of pcre_exec() is non-zero, circumflex  can  never  match  if  the
-        PCRE_MULTILINE option is unset. Inside a  character  class,  circumflex
+        PCRE_MULTILINE  option  is  unset. Inside a character class, circumflex
         has an entirely different meaning (see below).
-        Circumflex  need  not be the first character of the pattern if a number
+        Circumflex need not be the first character of the pattern if  a  number
-        of alternatives are involved, but it should be the first thing in  each
+        of  alternatives are involved, but it should be the first thing in each
-        alternative  in  which  it appears if the pattern is ever to match that
+        alternative in which it appears if the pattern is ever  to  match  that
-        branch. If all possible alternatives start with a circumflex, that  is,
+        branch.  If all possible alternatives start with a circumflex, that is,
-        if  the  pattern  is constrained to match only at the start of the sub-
+        if the pattern is constrained to match only at the start  of  the  sub-
-        ject, it is said to be an "anchored" pattern.  (There  are  also  other
+        ject,  it  is  said  to be an "anchored" pattern. (There are also other
         constructs that can cause a pattern to be anchored.)
-        A  dollar  character  is  an assertion that is true only if the current
+        A dollar character is an assertion that is true  only  if  the  current
-        matching point is at the end of  the  subject  string,  or  immediately
+        matching  point  is  at  the  end of the subject string, or immediately
         before a newline at the end of the string (by default). Dollar need not
-        be the last character of the pattern if a number  of  alternatives  are
+        be  the  last  character of the pattern if a number of alternatives are
-        involved,  but  it  should  be  the last item in any branch in which it
+        involved, but it should be the last item in  any  branch  in  which  it
         appears. Dollar has no special meaning in a character class.
-        The meaning of dollar can be changed so that it  matches  only  at  the
+        The  meaning  of  dollar  can be changed so that it matches only at the
-        very  end  of  the string, by setting the PCRE_DOLLAR_ENDONLY option at
+        very end of the string, by setting the  PCRE_DOLLAR_ENDONLY  option  at
         compile time. This does not affect the \Z assertion.
         The meanings of the circumflex and dollar characters are changed if the
-        PCRE_MULTILINE  option  is  set.  When  this  is the case, a circumflex
+        PCRE_MULTILINE option is set. When  this  is  the  case,  a  circumflex
-        matches immediately after internal newlines as well as at the start  of
+        matches  immediately after internal newlines as well as at the start of
-        the  subject  string.  It  does not match after a newline that ends the
+        the subject string. It does not match after a  newline  that  ends  the
-        string. A dollar matches before any newlines in the string, as well  as
+        string.  A dollar matches before any newlines in the string, as well as
-        at  the very end, when PCRE_MULTILINE is set. When newline is specified
+        at the very end, when PCRE_MULTILINE is set. When newline is  specified
-        as the two-character sequence CRLF, isolated CR and  LF  characters  do
+        as  the  two-character  sequence CRLF, isolated CR and LF characters do
         not indicate newlines.
-        For  example, the pattern /^abc$/ matches the subject string "def\nabc"
+        For example, the pattern /^abc$/ matches the subject string  "def\nabc"
-        (where \n represents a newline) in multiline mode, but  not  otherwise.
+        (where  \n  represents a newline) in multiline mode, but not otherwise.
-        Consequently,  patterns  that  are anchored in single line mode because
+        Consequently, patterns that are anchored in single  line  mode  because
-        all branches start with ^ are not anchored in  multiline  mode,  and  a
+        all  branches  start  with  ^ are not anchored in multiline mode, and a
-        match  for  circumflex  is  possible  when  the startoffset argument of
+        match for circumflex is  possible  when  the  startoffset  argument  of
-        pcre_exec() is non-zero. The PCRE_DOLLAR_ENDONLY option is  ignored  if
+        pcre_exec()  is  non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if
         PCRE_MULTILINE is set.
-        Note  that  the sequences \A, \Z, and \z can be used to match the start
+        Note that the sequences \A, \Z, and \z can be used to match  the  start
-        and end of the subject in both modes, and if all branches of a  pattern
+        and  end of the subject in both modes, and if all branches of a pattern
-        start  with  \A it is always anchored, whether or not PCRE_MULTILINE is
+        start with \A it is always anchored, whether or not  PCRE_MULTILINE  is
         set.
  FULL STOP (PERIOD, DOT)
         Outside a character class, a dot in the pattern matches any one charac-
-        ter  in  the subject string except (by default) a character that signi-
+        ter in the subject string except (by default) a character  that  signi-
-        fies the end of a line. In UTF-8 mode, the  matched  character  may  be
+        fies  the  end  of  a line. In UTF-8 mode, the matched character may be
         more than one byte long.
-        When  a line ending is defined as a single character, dot never matches
+        When a line ending is defined as a single character, dot never  matches
-        that character; when the two-character sequence CRLF is used, dot  does
+        that  character; when the two-character sequence CRLF is used, dot does
-        not  match  CR  if  it  is immediately followed by LF, but otherwise it
+        not match CR if it is immediately followed  by  LF,  but  otherwise  it
-        matches all characters (including isolated CRs and LFs). When any  Uni-
+        matches  all characters (including isolated CRs and LFs). When any Uni-
-        code  line endings are being recognized, dot does not match CR or LF or
+        code line endings are being recognized, dot does not match CR or LF  or
         any of the other line ending characters.
-        The behaviour of dot with regard to newlines can  be  changed.  If  the
+        The  behaviour  of  dot  with regard to newlines can be changed. If the
-        PCRE_DOTALL  option  is  set,  a dot matches any one character, without
+        PCRE_DOTALL option is set, a dot matches  any  one  character,  without
         exception. If the two-character sequence CRLF is present in the subject
         string, it takes two dots to match it.
-        The  handling of dot is entirely independent of the handling of circum-
+        The handling of dot is entirely independent of the handling of  circum-
-        flex and dollar, the only relationship being  that  they  both  involve
+        flex  and  dollar,  the  only relationship being that they both involve
         newlines. Dot has no special meaning in a character class.
  MATCHING A SINGLE BYTE
         Outside a character class, the escape sequence \C matches any one byte,
-        both in and out of UTF-8 mode. Unlike a  dot,  it  always  matches  any
+        both  in  and  out  of  UTF-8 mode. Unlike a dot, it always matches any
-        line-ending  characters.  The  feature  is provided in Perl in order to
+        line-ending characters. The feature is provided in  Perl  in  order  to
-        match individual bytes in UTF-8 mode. Because it breaks up UTF-8  char-
+        match  individual bytes in UTF-8 mode. Because it breaks up UTF-8 char-
-        acters  into individual bytes, what remains in the string may be a mal-
+        acters into individual bytes, what remains in the string may be a  mal-
-        formed UTF-8 string. For this reason, the \C escape  sequence  is  best
+        formed  UTF-8  string.  For this reason, the \C escape sequence is best
         avoided.
-        PCRE  does  not  allow \C to appear in lookbehind assertions (described
+        PCRE does not allow \C to appear in  lookbehind  assertions  (described
-        below), because in UTF-8 mode this would make it impossible  to  calcu-
+        below),  because  in UTF-8 mode this would make it impossible to calcu-
         late the length of the lookbehind.
-Line 3393 
 SQUARE BRACKETS AND CHARACTER CLASSES
+Line 3452 
 SQUARE BRACKETS AND CHARACTER CLASSES
         An opening square bracket introduces a character class, terminated by a
         closing square bracket. A closing square bracket on its own is not spe-
         cial. If a closing square bracket is required as a member of the class,
-        it should be the first data character in the class  (after  an  initial
+        it  should  be  the first data character in the class (after an initial
         circumflex, if present) or escaped with a backslash.
-        A  character  class matches a single character in the subject. In UTF-8
+        A character class matches a single character in the subject.  In  UTF-8
-        mode, the character may occupy more than one byte. A matched  character
+        mode,  the character may occupy more than one byte. A matched character
         must be in the set of characters defined by the class, unless the first
-        character in the class definition is a circumflex, in  which  case  the
+        character  in  the  class definition is a circumflex, in which case the
-        subject  character  must  not  be in the set defined by the class. If a
+        subject character must not be in the set defined by  the  class.  If  a
-        circumflex is actually required as a member of the class, ensure it  is
+        circumflex  is actually required as a member of the class, ensure it is
         not the first character, or escape it with a backslash.
-        For  example, the character class [aeiou] matches any lower case vowel,
+        For example, the character class [aeiou] matches any lower case  vowel,
-        while [^aeiou] matches any character that is not a  lower  case  vowel.
+        while  [^aeiou]  matches  any character that is not a lower case vowel.
         Note that a circumflex is just a convenient notation for specifying the
-        characters that are in the class by enumerating those that are  not.  A
+        characters  that  are in the class by enumerating those that are not. A
-        class  that starts with a circumflex is not an assertion: it still con-
+        class that starts with a circumflex is not an assertion: it still  con-
-        sumes a character from the subject string, and therefore  it  fails  if
+        sumes  a  character  from the subject string, and therefore it fails if
         the current pointer is at the end of the string.
-        In  UTF-8 mode, characters with values greater than 255 can be included
+        In UTF-8 mode, characters with values greater than 255 can be  included
-        in a class as a literal string of bytes, or by using the  \x{  escaping
+        in  a  class as a literal string of bytes, or by using the \x{ escaping
         mechanism.
-        When  caseless  matching  is set, any letters in a class represent both
+        When caseless matching is set, any letters in a  class  represent  both
-        their upper case and lower case versions, so for  example,  a  caseless
+        their  upper  case  and lower case versions, so for example, a caseless
-        [aeiou]  matches  "A"  as well as "a", and a caseless [^aeiou] does not
+        [aeiou] matches "A" as well as "a", and a caseless  [^aeiou]  does  not
-        match "A", whereas a caseful version would. In UTF-8 mode, PCRE  always
+        match  "A", whereas a caseful version would. In UTF-8 mode, PCRE always
-        understands  the  concept  of case for characters whose values are less
+        understands the concept of case for characters whose  values  are  less
-        than 128, so caseless matching is always possible. For characters  with
+        than  128, so caseless matching is always possible. For characters with
-        higher  values,  the  concept  of case is supported if PCRE is compiled
+        higher values, the concept of case is supported  if  PCRE  is  compiled
-        with Unicode property support, but not otherwise.  If you want  to  use
+        with  Unicode  property support, but not otherwise.  If you want to use
-        caseless  matching  for  characters 128 and above, you must ensure that
+        caseless matching for characters 128 and above, you  must  ensure  that
-        PCRE is compiled with Unicode property support as well  as  with  UTF-8
+        PCRE  is  compiled  with Unicode property support as well as with UTF-8
         support.
-        Characters  that  might  indicate  line breaks are never treated in any
+        Characters that might indicate line breaks are  never  treated  in  any
-        special way  when  matching  character  classes,  whatever  line-ending
+        special  way  when  matching  character  classes,  whatever line-ending
-        sequence  is  in  use,  and  whatever  setting  of  the PCRE_DOTALL and
+        sequence is in  use,  and  whatever  setting  of  the  PCRE_DOTALL  and
         PCRE_MULTILINE options is used. A class such as [^a] always matches one
         of these characters.
-        The  minus (hyphen) character can be used to specify a range of charac-
+        The minus (hyphen) character can be used to specify a range of  charac-
-        ters in a character  class.  For  example,  [d-m]  matches  any  letter
+        ters  in  a  character  class.  For  example,  [d-m] matches any letter
-        between  d  and  m,  inclusive.  If  a minus character is required in a
+        between d and m, inclusive. If a  minus  character  is  required  in  a
-        class, it must be escaped with a backslash  or  appear  in  a  position
+        class,  it  must  be  escaped  with a backslash or appear in a position
-        where  it cannot be interpreted as indicating a range, typically as the
+        where it cannot be interpreted as indicating a range, typically as  the
         first or last character in the class.
         It is not possible to have the literal character "]" as the end charac-
-        ter  of a range. A pattern such as [W-]46] is interpreted as a class of
+        ter of a range. A pattern such as [W-]46] is interpreted as a class  of
-        two characters ("W" and "-") followed by a literal string "46]", so  it
+        two  characters ("W" and "-") followed by a literal string "46]", so it
-        would  match  "W46]"  or  "-46]". However, if the "]" is escaped with a
+        would match "W46]" or "-46]". However, if the "]"  is  escaped  with  a
-        backslash it is interpreted as the end of range, so [W-\]46] is  inter-
+        backslash  it is interpreted as the end of range, so [W-\]46] is inter-
-        preted  as a class containing a range followed by two other characters.
+        preted as a class containing a range followed by two other  characters.
-        The octal or hexadecimal representation of "]" can also be used to  end
+        The  octal or hexadecimal representation of "]" can also be used to end
         a range.
-        Ranges  operate in the collating sequence of character values. They can
+        Ranges operate in the collating sequence of character values. They  can
-        also  be  used  for  characters  specified  numerically,  for   example
+        also   be  used  for  characters  specified  numerically,  for  example
-        [\000-\037].  In UTF-8 mode, ranges can include characters whose values
+        [\000-\037]. In UTF-8 mode, ranges can include characters whose  values
         are greater than 255, for example [\x{100}-\x{2ff}].
         If a range that includes letters is used when caseless matching is set,
         it matches the letters in either case. For example, [W-c] is equivalent
-        to [][\\^_`wxyzabc], matched caselessly,  and  in  non-UTF-8  mode,  if
+        to  [][\\^_`wxyzabc],  matched  caselessly,  and  in non-UTF-8 mode, if
-        character  tables  for  a French locale are in use, [\xc8-\xcb] matches
+        character tables for a French locale are in  use,  [\xc8-\xcb]  matches
-        accented E characters in both cases. In UTF-8 mode, PCRE  supports  the
+        accented  E  characters in both cases. In UTF-8 mode, PCRE supports the
-        concept  of  case for characters with values greater than 128 only when
+        concept of case for characters with values greater than 128  only  when
         it is compiled with Unicode property support.
-        The character types \d, \D, \p, \P, \s, \S, \w, and \W may also  appear
+        The  character types \d, \D, \p, \P, \s, \S, \w, and \W may also appear
-        in  a  character  class,  and add the characters that they match to the
+        in a character class, and add the characters that  they  match  to  the
         class. For example, [\dABCDEF] matches any hexadecimal digit. A circum-
-        flex  can  conveniently  be used with the upper case character types to
+        flex can conveniently be used with the upper case  character  types  to
-        specify a more restricted set of characters  than  the  matching  lower
+        specify  a  more  restricted  set of characters than the matching lower
-        case  type.  For example, the class [^\W_] matches any letter or digit,
+        case type. For example, the class [^\W_] matches any letter  or  digit,
         but not underscore.
-        The only metacharacters that are recognized in  character  classes  are
+        The  only  metacharacters  that are recognized in character classes are
-        backslash,  hyphen  (only  where  it can be interpreted as specifying a
+        backslash, hyphen (only where it can be  interpreted  as  specifying  a
-        range), circumflex (only at the start), opening  square  bracket  (only
+        range),  circumflex  (only  at the start), opening square bracket (only
-        when  it can be interpreted as introducing a POSIX class name - see the
+        when it can be interpreted as introducing a POSIX class name - see  the
-        next section), and the terminating  closing  square  bracket.  However,
+        next  section),  and  the  terminating closing square bracket. However,
         escaping other non-alphanumeric characters does no harm.
  POSIX CHARACTER CLASSES
         Perl supports the POSIX notation for character classes. This uses names
-        enclosed by [: and :] within the enclosing square brackets.  PCRE  also
+        enclosed  by  [: and :] within the enclosing square brackets. PCRE also
         supports this notation. For example,
           [01[:alpha:]%]
-Line 3505 
 POSIX CHARACTER CLASSES
+Line 3564 
 POSIX CHARACTER CLASSES
           word     "word" characters (same as \w)
           xdigit   hexadecimal digits
-        The "space" characters are HT (9), LF (10), VT (11), FF (12), CR  (13),
+        The  "space" characters are HT (9), LF (10), VT (11), FF (12), CR (13),
-        and  space  (32). Notice that this list includes the VT character (code
+        and space (32). Notice that this list includes the VT  character  (code
 ). This makes "space" different to \s, which does not include VT (for
         Perl compatibility).
-        The  name  "word"  is  a Perl extension, and "blank" is a GNU extension
+        The name "word" is a Perl extension, and "blank"  is  a  GNU  extension
-        from Perl 5.8. Another Perl extension is negation, which  is  indicated
+        from  Perl  5.8. Another Perl extension is negation, which is indicated
         by a ^ character after the colon. For example,
           [12[:^digit:]]
-        matches  "1", "2", or any non-digit. PCRE (and Perl) also recognize the
+        matches "1", "2", or any non-digit. PCRE (and Perl) also recognize  the
         POSIX syntax [.ch.] and [=ch=] where "ch" is a "collating element", but
         these are not supported, and an error is given if they are encountered.
-Line 3526 
 POSIX CHARACTER CLASSES
+Line 3585 
 POSIX CHARACTER CLASSES
  VERTICAL BAR
-        Vertical  bar characters are used to separate alternative patterns. For
+        Vertical bar characters are used to separate alternative patterns.  For
         example, the pattern
           gilbert|sullivan
-        matches either "gilbert" or "sullivan". Any number of alternatives  may
+        matches  either "gilbert" or "sullivan". Any number of alternatives may
-        appear,  and  an  empty  alternative  is  permitted (matching the empty
+        appear, and an empty  alternative  is  permitted  (matching  the  empty
         string). The matching process tries each alternative in turn, from left
-        to  right, and the first one that succeeds is used. If the alternatives
+        to right, and the first one that succeeds is used. If the  alternatives
-        are within a subpattern (defined below), "succeeds" means matching  the
+        are  within a subpattern (defined below), "succeeds" means matching the
-        rest  of the main pattern as well as the alternative in the subpattern.
+        rest of the main pattern as well as the alternative in the  subpattern.
  INTERNAL OPTION SETTING
-        The settings of the  PCRE_CASELESS,  PCRE_MULTILINE,  PCRE_DOTALL,  and
+        The  settings  of  the  PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and
-        PCRE_EXTENDED  options  can  be  changed  from  within the pattern by a
+        PCRE_EXTENDED options can be changed  from  within  the  pattern  by  a
-        sequence of Perl option letters enclosed  between  "(?"  and  ")".  The
+        sequence  of  Perl  option  letters  enclosed between "(?" and ")". The
         option letters are
           i  for PCRE_CASELESS
-Line 3553 
 INTERNAL OPTION SETTING
+Line 3612 
 INTERNAL OPTION SETTING
         For example, (?im) sets caseless, multiline matching. It is also possi-
         ble to unset these options by preceding the letter with a hyphen, and a
-        combined  setting and unsetting such as (?im-sx), which sets PCRE_CASE-
+        combined setting and unsetting such as (?im-sx), which sets  PCRE_CASE-
-        LESS and PCRE_MULTILINE while unsetting PCRE_DOTALL and  PCRE_EXTENDED,
+        LESS  and PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED,
-        is  also  permitted.  If  a  letter  appears  both before and after the
+        is also permitted. If a  letter  appears  both  before  and  after  the
         hyphen, the option is unset.
-        When an option change occurs at top level (that is, not inside  subpat-
+        When  an option change occurs at top level (that is, not inside subpat-
-        tern  parentheses),  the change applies to the remainder of the pattern
+        tern parentheses), the change applies to the remainder of  the  pattern
         that follows.  If the change is placed right at the start of a pattern,
         PCRE extracts it into the global options (and it will therefore show up
         in data extracted by the pcre_fullinfo() function).
-        An option change within a subpattern (see below for  a  description  of
+        An  option  change  within a subpattern (see below for a description of
         subpatterns) affects only that part of the current pattern that follows
         it, so
           (a(?i)b)c
         matches abc and aBc and no other strings (assuming PCRE_CASELESS is not
-        used).   By  this means, options can be made to have different settings
+        used).  By this means, options can be made to have  different  settings
-        in different parts of the pattern. Any changes made in one  alternative
+        in  different parts of the pattern. Any changes made in one alternative
-        do  carry  on  into subsequent branches within the same subpattern. For
+        do carry on into subsequent branches within the  same  subpattern.  For
         example,
           (a(?i)b|c)
-        matches "ab", "aB", "c", and "C", even though  when  matching  "C"  the
+        matches  "ab",  "aB",  "c",  and "C", even though when matching "C" the
-        first  branch  is  abandoned before the option setting. This is because
+        first branch is abandoned before the option setting.  This  is  because
-        the effects of option settings happen at compile time. There  would  be
+        the  effects  of option settings happen at compile time. There would be
         some very weird behaviour otherwise.
-        The  PCRE-specific options PCRE_DUPNAMES, PCRE_UNGREEDY, and PCRE_EXTRA
+        The PCRE-specific options PCRE_DUPNAMES, PCRE_UNGREEDY, and  PCRE_EXTRA
-        can be changed in the same way as the Perl-compatible options by  using
+        can  be changed in the same way as the Perl-compatible options by using
         the characters J, U and X respectively.
-Line 3597 
 SUBPATTERNS
+Line 3656 
 SUBPATTERNS
           cat(aract|erpillar|)
-        matches one of the words "cat", "cataract", or  "caterpillar".  Without
+        matches  one  of the words "cat", "cataract", or "caterpillar". Without
-        the  parentheses,  it  would  match  "cataract", "erpillar" or an empty
+        the parentheses, it would match  "cataract",  "erpillar"  or  an  empty
         string.
-. It sets up the subpattern as  a  capturing  subpattern.  This  means
+.  It  sets  up  the  subpattern as a capturing subpattern. This means
-        that,  when  the  whole  pattern  matches,  that portion of the subject
+        that, when the whole pattern  matches,  that  portion  of  the  subject
         string that matched the subpattern is passed back to the caller via the
-        ovector  argument  of pcre_exec(). Opening parentheses are counted from
+        ovector argument of pcre_exec(). Opening parentheses are  counted  from
-        left to right (starting from 1) to obtain  numbers  for  the  capturing
+        left  to  right  (starting  from 1) to obtain numbers for the capturing
         subpatterns.
-        For  example,  if the string "the red king" is matched against the pat-
+        For example, if the string "the red king" is matched against  the  pat-
         tern
           the ((red|white) (king|queen))
-Line 3616 
 SUBPATTERNS
+Line 3675 
 SUBPATTERNS
         the captured substrings are "red king", "red", and "king", and are num-
         bered 1, 2, and 3, respectively.
-        The  fact  that  plain  parentheses  fulfil two functions is not always
+        The fact that plain parentheses fulfil  two  functions  is  not  always
-        helpful.  There are often times when a grouping subpattern is  required
+        helpful.   There are often times when a grouping subpattern is required
-        without  a capturing requirement. If an opening parenthesis is followed
+        without a capturing requirement. If an opening parenthesis is  followed
-        by a question mark and a colon, the subpattern does not do any  captur-
+        by  a question mark and a colon, the subpattern does not do any captur-
-        ing,  and  is  not  counted when computing the number of any subsequent
+        ing, and is not counted when computing the  number  of  any  subsequent
-        capturing subpatterns. For example, if the string "the white queen"  is
+        capturing  subpatterns. For example, if the string "the white queen" is
         matched against the pattern
           the ((?:red|white) (king|queen))
-Line 3629 
 SUBPATTERNS
+Line 3688 
 SUBPATTERNS
         the captured substrings are "white queen" and "queen", and are numbered
 and 2. The maximum number of capturing subpatterns is 65535.
-        As a convenient shorthand, if any option settings are required  at  the
+        As  a  convenient shorthand, if any option settings are required at the
-        start  of  a  non-capturing  subpattern,  the option letters may appear
+        start of a non-capturing subpattern,  the  option  letters  may  appear
         between the "?" and the ":". Thus the two patterns
           (?i:saturday|sunday)
           (?:(?i)saturday|sunday)
         match exactly the same set of strings. Because alternative branches are
-        tried  from  left  to right, and options are not reset until the end of
+        tried from left to right, and options are not reset until  the  end  of
-        the subpattern is reached, an option setting in one branch does  affect
+        the  subpattern is reached, an option setting in one branch does affect
-        subsequent  branches,  so  the above patterns match "SUNDAY" as well as
+        subsequent branches, so the above patterns match "SUNDAY"  as  well  as
         "Saturday".
  DUPLICATE SUBPATTERN NUMBERS
         Perl 5.10 introduced a feature whereby each alternative in a subpattern
-        uses  the same numbers for its capturing parentheses. Such a subpattern
+        uses the same numbers for its capturing parentheses. Such a  subpattern
-        starts with (?| and is itself a non-capturing subpattern. For  example,
+        starts  with (?| and is itself a non-capturing subpattern. For example,
         consider this pattern:
           (?|(Sat)ur|(Sun))day
-        Because  the two alternatives are inside a (?| group, both sets of cap-
+        Because the two alternatives are inside a (?| group, both sets of  cap-
-        turing parentheses are numbered one. Thus, when  the  pattern  matches,
+        turing  parentheses  are  numbered one. Thus, when the pattern matches,
-        you  can  look  at captured substring number one, whichever alternative
+        you can look at captured substring number  one,  whichever  alternative
-        matched. This construct is useful when you want to  capture  part,  but
+        matched.  This  construct  is useful when you want to capture part, but
         not all, of one of a number of alternatives. Inside a (?| group, paren-
-        theses are numbered as usual, but the number is reset at the  start  of
+        theses  are  numbered as usual, but the number is reset at the start of
-        each  branch. The numbers of any capturing buffers that follow the sub-
+        each branch. The numbers of any capturing buffers that follow the  sub-
-        pattern start after the highest number used in any branch. The  follow-
+        pattern  start after the highest number used in any branch. The follow-
-        ing  example  is taken from the Perl documentation.  The numbers under-
+        ing example is taken from the Perl documentation.  The  numbers  under-
         neath show in which buffer the captured content will be stored.
           # before  ---------------branch-reset----------- after
           / ( a )  (?| x ( y ) z | (p (q) r) | (t) u (v) ) ( z ) /x
           # 1            2         2  3        2     3     4
-        A backreference or a recursive call to  a  numbered  subpattern  always
+        A  backreference  or  a  recursive call to a numbered subpattern always
         refers to the first one in the pattern with the given number.
-        An  alternative approach to using this "branch reset" feature is to use
+        An alternative approach to using this "branch reset" feature is to  use
         duplicate named subpatterns, as described in the next section.
  NAMED SUBPATTERNS
-        Identifying capturing parentheses by number is simple, but  it  can  be
+        Identifying  capturing  parentheses  by number is simple, but it can be
-        very  hard  to keep track of the numbers in complicated regular expres-
+        very hard to keep track of the numbers in complicated  regular  expres-
-        sions. Furthermore, if an  expression  is  modified,  the  numbers  may
+        sions.  Furthermore,  if  an  expression  is  modified, the numbers may
-        change.  To help with this difficulty, PCRE supports the naming of sub-
+        change. To help with this difficulty, PCRE supports the naming of  sub-
         patterns. This feature was not added to Perl until release 5.10. Python
-        had  the  feature earlier, and PCRE introduced it at release 4.0, using
+        had the feature earlier, and PCRE introduced it at release  4.0,  using
-        the Python syntax. PCRE now supports both the Perl and the Python  syn-
+        the  Python syntax. PCRE now supports both the Perl and the Python syn-
         tax.
-        In  PCRE,  a subpattern can be named in one of three ways: (?<name>...)
+        In PCRE, a subpattern can be named in one of three  ways:  (?<name>...)
-        or (?'name'...) as in Perl, or (?P<name>...) as in  Python.  References
+        or  (?'name'...)  as in Perl, or (?P<name>...) as in Python. References
         to capturing parentheses from other parts of the pattern, such as back-
-        references, recursion, and conditions, can be made by name as  well  as
+        references,  recursion,  and conditions, can be made by name as well as
         by number.
-        Names  consist  of  up  to  32 alphanumeric characters and underscores.
+        Names consist of up to  32  alphanumeric  characters  and  underscores.
-        Named capturing parentheses are still  allocated  numbers  as  well  as
+        Named  capturing  parentheses  are  still  allocated numbers as well as
-        names,  exactly as if the names were not present. The PCRE API provides
+        names, exactly as if the names were not present. The PCRE API  provides
         function calls for extracting the name-to-number translation table from
         a compiled pattern. There is also a convenience function for extracting
         a captured substring by name.
-        By default, a name must be unique within a pattern, but it is  possible
+        By  default, a name must be unique within a pattern, but it is possible
         to relax this constraint by setting the PCRE_DUPNAMES option at compile
-        time. This can be useful for patterns where only one  instance  of  the
+        time.  This  can  be useful for patterns where only one instance of the
-        named  parentheses  can  match. Suppose you want to match the name of a
+        named parentheses can match. Suppose you want to match the  name  of  a
-        weekday, either as a 3-letter abbreviation or as the full name, and  in
+        weekday,  either as a 3-letter abbreviation or as the full name, and in
         both cases you want to extract the abbreviation. This pattern (ignoring
         the line breaks) does the job:
-Line 3712 
 NAMED SUBPATTERNS
+Line 3771 
 NAMED SUBPATTERNS
           (?<DN>Thu)(?:rsday)?|
           (?<DN>Sat)(?:urday)?
-        There are five capturing substrings, but only one is ever set  after  a
+        There  are  five capturing substrings, but only one is ever set after a
         match.  (An alternative way of solving this problem is to use a "branch
         reset" subpattern, as described in the previous section.)
-        The convenience function for extracting the data by  name  returns  the
+        The  convenience  function  for extracting the data by name returns the
-        substring  for  the first (and in this example, the only) subpattern of
+        substring for the first (and in this example, the only)  subpattern  of
-        that name that matched. This saves searching  to  find  which  numbered
+        that  name  that  matched.  This saves searching to find which numbered
-        subpattern  it  was. If you make a reference to a non-unique named sub-
+        subpattern it was. If you make a reference to a non-unique  named  sub-
-        pattern from elsewhere in the pattern, the one that corresponds to  the
+        pattern  from elsewhere in the pattern, the one that corresponds to the
-        lowest  number  is used. For further details of the interfaces for han-
+        lowest number is used. For further details of the interfaces  for  han-
         dling named subpatterns, see the pcreapi documentation.
  REPETITION
-        Repetition is specified by quantifiers, which can  follow  any  of  the
+        Repetition  is  specified  by  quantifiers, which can follow any of the
         following items:
           a literal data character
-Line 3740 
 REPETITION
+Line 3799 
 REPETITION
           a back reference (see next section)
           a parenthesized subpattern (unless it is an assertion)
-        The  general repetition quantifier specifies a minimum and maximum num-
+        The general repetition quantifier specifies a minimum and maximum  num-
-        ber of permitted matches, by giving the two numbers in  curly  brackets
+        ber  of  permitted matches, by giving the two numbers in curly brackets
-        (braces),  separated  by  a comma. The numbers must be less than 65536,
+        (braces), separated by a comma. The numbers must be  less  than  65536,
         and the first must be less than or equal to the second. For example:
           z{2,4}
-        matches "zz", "zzz", or "zzzz". A closing brace on its  own  is  not  a
+        matches  "zz",  "zzz",  or  "zzzz". A closing brace on its own is not a
-        special  character.  If  the second number is omitted, but the comma is
+        special character. If the second number is omitted, but  the  comma  is
-        present, there is no upper limit; if the second number  and  the  comma
+        present,  there  is  no upper limit; if the second number and the comma
-        are  both omitted, the quantifier specifies an exact number of required
+        are both omitted, the quantifier specifies an exact number of  required
         matches. Thus
           [aeiou]{3,}
-Line 3759 
 REPETITION
+Line 3818 
 REPETITION
           \d{8}
-        matches exactly 8 digits. An opening curly bracket that  appears  in  a
+        matches  exactly  8  digits. An opening curly bracket that appears in a
-        position  where a quantifier is not allowed, or one that does not match
+        position where a quantifier is not allowed, or one that does not  match
-        the syntax of a quantifier, is taken as a literal character. For  exam-
+        the  syntax of a quantifier, is taken as a literal character. For exam-
         ple, {,6} is not a quantifier, but a literal string of four characters.
-        In UTF-8 mode, quantifiers apply to UTF-8  characters  rather  than  to
+        In  UTF-8  mode,  quantifiers  apply to UTF-8 characters rather than to
         individual bytes. Thus, for example, \x{100}{2} matches two UTF-8 char-
         acters, each of which is represented by a two-byte sequence. Similarly,
         when Unicode property support is available, \X{3} matches three Unicode
-        extended sequences, each of which may be several bytes long  (and  they
+        extended  sequences,  each of which may be several bytes long (and they
         may be of different lengths).
         The quantifier {0} is permitted, causing the expression to behave as if
         the previous item and the quantifier were not present.
-        For convenience, the three most common quantifiers have  single-charac-
+        For  convenience, the three most common quantifiers have single-charac-
         ter abbreviations:
           *    is equivalent to {0,}
           +    is equivalent to {1,}
           ?    is equivalent to {0,1}
-        It  is  possible  to construct infinite loops by following a subpattern
+        It is possible to construct infinite loops by  following  a  subpattern
         that can match no characters with a quantifier that has no upper limit,
         for example:
           (a?)*
         Earlier versions of Perl and PCRE used to give an error at compile time
-        for such patterns. However, because there are cases where this  can  be
+        for  such  patterns. However, because there are cases where this can be
-        useful,  such  patterns  are now accepted, but if any repetition of the
+        useful, such patterns are now accepted, but if any  repetition  of  the
-        subpattern does in fact match no characters, the loop is forcibly  bro-
+        subpattern  does in fact match no characters, the loop is forcibly bro-
         ken.
-        By  default,  the quantifiers are "greedy", that is, they match as much
+        By default, the quantifiers are "greedy", that is, they match  as  much
-        as possible (up to the maximum  number  of  permitted  times),  without
+        as  possible  (up  to  the  maximum number of permitted times), without
-        causing  the  rest of the pattern to fail. The classic example of where
+        causing the rest of the pattern to fail. The classic example  of  where
         this gives problems is in trying to match comments in C programs. These
-        appear  between  /*  and  */ and within the comment, individual * and /
+        appear between /* and */ and within the comment,  individual  *  and  /
-        characters may appear. An attempt to match C comments by  applying  the
+        characters  may  appear. An attempt to match C comments by applying the
         pattern
           /\*.*\*/
-Line 3807 
 REPETITION
+Line 3866 
 REPETITION
           /* first comment */  not comment  /* second comment */
-        fails,  because it matches the entire string owing to the greediness of
+        fails, because it matches the entire string owing to the greediness  of
         the .*  item.
-        However, if a quantifier is followed by a question mark, it  ceases  to
+        However,  if  a quantifier is followed by a question mark, it ceases to
         be greedy, and instead matches the minimum number of times possible, so
         the pattern
           /\*.*?\*/
-        does the right thing with the C comments. The meaning  of  the  various
+        does  the  right  thing with the C comments. The meaning of the various
-        quantifiers  is  not  otherwise  changed,  just the preferred number of
+        quantifiers is not otherwise changed,  just  the  preferred  number  of
-        matches.  Do not confuse this use of question mark with its  use  as  a
+        matches.   Do  not  confuse this use of question mark with its use as a
-        quantifier  in its own right. Because it has two uses, it can sometimes
+        quantifier in its own right. Because it has two uses, it can  sometimes
         appear doubled, as in
           \d??\d
-Line 3827 
 REPETITION
+Line 3886 
 REPETITION
         which matches one digit by preference, but can match two if that is the
         only way the rest of the pattern matches.
-        If  the PCRE_UNGREEDY option is set (an option that is not available in
+        If the PCRE_UNGREEDY option is set (an option that is not available  in
-        Perl), the quantifiers are not greedy by default, but  individual  ones
+        Perl),  the  quantifiers are not greedy by default, but individual ones
-        can  be  made  greedy  by following them with a question mark. In other
+        can be made greedy by following them with a  question  mark.  In  other
         words, it inverts the default behaviour.
-        When a parenthesized subpattern is quantified  with  a  minimum  repeat
+        When  a  parenthesized  subpattern  is quantified with a minimum repeat
-        count  that is greater than 1 or with a limited maximum, more memory is
+        count that is greater than 1 or with a limited maximum, more memory  is
-        required for the compiled pattern, in proportion to  the  size  of  the
+        required  for  the  compiled  pattern, in proportion to the size of the
         minimum or maximum.
         If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equiv-
-        alent to Perl's /s) is set, thus allowing the dot  to  match  newlines,
+        alent  to  Perl's  /s) is set, thus allowing the dot to match newlines,
-        the  pattern  is  implicitly anchored, because whatever follows will be
+        the pattern is implicitly anchored, because whatever  follows  will  be
-        tried against every character position in the subject string, so  there
+        tried  against every character position in the subject string, so there
-        is  no  point  in  retrying the overall match at any position after the
+        is no point in retrying the overall match at  any  position  after  the
-        first. PCRE normally treats such a pattern as though it  were  preceded
+        first.  PCRE  normally treats such a pattern as though it were preceded
         by \A.
-        In  cases  where  it  is known that the subject string contains no new-
+        In cases where it is known that the subject  string  contains  no  new-
-        lines, it is worth setting PCRE_DOTALL in order to  obtain  this  opti-
+        lines,  it  is  worth setting PCRE_DOTALL in order to obtain this opti-
         mization, or alternatively using ^ to indicate anchoring explicitly.
-        However,  there is one situation where the optimization cannot be used.
+        However, there is one situation where the optimization cannot be  used.
-        When .*  is inside capturing parentheses that  are  the  subject  of  a
+        When  .*   is  inside  capturing  parentheses that are the subject of a
-        backreference  elsewhere  in the pattern, a match at the start may fail
+        backreference elsewhere in the pattern, a match at the start  may  fail
         where a later one succeeds. Consider, for example:
           (.*)abc\1
-        If the subject is "xyz123abc123" the match point is the fourth  charac-
+        If  the subject is "xyz123abc123" the match point is the fourth charac-
         ter. For this reason, such a pattern is not implicitly anchored.
         When a capturing subpattern is repeated, the value captured is the sub-
-Line 3865 
 REPETITION
+Line 3924 
 REPETITION
           (tweedle[dume]{3}\s*)+
         has matched "tweedledum tweedledee" the value of the captured substring
-        is  "tweedledee".  However,  if there are nested capturing subpatterns,
+        is "tweedledee". However, if there are  nested  capturing  subpatterns,
-        the corresponding captured values may have been set in previous  itera-
+        the  corresponding captured values may have been set in previous itera-
         tions. For example, after
           /(a|(b))+/
-Line 3876 
 REPETITION
+Line 3935 
 REPETITION
  ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS
-        With  both  maximizing ("greedy") and minimizing ("ungreedy" or "lazy")
+        With both maximizing ("greedy") and minimizing ("ungreedy"  or  "lazy")
-        repetition, failure of what follows normally causes the  repeated  item
+        repetition,  failure  of what follows normally causes the repeated item
-        to  be  re-evaluated to see if a different number of repeats allows the
+        to be re-evaluated to see if a different number of repeats  allows  the
-        rest of the pattern to match. Sometimes it is useful to  prevent  this,
+        rest  of  the pattern to match. Sometimes it is useful to prevent this,
-        either  to  change the nature of the match, or to cause it fail earlier
+        either to change the nature of the match, or to cause it  fail  earlier
-        than it otherwise might, when the author of the pattern knows there  is
+        than  it otherwise might, when the author of the pattern knows there is
         no point in carrying on.
-        Consider,  for  example, the pattern \d+foo when applied to the subject
+        Consider, for example, the pattern \d+foo when applied to  the  subject
         line
 bar
         After matching all 6 digits and then failing to match "foo", the normal
-        action  of  the matcher is to try again with only 5 digits matching the
+        action of the matcher is to try again with only 5 digits  matching  the
-        \d+ item, and then with  4,  and  so  on,  before  ultimately  failing.
+        \d+  item,  and  then  with  4,  and  so on, before ultimately failing.
-        "Atomic  grouping"  (a  term taken from Jeffrey Friedl's book) provides
+        "Atomic grouping" (a term taken from Jeffrey  Friedl's  book)  provides
-        the means for specifying that once a subpattern has matched, it is  not
+        the  means for specifying that once a subpattern has matched, it is not
         to be re-evaluated in this way.
-        If  we  use atomic grouping for the previous example, the matcher gives
+        If we use atomic grouping for the previous example, the  matcher  gives
-        up immediately on failing to match "foo" the first time.  The  notation
+        up  immediately  on failing to match "foo" the first time. The notation
         is a kind of special parenthesis, starting with (?> as in this example:
           (?>\d+)foo
-        This kind of parenthesis "locks up" the  part of the  pattern  it  con-
+        This  kind  of  parenthesis "locks up" the  part of the pattern it con-
-        tains  once  it  has matched, and a failure further into the pattern is
+        tains once it has matched, and a failure further into  the  pattern  is
-        prevented from backtracking into it. Backtracking past it  to  previous
+        prevented  from  backtracking into it. Backtracking past it to previous
         items, however, works as normal.
-        An  alternative  description  is that a subpattern of this type matches
+        An alternative description is that a subpattern of  this  type  matches
-        the string of characters that an  identical  standalone  pattern  would
+        the  string  of  characters  that an identical standalone pattern would
         match, if anchored at the current point in the subject string.
         Atomic grouping subpatterns are not capturing subpatterns. Simple cases
         such as the above example can be thought of as a maximizing repeat that
-        must  swallow  everything  it can. So, while both \d+ and \d+? are pre-
+        must swallow everything it can. So, while both \d+ and  \d+?  are  pre-
-        pared to adjust the number of digits they match in order  to  make  the
+        pared  to  adjust  the number of digits they match in order to make the
         rest of the pattern match, (?>\d+) can only match an entire sequence of
         digits.
-        Atomic groups in general can of course contain arbitrarily  complicated
+        Atomic  groups in general can of course contain arbitrarily complicated
-        subpatterns,  and  can  be  nested. However, when the subpattern for an
+        subpatterns, and can be nested. However, when  the  subpattern  for  an
         atomic group is just a single repeated item, as in the example above, a
-        simpler  notation,  called  a "possessive quantifier" can be used. This
+        simpler notation, called a "possessive quantifier" can  be  used.  This
-        consists of an additional + character  following  a  quantifier.  Using
+        consists  of  an  additional  + character following a quantifier. Using
         this notation, the previous example can be rewritten as
           \d++foo
-Line 3932 
 ATOMIC GROUPING AND POSSESSIVE QUANTIFIE
+Line 3991 
 ATOMIC GROUPING AND POSSESSIVE QUANTIFIE
           (abc|xyz){2,3}+
-        Possessive  quantifiers  are  always  greedy;  the   setting   of   the
+        Possessive   quantifiers   are   always  greedy;  the  setting  of  the
         PCRE_UNGREEDY option is ignored. They are a convenient notation for the
-        simpler forms of atomic group. However, there is no difference  in  the
+        simpler  forms  of atomic group. However, there is no difference in the
-        meaning  of  a  possessive  quantifier and the equivalent atomic group,
+        meaning of a possessive quantifier and  the  equivalent  atomic  group,
-        though there may be a performance  difference;  possessive  quantifiers
+        though  there  may  be a performance difference; possessive quantifiers
         should be slightly faster.
-        The  possessive  quantifier syntax is an extension to the Perl 5.8 syn-
+        The possessive quantifier syntax is an extension to the Perl  5.8  syn-
-        tax.  Jeffrey Friedl originated the idea (and the name)  in  the  first
+        tax.   Jeffrey  Friedl  originated the idea (and the name) in the first
         edition of his book. Mike McCloskey liked it, so implemented it when he
-        built Sun's Java package, and PCRE copied it from there. It  ultimately
+        built  Sun's Java package, and PCRE copied it from there. It ultimately
         found its way into Perl at release 5.10.
         PCRE has an optimization that automatically "possessifies" certain sim-
-        ple pattern constructs. For example, the sequence  A+B  is  treated  as
+        ple  pattern  constructs.  For  example, the sequence A+B is treated as
-        A++B  because  there is no point in backtracking into a sequence of A's
+        A++B because there is no point in backtracking into a sequence  of  A's
         when B must follow.
-        When a pattern contains an unlimited repeat inside  a  subpattern  that
+        When  a  pattern  contains an unlimited repeat inside a subpattern that
-        can  itself  be  repeated  an  unlimited number of times, the use of an
+        can itself be repeated an unlimited number of  times,  the  use  of  an
-        atomic group is the only way to avoid some  failing  matches  taking  a
+        atomic  group  is  the  only way to avoid some failing matches taking a
         very long time indeed. The pattern
           (\D+|<\d+>)*[!?]
-        matches  an  unlimited number of substrings that either consist of non-
+        matches an unlimited number of substrings that either consist  of  non-
-        digits, or digits enclosed in <>, followed by either ! or  ?.  When  it
+        digits,  or  digits  enclosed in <>, followed by either ! or ?. When it
         matches, it runs quickly. However, if it is applied to
           aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
-        it  takes  a  long  time  before reporting failure. This is because the
+        it takes a long time before reporting  failure.  This  is  because  the
-        string can be divided between the internal \D+ repeat and the  external
+        string  can be divided between the internal \D+ repeat and the external
-        *  repeat  in  a  large  number of ways, and all have to be tried. (The
+        * repeat in a large number of ways, and all  have  to  be  tried.  (The
-        example uses [!?] rather than a single character at  the  end,  because
+        example  uses  [!?]  rather than a single character at the end, because
-        both  PCRE  and  Perl have an optimization that allows for fast failure
+        both PCRE and Perl have an optimization that allows  for  fast  failure
-        when a single character is used. They remember the last single  charac-
+        when  a single character is used. They remember the last single charac-
-        ter  that  is required for a match, and fail early if it is not present
+        ter that is required for a match, and fail early if it is  not  present
-        in the string.) If the pattern is changed so that  it  uses  an  atomic
+        in  the  string.)  If  the pattern is changed so that it uses an atomic
         group, like this:
           ((?>\D+)|<\d+>)*[!?]
-        sequences  of non-digits cannot be broken, and failure happens quickly.
+        sequences of non-digits cannot be broken, and failure happens  quickly.
  BACK REFERENCES
         Outside a character class, a backslash followed by a digit greater than
 (and possibly further digits) is a back reference to a capturing sub-
-        pattern earlier (that is, to its left) in the pattern,  provided  there
+        pattern  earlier  (that is, to its left) in the pattern, provided there
         have been that many previous capturing left parentheses.
         However, if the decimal number following the backslash is less than 10,
-        it is always taken as a back reference, and causes  an  error  only  if
+        it  is  always  taken  as a back reference, and causes an error only if
-        there  are  not that many capturing left parentheses in the entire pat-
+        there are not that many capturing left parentheses in the  entire  pat-
-        tern. In other words, the parentheses that are referenced need  not  be
+        tern.  In  other words, the parentheses that are referenced need not be
-        to  the left of the reference for numbers less than 10. A "forward back
+        to the left of the reference for numbers less than 10. A "forward  back
-        reference" of this type can make sense when a  repetition  is  involved
+        reference"  of  this  type can make sense when a repetition is involved
-        and  the  subpattern to the right has participated in an earlier itera-
+        and the subpattern to the right has participated in an  earlier  itera-
         tion.
-        It is not possible to have a numerical "forward back  reference"  to  a
+        It  is  not  possible to have a numerical "forward back reference" to a
-        subpattern  whose  number  is  10  or  more using this syntax because a
+        subpattern whose number is 10 or  more  using  this  syntax  because  a
-        sequence such as \50 is interpreted as a character  defined  in  octal.
+        sequence  such  as  \50 is interpreted as a character defined in octal.
         See the subsection entitled "Non-printing characters" above for further
-        details of the handling of digits following a backslash.  There  is  no
+        details  of  the  handling of digits following a backslash. There is no
-        such  problem  when named parentheses are used. A back reference to any
+        such problem when named parentheses are used. A back reference  to  any
         subpattern is possible using named parentheses (see below).
-        Another way of avoiding the ambiguity inherent in  the  use  of  digits
+        Another  way  of  avoiding  the ambiguity inherent in the use of digits
         following a backslash is to use the \g escape sequence, which is a fea-
-        ture introduced in Perl 5.10.  This  escape  must  be  followed  by  an
+        ture  introduced  in  Perl  5.10.  This  escape  must be followed by an
-        unsigned  number  or  a negative number, optionally enclosed in braces.
+        unsigned number or a negative number, optionally  enclosed  in  braces.
         These examples are all identical:
           (ring), \1
           (ring), \g1
           (ring), \g{1}
-        An unsigned number specifies an absolute reference without the  ambigu-
+        An  unsigned number specifies an absolute reference without the ambigu-
         ity that is present in the older syntax. It is also useful when literal
         digits follow the reference. A negative number is a relative reference.
         Consider this example:
-Line 4020 
 BACK REFERENCES
+Line 4079 
 BACK REFERENCES
           (abc(def)ghi)\g{-1}
         The sequence \g{-1} is a reference to the most recently started captur-
-        ing subpattern before \g, that is, is it equivalent to  \2.  Similarly,
+        ing  subpattern  before \g, that is, is it equivalent to \2. Similarly,
         \g{-2} would be equivalent to \1. The use of relative references can be
-        helpful in long patterns, and also in  patterns  that  are  created  by
+        helpful  in  long  patterns,  and  also in patterns that are created by
         joining together fragments that contain references within themselves.
-        A  back  reference matches whatever actually matched the capturing sub-
+        A back reference matches whatever actually matched the  capturing  sub-
-        pattern in the current subject string, rather  than  anything  matching
+        pattern  in  the  current subject string, rather than anything matching
         the subpattern itself (see "Subpatterns as subroutines" below for a way
         of doing that). So the pattern
           (sens|respons)e and \1ibility
-        matches "sense and sensibility" and "response and responsibility",  but
+        matches  "sense and sensibility" and "response and responsibility", but
-        not  "sense and responsibility". If caseful matching is in force at the
+        not "sense and responsibility". If caseful matching is in force at  the
-        time of the back reference, the case of letters is relevant. For  exam-
+        time  of the back reference, the case of letters is relevant. For exam-
         ple,
           ((?i)rah)\s+\1
-        matches  "rah  rah"  and  "RAH RAH", but not "RAH rah", even though the
+        matches "rah rah" and "RAH RAH", but not "RAH  rah",  even  though  the
         original capturing subpattern is matched caselessly.
-        There are several different ways of writing back  references  to  named
+        There  are  several  different ways of writing back references to named
-        subpatterns.  The  .NET syntax \k{name} and the Perl syntax \k<name> or
+        subpatterns. The .NET syntax \k{name} and the Perl syntax  \k<name>  or
-        \k'name' are supported, as is the Python syntax (?P=name). Perl  5.10's
+        \k'name'  are supported, as is the Python syntax (?P=name). Perl 5.10's
         unified back reference syntax, in which \g can be used for both numeric
-        and named references, is also supported. We  could  rewrite  the  above
+        and  named  references,  is  also supported. We could rewrite the above
         example in any of the following ways:
           (?<p1>(?i)rah)\s+\k<p1>
-Line 4054 
 BACK REFERENCES
+Line 4113 
 BACK REFERENCES
           (?P<p1>(?i)rah)\s+(?P=p1)
           (?<p1>(?i)rah)\s+\g{p1}
-        A  subpattern  that  is  referenced  by  name may appear in the pattern
+        A subpattern that is referenced by  name  may  appear  in  the  pattern
         before or after the reference.
-        There may be more than one back reference to the same subpattern. If  a
+        There  may be more than one back reference to the same subpattern. If a
-        subpattern  has  not actually been used in a particular match, any back
+        subpattern has not actually been used in a particular match,  any  back
         references to it always fail. For example, the pattern
           (a|(bc))\2
-        always fails if it starts to match "a" rather than "bc". Because  there
+        always  fails if it starts to match "a" rather than "bc". Because there
-        may  be  many  capturing parentheses in a pattern, all digits following
+        may be many capturing parentheses in a pattern,  all  digits  following
-        the backslash are taken as part of a potential back  reference  number.
+        the  backslash  are taken as part of a potential back reference number.
         If the pattern continues with a digit character, some delimiter must be
-        used to terminate the back reference. If the  PCRE_EXTENDED  option  is
+        used  to  terminate  the back reference. If the PCRE_EXTENDED option is
-        set,  this  can  be  whitespace.  Otherwise an empty comment (see "Com-
+        set, this can be whitespace.  Otherwise an  empty  comment  (see  "Com-
         ments" below) can be used.
-        A back reference that occurs inside the parentheses to which it  refers
+        A  back reference that occurs inside the parentheses to which it refers
-        fails  when  the subpattern is first used, so, for example, (a\1) never
+        fails when the subpattern is first used, so, for example,  (a\1)  never
-        matches.  However, such references can be useful inside  repeated  sub-
+        matches.   However,  such references can be useful inside repeated sub-
         patterns. For example, the pattern
           (a|b\1)+
         matches any number of "a"s and also "aba", "ababbaa" etc. At each iter-
-        ation of the subpattern,  the  back  reference  matches  the  character
+        ation  of  the  subpattern,  the  back  reference matches the character
-        string  corresponding  to  the previous iteration. In order for this to
+        string corresponding to the previous iteration. In order  for  this  to
-        work, the pattern must be such that the first iteration does  not  need
+        work,  the  pattern must be such that the first iteration does not need
-        to  match the back reference. This can be done using alternation, as in
+        to match the back reference. This can be done using alternation, as  in
         the example above, or by a quantifier with a minimum of zero.
  ASSERTIONS
-        An assertion is a test on the characters  following  or  preceding  the
+        An  assertion  is  a  test on the characters following or preceding the
-        current  matching  point that does not actually consume any characters.
+        current matching point that does not actually consume  any  characters.
-        The simple assertions coded as \b, \B, \A, \G, \Z,  \z,  ^  and  $  are
+        The  simple  assertions  coded  as  \b, \B, \A, \G, \Z, \z, ^ and $ are
         described above.
-        More  complicated  assertions  are  coded as subpatterns. There are two
+        More complicated assertions are coded as  subpatterns.  There  are  two
-        kinds: those that look ahead of the current  position  in  the  subject
+        kinds:  those  that  look  ahead of the current position in the subject
-        string,  and  those  that  look  behind  it. An assertion subpattern is
+        string, and those that look  behind  it.  An  assertion  subpattern  is
-        matched in the normal way, except that it does not  cause  the  current
+        matched  in  the  normal way, except that it does not cause the current
         matching position to be changed.
-        Assertion  subpatterns  are  not  capturing subpatterns, and may not be
+        Assertion subpatterns are not capturing subpatterns,  and  may  not  be
-        repeated, because it makes no sense to assert the  same  thing  several
+        repeated,  because  it  makes no sense to assert the same thing several
-        times.  If  any kind of assertion contains capturing subpatterns within
+        times. If any kind of assertion contains capturing  subpatterns  within
-        it, these are counted for the purposes of numbering the capturing  sub-
+        it,  these are counted for the purposes of numbering the capturing sub-
         patterns in the whole pattern.  However, substring capturing is carried
-        out only for positive assertions, because it does not  make  sense  for
+        out  only  for  positive assertions, because it does not make sense for
         negative assertions.
     Lookahead assertions
-Line 4114 
 ASSERTIONS
+Line 4173 
 ASSERTIONS
           \w+(?=;)
-        matches a word followed by a semicolon, but does not include the  semi-
+        matches  a word followed by a semicolon, but does not include the semi-
         colon in the match, and
           foo(?!bar)
-        matches  any  occurrence  of  "foo" that is not followed by "bar". Note
+        matches any occurrence of "foo" that is not  followed  by  "bar".  Note
         that the apparently similar pattern
           (?!foo)bar
-        does not find an occurrence of "bar"  that  is  preceded  by  something
+        does  not  find  an  occurrence  of "bar" that is preceded by something
-        other  than "foo"; it finds any occurrence of "bar" whatsoever, because
+        other than "foo"; it finds any occurrence of "bar" whatsoever,  because
         the assertion (?!foo) is always true when the next three characters are
         "bar". A lookbehind assertion is needed to achieve the other effect.
         If you want to force a matching failure at some point in a pattern, the
-        most convenient way to do it is  with  (?!)  because  an  empty  string
+        most  convenient  way  to  do  it  is with (?!) because an empty string
-        always  matches, so an assertion that requires there not to be an empty
+        always matches, so an assertion that requires there not to be an  empty
         string must always fail.
     Lookbehind assertions
-        Lookbehind assertions start with (?<= for positive assertions and  (?<!
+        Lookbehind  assertions start with (?<= for positive assertions and (?<!
         for negative assertions. For example,
           (?<!foo)bar
-        does  find  an  occurrence  of "bar" that is not preceded by "foo". The
+        does find an occurrence of "bar" that is not  preceded  by  "foo".  The
-        contents of a lookbehind assertion are restricted  such  that  all  the
+        contents  of  a  lookbehind  assertion are restricted such that all the
         strings it matches must have a fixed length. However, if there are sev-
-        eral top-level alternatives, they do not all  have  to  have  the  same
+        eral  top-level  alternatives,  they  do  not all have to have the same
         fixed length. Thus
           (?<=bullock|donkey)
-Line 4153 
 ASSERTIONS
+Line 4212 
 ASSERTIONS
           (?<!dogs?|cats?)
-        causes  an  error at compile time. Branches that match different length
+        causes an error at compile time. Branches that match  different  length
-        strings are permitted only at the top level of a lookbehind  assertion.
+        strings  are permitted only at the top level of a lookbehind assertion.
-        This  is  an  extension  compared  with  Perl (at least for 5.8), which
+        This is an extension compared with  Perl  (at  least  for  5.8),  which
-        requires all branches to match the same length of string. An  assertion
+        requires  all branches to match the same length of string. An assertion
         such as
           (?<=ab(c|de))
-        is  not  permitted,  because  its single top-level branch can match two
+        is not permitted, because its single top-level  branch  can  match  two
-        different lengths, but it is acceptable if rewritten to  use  two  top-
+        different  lengths,  but  it is acceptable if rewritten to use two top-
         level branches:
           (?<=abc|abde)
         In some cases, the Perl 5.10 escape sequence \K (see above) can be used
-        instead of a lookbehind assertion; this is not restricted to  a  fixed-
+        instead  of  a lookbehind assertion; this is not restricted to a fixed-
         length.
-        The  implementation  of lookbehind assertions is, for each alternative,
+        The implementation of lookbehind assertions is, for  each  alternative,
-        to temporarily move the current position back by the fixed  length  and
+        to  temporarily  move the current position back by the fixed length and
         then try to match. If there are insufficient characters before the cur-
         rent position, the assertion fails.
         PCRE does not allow the \C escape (which matches a single byte in UTF-8
-        mode)  to appear in lookbehind assertions, because it makes it impossi-
+        mode) to appear in lookbehind assertions, because it makes it  impossi-
-        ble to calculate the length of the lookbehind. The \X and  \R  escapes,
+        ble  to  calculate the length of the lookbehind. The \X and \R escapes,
         which can match different numbers of bytes, are also not permitted.
-        Possessive  quantifiers  can  be  used  in  conjunction with lookbehind
+        Possessive quantifiers can  be  used  in  conjunction  with  lookbehind
-        assertions to specify efficient matching at  the  end  of  the  subject
+        assertions  to  specify  efficient  matching  at the end of the subject
         string. Consider a simple pattern such as
           abcd$
-        when  applied  to  a  long string that does not match. Because matching
+        when applied to a long string that does  not  match.  Because  matching
         proceeds from left to right, PCRE will look for each "a" in the subject
-        and  then  see  if what follows matches the rest of the pattern. If the
+        and then see if what follows matches the rest of the  pattern.  If  the
         pattern is specified as
           ^.*abcd$
-        the initial .* matches the entire string at first, but when this  fails
+        the  initial .* matches the entire string at first, but when this fails
         (because there is no following "a"), it backtracks to match all but the
-        last character, then all but the last two characters, and so  on.  Once
+        last  character,  then all but the last two characters, and so on. Once
-        again  the search for "a" covers the entire string, from right to left,
+        again the search for "a" covers the entire string, from right to  left,
         so we are no better off. However, if the pattern is written as
           ^.*+(?<=abcd)
-        there can be no backtracking for the .*+ item; it can  match  only  the
+        there  can  be  no backtracking for the .*+ item; it can match only the
-        entire  string.  The subsequent lookbehind assertion does a single test
+        entire string. The subsequent lookbehind assertion does a  single  test
-        on the last four characters. If it fails, the match fails  immediately.
+        on  the last four characters. If it fails, the match fails immediately.
-        For  long  strings, this approach makes a significant difference to the
+        For long strings, this approach makes a significant difference  to  the
         processing time.
     Using multiple assertions
-Line 4214 
 ASSERTIONS
+Line 4273 
 ASSERTIONS
           (?<=\d{3})(?<!999)foo
-        matches "foo" preceded by three digits that are not "999". Notice  that
+        matches  "foo" preceded by three digits that are not "999". Notice that
-        each  of  the  assertions is applied independently at the same point in
+        each of the assertions is applied independently at the  same  point  in
-        the subject string. First there is a  check  that  the  previous  three
+        the  subject  string.  First  there  is a check that the previous three
-        characters  are  all  digits,  and  then there is a check that the same
+        characters are all digits, and then there is  a  check  that  the  same
         three characters are not "999".  This pattern does not match "foo" pre-
-        ceded  by  six  characters,  the first of which are digits and the last
+        ceded by six characters, the first of which are  digits  and  the  last
-        three of which are not "999". For example, it  doesn't  match  "123abc-
+        three  of  which  are not "999". For example, it doesn't match "123abc-
         foo". A pattern to do that is
           (?<=\d{3}...)(?<!999)foo
-        This  time  the  first assertion looks at the preceding six characters,
+        This time the first assertion looks at the  preceding  six  characters,
         checking that the first three are digits, and then the second assertion
         checks that the preceding three characters are not "999".
-Line 4233 
 ASSERTIONS
+Line 4292 
 ASSERTIONS
           (?<=(?<!foo)bar)baz
-        matches  an occurrence of "baz" that is preceded by "bar" which in turn
+        matches an occurrence of "baz" that is preceded by "bar" which in  turn
         is not preceded by "foo", while
           (?<=\d{3}(?!999)...)foo
-        is another pattern that matches "foo" preceded by three digits and  any
+        is  another pattern that matches "foo" preceded by three digits and any
         three characters that are not "999".
  CONDITIONAL SUBPATTERNS
-        It  is possible to cause the matching process to obey a subpattern con-
+        It is possible to cause the matching process to obey a subpattern  con-
-        ditionally or to choose between two alternative subpatterns,  depending
+        ditionally  or to choose between two alternative subpatterns, depending
-        on  the result of an assertion, or whether a previous capturing subpat-
+        on the result of an assertion, or whether a previous capturing  subpat-
-        tern matched or not. The two possible forms of  conditional  subpattern
+        tern  matched  or not. The two possible forms of conditional subpattern
         are
           (?(condition)yes-pattern)
           (?(condition)yes-pattern|no-pattern)
-        If  the  condition is satisfied, the yes-pattern is used; otherwise the
+        If the condition is satisfied, the yes-pattern is used;  otherwise  the
-        no-pattern (if present) is used. If there are more  than  two  alterna-
+        no-pattern  (if  present)  is used. If there are more than two alterna-
         tives in the subpattern, a compile-time error occurs.
-        There  are  four  kinds of condition: references to subpatterns, refer-
+        There are four kinds of condition: references  to  subpatterns,  refer-
         ences to recursion, a pseudo-condition called DEFINE, and assertions.
     Checking for a used subpattern by number
-        If the text between the parentheses consists of a sequence  of  digits,
+        If  the  text between the parentheses consists of a sequence of digits,
-        the  condition  is  true if the capturing subpattern of that number has
+        the condition is true if the capturing subpattern of  that  number  has
-        previously matched. An alternative notation is to  precede  the  digits
+        previously  matched.  An  alternative notation is to precede the digits
         with a plus or minus sign. In this case, the subpattern number is rela-
         tive rather than absolute.  The most recently opened parentheses can be
-        referenced  by  (?(-1),  the  next most recent by (?(-2), and so on. In
+        referenced by (?(-1), the next most recent by (?(-2),  and  so  on.  In
         looping constructs it can also make sense to refer to subsequent groups
         with constructs such as (?(+2).
-        Consider  the  following  pattern, which contains non-significant white
+        Consider the following pattern, which  contains  non-significant  white
         space to make it more readable (assume the PCRE_EXTENDED option) and to
         divide it into three parts for ease of discussion:
           ( \( )?    [^()]+    (?(1) \) )
-        The  first  part  matches  an optional opening parenthesis, and if that
+        The first part matches an optional opening  parenthesis,  and  if  that
         character is present, sets it as the first captured substring. The sec-
-        ond  part  matches one or more characters that are not parentheses. The
+        ond part matches one or more characters that are not  parentheses.  The
         third part is a conditional subpattern that tests whether the first set
         of parentheses matched or not. If they did, that is, if subject started
         with an opening parenthesis, the condition is true, and so the yes-pat-
-        tern  is  executed  and  a  closing parenthesis is required. Otherwise,
+        tern is executed and a  closing  parenthesis  is  required.  Otherwise,
-        since no-pattern is not present, the  subpattern  matches  nothing.  In
+        since  no-pattern  is  not  present, the subpattern matches nothing. In
-        other  words,  this  pattern  matches  a  sequence  of non-parentheses,
+        other words,  this  pattern  matches  a  sequence  of  non-parentheses,
         optionally enclosed in parentheses.
-        If you were embedding this pattern in a larger one,  you  could  use  a
+        If  you  were  embedding  this pattern in a larger one, you could use a
         relative reference:
           ...other stuff... ( \( )?    [^()]+    (?(-1) \) ) ...
-        This  makes  the  fragment independent of the parentheses in the larger
+        This makes the fragment independent of the parentheses  in  the  larger
         pattern.
     Checking for a used subpattern by name
-        Perl uses the syntax (?(<name>)...) or (?('name')...)  to  test  for  a
+        Perl  uses  the  syntax  (?(<name>)...) or (?('name')...) to test for a
-        used  subpattern  by  name.  For compatibility with earlier versions of
+        used subpattern by name. For compatibility  with  earlier  versions  of
-        PCRE, which had this facility before Perl, the syntax  (?(name)...)  is
+        PCRE,  which  had this facility before Perl, the syntax (?(name)...) is
-        also  recognized. However, there is a possible ambiguity with this syn-
+        also recognized. However, there is a possible ambiguity with this  syn-
-        tax, because subpattern names may  consist  entirely  of  digits.  PCRE
+        tax,  because  subpattern  names  may  consist entirely of digits. PCRE
-        looks  first for a named subpattern; if it cannot find one and the name
+        looks first for a named subpattern; if it cannot find one and the  name
-        consists entirely of digits, PCRE looks for a subpattern of  that  num-
+        consists  entirely  of digits, PCRE looks for a subpattern of that num-
-        ber,  which must be greater than zero. Using subpattern names that con-
+        ber, which must be greater than zero. Using subpattern names that  con-
         sist entirely of digits is not recommended.
         Rewriting the above example to use a named subpattern gives this:
-Line 4316 
 CONDITIONAL SUBPATTERNS
+Line 4375 
 CONDITIONAL SUBPATTERNS
     Checking for pattern recursion
         If the condition is the string (R), and there is no subpattern with the
-        name  R, the condition is true if a recursive call to the whole pattern
+        name R, the condition is true if a recursive call to the whole  pattern
         or any subpattern has been made. If digits or a name preceded by amper-
         sand follow the letter R, for example:
           (?(R3)...) or (?(R&name)...)
-        the  condition is true if the most recent recursion is into the subpat-
+        the condition is true if the most recent recursion is into the  subpat-
-        tern whose number or name is given. This condition does not  check  the
+        tern  whose  number or name is given. This condition does not check the
         entire recursion stack.
-        At  "top  level", all these recursion test conditions are false. Recur-
+        At "top level", all these recursion test conditions are  false.  Recur-
         sive patterns are described below.
     Defining subpatterns for use by reference only
-        If the condition is the string (DEFINE), and  there  is  no  subpattern
+        If  the  condition  is  the string (DEFINE), and there is no subpattern
-        with  the  name  DEFINE,  the  condition is always false. In this case,
+        with the name DEFINE, the condition is  always  false.  In  this  case,
-        there may be only one alternative  in  the  subpattern.  It  is  always
+        there  may  be  only  one  alternative  in the subpattern. It is always
-        skipped  if  control  reaches  this  point  in the pattern; the idea of
+        skipped if control reaches this point  in  the  pattern;  the  idea  of
-        DEFINE is that it can be used to define "subroutines" that can be  ref-
+        DEFINE  is that it can be used to define "subroutines" that can be ref-
-        erenced  from elsewhere. (The use of "subroutines" is described below.)
+        erenced from elsewhere. (The use of "subroutines" is described  below.)
-        For example, a pattern to match an IPv4 address could be  written  like
+        For  example,  a pattern to match an IPv4 address could be written like
         this (ignore whitespace and line breaks):
           (?(DEFINE) (?<byte> 2[0-4]\d | 25[0-5] | 1\d\d | [1-9]?\d) )
           \b (?&byte) (\.(?&byte)){3} \b
-        The  first part of the pattern is a DEFINE group inside which a another
+        The first part of the pattern is a DEFINE group inside which a  another
-        group named "byte" is defined. This matches an individual component  of
+        group  named "byte" is defined. This matches an individual component of
-        an  IPv4  address  (a number less than 256). When matching takes place,
+        an IPv4 address (a number less than 256). When  matching  takes  place,
-        this part of the pattern is skipped because DEFINE acts  like  a  false
+        this  part  of  the pattern is skipped because DEFINE acts like a false
         condition.
         The rest of the pattern uses references to the named group to match the
-        four dot-separated components of an IPv4 address, insisting on  a  word
+        four  dot-separated  components of an IPv4 address, insisting on a word
         boundary at each end.
     Assertion conditions
-        If  the  condition  is  not  in any of the above formats, it must be an
+        If the condition is not in any of the above  formats,  it  must  be  an
-        assertion.  This may be a positive or negative lookahead or  lookbehind
+        assertion.   This may be a positive or negative lookahead or lookbehind
-        assertion.  Consider  this  pattern,  again  containing non-significant
+        assertion. Consider  this  pattern,  again  containing  non-significant
         white space, and with the two alternatives on the second line:
           (?(?=[^a-z]*[a-z])
           \d{2}-[a-z]{3}-\d{2}  |  \d{2}-\d{2}-\d{2} )
-        The condition  is  a  positive  lookahead  assertion  that  matches  an
+        The  condition  is  a  positive  lookahead  assertion  that  matches an
-        optional  sequence of non-letters followed by a letter. In other words,
+        optional sequence of non-letters followed by a letter. In other  words,
-        it tests for the presence of at least one letter in the subject.  If  a
+        it  tests  for the presence of at least one letter in the subject. If a
-        letter  is found, the subject is matched against the first alternative;
+        letter is found, the subject is matched against the first  alternative;
-        otherwise it is  matched  against  the  second.  This  pattern  matches
+        otherwise  it  is  matched  against  the  second.  This pattern matches
-        strings  in  one  of the two forms dd-aaa-dd or dd-dd-dd, where aaa are
+        strings in one of the two forms dd-aaa-dd or dd-dd-dd,  where  aaa  are
         letters and dd are digits.
  COMMENTS
-        The sequence (?# marks the start of a comment that continues up to  the
+        The  sequence (?# marks the start of a comment that continues up to the
-        next  closing  parenthesis.  Nested  parentheses are not permitted. The
+        next closing parenthesis. Nested parentheses  are  not  permitted.  The
-        characters that make up a comment play no part in the pattern  matching
+        characters  that make up a comment play no part in the pattern matching
         at all.
-        If  the PCRE_EXTENDED option is set, an unescaped # character outside a
+        If the PCRE_EXTENDED option is set, an unescaped # character outside  a
-        character class introduces a  comment  that  continues  to  immediately
+        character  class  introduces  a  comment  that continues to immediately
         after the next newline in the pattern.
  RECURSIVE PATTERNS
-        Consider  the problem of matching a string in parentheses, allowing for
+        Consider the problem of matching a string in parentheses, allowing  for
-        unlimited nested parentheses. Without the use of  recursion,  the  best
+        unlimited  nested  parentheses.  Without the use of recursion, the best
-        that  can  be  done  is  to use a pattern that matches up to some fixed
+        that can be done is to use a pattern that  matches  up  to  some  fixed
-        depth of nesting. It is not possible to  handle  an  arbitrary  nesting
+        depth  of  nesting.  It  is not possible to handle an arbitrary nesting
         depth.
         For some time, Perl has provided a facility that allows regular expres-
-        sions to recurse (amongst other things). It does this by  interpolating
+        sions  to recurse (amongst other things). It does this by interpolating
-        Perl  code in the expression at run time, and the code can refer to the
+        Perl code in the expression at run time, and the code can refer to  the
         expression itself. A Perl pattern using code interpolation to solve the
         parentheses problem can be created like this:
-Line 4404 
 RECURSIVE PATTERNS
+Line 4463 
 RECURSIVE PATTERNS
         refers recursively to the pattern in which it appears.
         Obviously, PCRE cannot support the interpolation of Perl code. Instead,
-        it  supports  special  syntax  for recursion of the entire pattern, and
+        it supports special syntax for recursion of  the  entire  pattern,  and
-        also for individual subpattern recursion.  After  its  introduction  in
+        also  for  individual  subpattern  recursion. After its introduction in
-        PCRE  and  Python,  this  kind of recursion was introduced into Perl at
+        PCRE and Python, this kind of recursion was  introduced  into  Perl  at
         release 5.10.
-        A special item that consists of (? followed by a  number  greater  than
+        A  special  item  that consists of (? followed by a number greater than
         zero and a closing parenthesis is a recursive call of the subpattern of
-        the given number, provided that it occurs inside that  subpattern.  (If
+        the  given  number, provided that it occurs inside that subpattern. (If
-        not,  it  is  a  "subroutine" call, which is described in the next sec-
+        not, it is a "subroutine" call, which is described  in  the  next  sec-
-        tion.) The special item (?R) or (?0) is a recursive call of the  entire
+        tion.)  The special item (?R) or (?0) is a recursive call of the entire
         regular expression.
-        In  PCRE (like Python, but unlike Perl), a recursive subpattern call is
+        In PCRE (like Python, but unlike Perl), a recursive subpattern call  is
         always treated as an atomic group. That is, once it has matched some of
         the subject string, it is never re-entered, even if it contains untried
         alternatives and there is a subsequent matching failure.
-        This PCRE pattern solves the nested  parentheses  problem  (assume  the
+        This  PCRE  pattern  solves  the nested parentheses problem (assume the
         PCRE_EXTENDED option is set so that white space is ignored):
           \( ( (?>[^()]+) | (?R) )* \)
-        First  it matches an opening parenthesis. Then it matches any number of
+        First it matches an opening parenthesis. Then it matches any number  of
-        substrings which can either be a  sequence  of  non-parentheses,  or  a
+        substrings  which  can  either  be  a sequence of non-parentheses, or a
-        recursive  match  of the pattern itself (that is, a correctly parenthe-
+        recursive match of the pattern itself (that is, a  correctly  parenthe-
         sized substring).  Finally there is a closing parenthesis.
-        If this were part of a larger pattern, you would not  want  to  recurse
+        If  this  were  part of a larger pattern, you would not want to recurse
         the entire pattern, so instead you could use this:
           ( \( ( (?>[^()]+) | (?1) )* \) )
-        We  have  put the pattern into parentheses, and caused the recursion to
+        We have put the pattern into parentheses, and caused the  recursion  to
         refer to them instead of the whole pattern.
-        In a larger pattern,  keeping  track  of  parenthesis  numbers  can  be
+        In  a  larger  pattern,  keeping  track  of  parenthesis numbers can be
-        tricky.  This is made easier by the use of relative references. (A Perl
+        tricky. This is made easier by the use of relative references. (A  Perl
-.10 feature.)  Instead of (?1) in the  pattern  above  you  can  write
+.10  feature.)   Instead  of  (?1)  in the pattern above you can write
         (?-2) to refer to the second most recently opened parentheses preceding
-        the recursion. In other  words,  a  negative  number  counts  capturing
+        the  recursion.  In  other  words,  a  negative number counts capturing
         parentheses leftwards from the point at which it is encountered.
-        It  is  also  possible  to refer to subsequently opened parentheses, by
+        It is also possible to refer to  subsequently  opened  parentheses,  by
-        writing references such as (?+2). However, these  cannot  be  recursive
+        writing  references  such  as (?+2). However, these cannot be recursive
-        because  the  reference  is  not inside the parentheses that are refer-
+        because the reference is not inside the  parentheses  that  are  refer-
-        enced. They are always "subroutine" calls, as  described  in  the  next
+        enced.  They  are  always  "subroutine" calls, as described in the next
         section.
-        An  alternative  approach is to use named parentheses instead. The Perl
+        An alternative approach is to use named parentheses instead.  The  Perl
-        syntax for this is (?&name); PCRE's earlier syntax  (?P>name)  is  also
+        syntax  for  this  is (?&name); PCRE's earlier syntax (?P>name) is also
         supported. We could rewrite the above example as follows:
           (?<pn> \( ( (?>[^()]+) | (?&pn) )* \) )
-        If  there  is more than one subpattern with the same name, the earliest
+        If there is more than one subpattern with the same name,  the  earliest
         one is used.
-        This particular example pattern that we have been looking  at  contains
+        This  particular  example pattern that we have been looking at contains
-        nested  unlimited repeats, and so the use of atomic grouping for match-
+        nested unlimited repeats, and so the use of atomic grouping for  match-
-        ing strings of non-parentheses is important when applying  the  pattern
+        ing  strings  of non-parentheses is important when applying the pattern
         to strings that do not match. For example, when this pattern is applied
         to
           (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa()
-        it yields "no match" quickly. However, if atomic grouping is not  used,
+        it  yields "no match" quickly. However, if atomic grouping is not used,
-        the  match  runs  for a very long time indeed because there are so many
+        the match runs for a very long time indeed because there  are  so  many
-        different ways the + and * repeats can carve up the  subject,  and  all
+        different  ways  the  + and * repeats can carve up the subject, and all
         have to be tested before failure can be reported.
         At the end of a match, the values set for any capturing subpatterns are
         those from the outermost level of the recursion at which the subpattern
-        value  is  set.   If  you want to obtain intermediate values, a callout
+        value is set.  If you want to obtain  intermediate  values,  a  callout
-        function can be used (see below and the pcrecallout documentation).  If
+        function  can be used (see below and the pcrecallout documentation). If
         the pattern above is matched against
           (ab(cd)ef)
-        the  value  for  the  capturing  parentheses is "ef", which is the last
+        the value for the capturing parentheses is  "ef",  which  is  the  last
-        value taken on at the top level. If additional parentheses  are  added,
+        value  taken  on at the top level. If additional parentheses are added,
         giving
           \( ( ( (?>[^()]+) | (?R) )* ) \)
              ^                        ^
              ^                        ^
-        the  string  they  capture is "ab(cd)ef", the contents of the top level
+        the string they capture is "ab(cd)ef", the contents of  the  top  level
-        parentheses. If there are more than 15 capturing parentheses in a  pat-
+        parentheses.  If there are more than 15 capturing parentheses in a pat-
         tern, PCRE has to obtain extra memory to store data during a recursion,
-        which it does by using pcre_malloc, freeing  it  via  pcre_free  after-
+        which  it  does  by  using pcre_malloc, freeing it via pcre_free after-
-        wards.  If  no  memory  can  be  obtained,  the  match  fails  with the
+        wards. If  no  memory  can  be  obtained,  the  match  fails  with  the
         PCRE_ERROR_NOMEMORY error.
-        Do not confuse the (?R) item with the condition (R),  which  tests  for
+        Do  not  confuse  the (?R) item with the condition (R), which tests for
-        recursion.   Consider  this pattern, which matches text in angle brack-
+        recursion.  Consider this pattern, which matches text in  angle  brack-
-        ets, allowing for arbitrary nesting. Only digits are allowed in  nested
+        ets,  allowing for arbitrary nesting. Only digits are allowed in nested
-        brackets  (that is, when recursing), whereas any characters are permit-
+        brackets (that is, when recursing), whereas any characters are  permit-
         ted at the outer level.
           < (?: (?(R) \d++  | [^<>]*+) | (?R)) * >
-        In this pattern, (?(R) is the start of a conditional  subpattern,  with
+        In  this  pattern, (?(R) is the start of a conditional subpattern, with
-        two  different  alternatives for the recursive and non-recursive cases.
+        two different alternatives for the recursive and  non-recursive  cases.
         The (?R) item is the actual recursive call.
  SUBPATTERNS AS SUBROUTINES
         If the syntax for a recursive subpattern reference (either by number or
-        by  name)  is used outside the parentheses to which it refers, it oper-
+        by name) is used outside the parentheses to which it refers,  it  oper-
-        ates like a subroutine in a programming language. The "called"  subpat-
+        ates  like a subroutine in a programming language. The "called" subpat-
         tern may be defined before or after the reference. A numbered reference
         can be absolute or relative, as in these examples:
-Line 4526 
 SUBPATTERNS AS SUBROUTINES
+Line 4585 
 SUBPATTERNS AS SUBROUTINES
           (sens|respons)e and \1ibility
-        matches "sense and sensibility" and "response and responsibility",  but
+        matches  "sense and sensibility" and "response and responsibility", but
         not "sense and responsibility". If instead the pattern
           (sens|respons)e and (?1)ibility
-        is  used, it does match "sense and responsibility" as well as the other
+        is used, it does match "sense and responsibility" as well as the  other
-        two strings. Another example is  given  in  the  discussion  of  DEFINE
+        two  strings.  Another  example  is  given  in the discussion of DEFINE
         above.
         Like recursive subpatterns, a "subroutine" call is always treated as an
-        atomic group. That is, once it has matched some of the subject  string,
+        atomic  group. That is, once it has matched some of the subject string,
-        it  is  never  re-entered, even if it contains untried alternatives and
+        it is never re-entered, even if it contains  untried  alternatives  and
         there is a subsequent matching failure.
-        When a subpattern is used as a subroutine, processing options  such  as
+        When  a  subpattern is used as a subroutine, processing options such as
         case-independence are fixed when the subpattern is defined. They cannot
         be changed for different calls. For example, consider this pattern:
           (abc)(?i:(?-1))
-        It matches "abcabc". It does not match "abcABC" because the  change  of
+        It  matches  "abcabc". It does not match "abcABC" because the change of
         processing option does not affect the called subpattern.
  CALLOUTS
         Perl has a feature whereby using the sequence (?{...}) causes arbitrary
-        Perl code to be obeyed in the middle of matching a regular  expression.
+        Perl  code to be obeyed in the middle of matching a regular expression.
         This makes it possible, amongst other things, to extract different sub-
         strings that match the same pair of parentheses when there is a repeti-
         tion.
         PCRE provides a similar feature, but of course it cannot obey arbitrary
         Perl code. The feature is called "callout". The caller of PCRE provides
-        an  external function by putting its entry point in the global variable
+        an external function by putting its entry point in the global  variable
-        pcre_callout.  By default, this variable contains NULL, which  disables
+        pcre_callout.   By default, this variable contains NULL, which disables
         all calling out.
-        Within  a  regular  expression,  (?C) indicates the points at which the
+        Within a regular expression, (?C) indicates the  points  at  which  the
-        external function is to be called. If you want  to  identify  different
+        external  function  is  to be called. If you want to identify different
-        callout  points, you can put a number less than 256 after the letter C.
+        callout points, you can put a number less than 256 after the letter  C.
-        The default value is zero.  For example, this pattern has  two  callout
+        The  default  value is zero.  For example, this pattern has two callout
         points:
           (?C1)abc(?C2)def
         If the PCRE_AUTO_CALLOUT flag is passed to pcre_compile(), callouts are
-        automatically installed before each item in the pattern. They  are  all
+        automatically  installed  before each item in the pattern. They are all
         numbered 255.
         During matching, when PCRE reaches a callout point (and pcre_callout is
-        set), the external function is called. It is provided with  the  number
+        set),  the  external function is called. It is provided with the number
-        of  the callout, the position in the pattern, and, optionally, one item
+        of the callout, the position in the pattern, and, optionally, one  item
-        of data originally supplied by the caller of pcre_exec().  The  callout
+        of  data  originally supplied by the caller of pcre_exec(). The callout
-        function  may cause matching to proceed, to backtrack, or to fail alto-
+        function may cause matching to proceed, to backtrack, or to fail  alto-
         gether. A complete description of the interface to the callout function
         is given in the pcrecallout documentation.
  BACTRACKING CONTROL
-        Perl  5.10 introduced a number of "Special Backtracking Control Verbs",
+        Perl 5.10 introduced a number of "Special Backtracking Control  Verbs",
         which are described in the Perl documentation as "experimental and sub-
-        ject  to  change or removal in a future version of Perl". It goes on to
+        ject to change or removal in a future version of Perl". It goes  on  to
-        say: "Their usage in production code should be noted to avoid  problems
+        say:  "Their usage in production code should be noted to avoid problems
         during upgrades." The same remarks apply to the PCRE features described
         in this section.
         Since these verbs are specifically related to backtracking, they can be
-        used  only  when  the pattern is to be matched using pcre_exec(), which
+        used only when the pattern is to be matched  using  pcre_exec(),  which
-        uses a backtracking algorithm. They cause an error  if  encountered  by
+        uses  a  backtracking  algorithm. They cause an error if encountered by
         pcre_dfa_exec().
-        The  new verbs make use of what was previously invalid syntax: an open-
+        The new verbs make use of what was previously invalid syntax: an  open-
         ing parenthesis followed by an asterisk. In Perl, they are generally of
         the form (*VERB:ARG) but PCRE does not support the use of arguments, so
-        its general form is just (*VERB). Any number of these verbs  may  occur
+        its  general  form is just (*VERB). Any number of these verbs may occur
         in a pattern. There are two kinds:
     Verbs that act immediately
-Line 4611 
 BACTRACKING CONTROL
+Line 4670 
 BACTRACKING CONTROL
            (*ACCEPT)
-        This  verb causes the match to end successfully, skipping the remainder
+        This verb causes the match to end successfully, skipping the  remainder
-        of the pattern. When inside a recursion, only the innermost pattern  is
+        of  the pattern. When inside a recursion, only the innermost pattern is
-        ended  immediately.  PCRE  differs  from  Perl  in  what happens if the
+        ended immediately. PCRE differs  from  Perl  in  what  happens  if  the
-        (*ACCEPT) is inside capturing parentheses. In Perl, the data so far  is
+        (*ACCEPT)  is inside capturing parentheses. In Perl, the data so far is
         captured: in PCRE no data is captured. For example:
           A(A|B(*ACCEPT)|C)D
-        This  matches  "AB", "AAD", or "ACD", but when it matches "AB", no data
+        This matches "AB", "AAD", or "ACD", but when it matches "AB",  no  data
         is captured.
           (*FAIL) or (*F)
-        This verb causes the match to fail, forcing backtracking to  occur.  It
+        This  verb  causes the match to fail, forcing backtracking to occur. It
-        is  equivalent to (?!) but easier to read. The Perl documentation notes
+        is equivalent to (?!) but easier to read. The Perl documentation  notes
-        that it is probably useful only when combined  with  (?{})  or  (??{}).
+        that  it  is  probably  useful only when combined with (?{}) or (??{}).
-        Those  are,  of course, Perl features that are not present in PCRE. The
+        Those are, of course, Perl features that are not present in  PCRE.  The
-        nearest equivalent is the callout feature, as for example in this  pat-
+        nearest  equivalent is the callout feature, as for example in this pat-
         tern:
           a+(?C)(*FAIL)
-        A  match  with the string "aaaa" always fails, but the callout is taken
+        A match with the string "aaaa" always fails, but the callout  is  taken
         before each backtrack happens (in this example, 10 times).
     Verbs that act after backtracking
         The following verbs do nothing when they are encountered. Matching con-
-        tinues  with what follows, but if there is no subsequent match, a fail-
+        tinues with what follows, but if there is no subsequent match, a  fail-
-        ure is forced.  The verbs  differ  in  exactly  what  kind  of  failure
+        ure  is  forced.   The  verbs  differ  in  exactly what kind of failure
         occurs.
           (*COMMIT)
-        This  verb  causes  the whole match to fail outright if the rest of the
+        This verb causes the whole match to fail outright if the  rest  of  the
-        pattern does not match. Even if the pattern is unanchored,  no  further
+        pattern  does  not match. Even if the pattern is unanchored, no further
-        attempts  to find a match by advancing the start point take place. Once
+        attempts to find a match by advancing the start point take place.  Once
-        (*COMMIT) has been passed, pcre_exec() is committed to finding a  match
+        (*COMMIT)  has been passed, pcre_exec() is committed to finding a match
         at the current starting point, or not at all. For example:
           a+(*COMMIT)b
-        This  matches  "xxaab" but not "aacaab". It can be thought of as a kind
+        This matches "xxaab" but not "aacaab". It can be thought of as  a  kind
         of dynamic anchor, or "I've started, so I must finish."
           (*PRUNE)
-        This verb causes the match to fail at the current position if the  rest
+        This  verb causes the match to fail at the current position if the rest
         of the pattern does not match. If the pattern is unanchored, the normal
-        "bumpalong" advance to the next starting character then happens.  Back-
+        "bumpalong"  advance to the next starting character then happens. Back-
-        tracking  can  occur as usual to the left of (*PRUNE), or when matching
+        tracking can occur as usual to the left of (*PRUNE), or  when  matching
-        to the right of (*PRUNE), but if there is no match to the right,  back-
+        to  the right of (*PRUNE), but if there is no match to the right, back-
-        tracking  cannot  cross (*PRUNE).  In simple cases, the use of (*PRUNE)
+        tracking cannot cross (*PRUNE).  In simple cases, the use  of  (*PRUNE)
         is just an alternative to an atomic group or possessive quantifier, but
-        there  are  some uses of (*PRUNE) that cannot be expressed in any other
+        there are some uses of (*PRUNE) that cannot be expressed in  any  other
         way.
           (*SKIP)
-        This verb is like (*PRUNE), except that if the pattern  is  unanchored,
+        This  verb  is like (*PRUNE), except that if the pattern is unanchored,
-        the  "bumpalong" advance is not to the next character, but to the posi-
+        the "bumpalong" advance is not to the next character, but to the  posi-
-        tion in the subject where (*SKIP) was  encountered.  (*SKIP)  signifies
+        tion  in  the  subject where (*SKIP) was encountered. (*SKIP) signifies
-        that  whatever  text  was  matched leading up to it cannot be part of a
+        that whatever text was matched leading up to it cannot  be  part  of  a
         successful match. Consider:
           a+(*SKIP)b
-        If the subject is "aaaac...",  after  the  first  match  attempt  fails
+        If  the  subject  is  "aaaac...",  after  the first match attempt fails
-        (starting  at  the  first  character in the string), the starting point
+        (starting at the first character in the  string),  the  starting  point
         skips on to start the next attempt at "c". Note that a possessive quan-
-        tifer  does not have the same effect in this example; although it would
+        tifer does not have the same effect in this example; although it  would
-        suppress backtracking  during  the  first  match  attempt,  the  second
+        suppress  backtracking  during  the  first  match  attempt,  the second
-        attempt  would  start at the second character instead of skipping on to
+        attempt would start at the second character instead of skipping  on  to
         "c".
           (*THEN)
         This verb causes a skip to the next alternation if the rest of the pat-
         tern does not match. That is, it cancels pending backtracking, but only
-        within the current alternation. Its name  comes  from  the  observation
+        within  the  current  alternation.  Its name comes from the observation
         that it can be used for a pattern-based if-then-else block:
           ( COND1 (*THEN) FOO | COND2 (*THEN) BAR | COND3 (*THEN) BAZ ) ...
-        If  the COND1 pattern matches, FOO is tried (and possibly further items
+        If the COND1 pattern matches, FOO is tried (and possibly further  items
-        after the end of the group if FOO succeeds);  on  failure  the  matcher
+        after  the  end  of  the group if FOO succeeds); on failure the matcher
-        skips  to  the second alternative and tries COND2, without backtracking
+        skips to the second alternative and tries COND2,  without  backtracking
-        into COND1. If (*THEN) is used outside  of  any  alternation,  it  acts
+        into  COND1.  If  (*THEN)  is  used outside of any alternation, it acts
         exactly like (*PRUNE).
-Line 4716 
 AUTHOR
+Line 4775 
 AUTHOR
  REVISION
-        Last updated: 09 August 2007
+        Last updated: 21 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 5013 
 BACKTRACKING CONTROL
+Line 5072 
 BACKTRACKING CONTROL
           (*THEN)        local failure, backtrack to next alternation
+ NEWLINE CONVENTIONS
+        These are recognized only at the very start of a pattern.
+          (*CR)
+          (*LF)
+          (*CRLF)
+          (*ANYCRLF)
+          (*ANY)
  CALLOUTS
           (?C)      callout
-Line 5033 
 AUTHOR
+Line 5103 
 AUTHOR
  REVISION
-        Last updated: 08 August 2007
+        Last updated: 21 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------

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