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revision 83 by nigel, Sat Feb 24 21:41:06 2007 UTC revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC
# Line 156  If PCRE is built with Unicode character Line 156  If PCRE is built with Unicode character
156  support), the escape sequences \p{..}, \P{..}, and \X are supported.  support), the escape sequences \p{..}, \P{..}, and \X are supported.
157  The available properties that can be tested are limited to the general  The available properties that can be tested are limited to the general
158  category properties such as Lu for an upper case letter or Nd for a decimal  category properties such as Lu for an upper case letter or Nd for a decimal
159  number. A full list is given in the  number, the Unicode script names such as Arabic or Han, and the derived
160    properties Any and L&. A full list is given in the
161  <a href="pcrepattern.html"><b>pcrepattern</b></a>  <a href="pcrepattern.html"><b>pcrepattern</b></a>
162  documentation. The PCRE library is increased in size by about 90K when Unicode  documentation. Only the short names for properties are supported. For example,
163  property support is included.  \p{L} matches a letter. Its Perl synonym, \p{Letter}, is not supported.
164    Furthermore, in Perl, many properties may optionally be prefixed by "Is", for
165    compatibility with Perl 5.6. PCRE does not support this.
166  </P>  </P>
167  <P>  <P>
168  The following comments apply when PCRE is running in UTF-8 mode:  The following comments apply when PCRE is running in UTF-8 mode:
# Line 177  PCRE when PCRE_NO_UTF8_CHECK is set, the Line 180  PCRE when PCRE_NO_UTF8_CHECK is set, the
180  may crash.  may crash.
181  </P>  </P>
182  <P>  <P>
183  2. In a pattern, the escape sequence \x{...}, where the contents of the braces  2. An unbraced hexadecimal escape sequence (such as \xb3) matches a two-byte
184  is a string of hexadecimal digits, is interpreted as a UTF-8 character whose  UTF-8 character if the value is greater than 127.
 code number is the given hexadecimal number, for example: \x{1234}. If a  
 non-hexadecimal digit appears between the braces, the item is not recognized.  
 This escape sequence can be used either as a literal, or within a character  
 class.  
185  </P>  </P>
186  <P>  <P>
187  3. The original hexadecimal escape sequence, \xhh, matches a two-byte UTF-8  3. Repeat quantifiers apply to complete UTF-8 characters, not to individual
 character if the value is greater than 127.  
 </P>  
 <P>  
 4. Repeat quantifiers apply to complete UTF-8 characters, not to individual  
188  bytes, for example: \x{100}{3}.  bytes, for example: \x{100}{3}.
189  </P>  </P>
190  <P>  <P>
191  5. The dot metacharacter matches one UTF-8 character instead of a single byte.  4. The dot metacharacter matches one UTF-8 character instead of a single byte.
192  </P>  </P>
193  <P>  <P>
194  6. The escape sequence \C can be used to match a single byte in UTF-8 mode,  5. The escape sequence \C can be used to match a single byte in UTF-8 mode,
195  but its use can lead to some strange effects. This facility is not available in  but its use can lead to some strange effects. This facility is not available in
196  the alternative matching function, <b>pcre_dfa_exec()</b>.  the alternative matching function, <b>pcre_dfa_exec()</b>.
197  </P>  </P>
198  <P>  <P>
199  7. The character escapes \b, \B, \d, \D, \s, \S, \w, and \W correctly  6. The character escapes \b, \B, \d, \D, \s, \S, \w, and \W correctly
200  test characters of any code value, but the characters that PCRE recognizes as  test characters of any code value, but the characters that PCRE recognizes as
201  digits, spaces, or word characters remain the same set as before, all with  digits, spaces, or word characters remain the same set as before, all with
202  values less than 256. This remains true even when PCRE includes Unicode  values less than 256. This remains true even when PCRE includes Unicode
# Line 210  cases. If you really want to test for a Line 205  cases. If you really want to test for a
205  must use Unicode property tests such as \p{Nd}.  must use Unicode property tests such as \p{Nd}.
206  </P>  </P>
207  <P>  <P>
208  8. Similarly, characters that match the POSIX named character classes are all  7. Similarly, characters that match the POSIX named character classes are all
209  low-valued characters.  low-valued characters.
210  </P>  </P>
211  <P>  <P>
212  9. Case-insensitive matching applies only to characters whose values are less  8. Case-insensitive matching applies only to characters whose values are less
213  than 128, unless PCRE is built with Unicode property support. Even when Unicode  than 128, unless PCRE is built with Unicode property support. Even when Unicode
214  property support is available, PCRE still uses its own character tables when  property support is available, PCRE still uses its own character tables when
215  checking the case of low-valued characters, so as not to degrade performance.  checking the case of low-valued characters, so as not to degrade performance.
216  The Unicode property information is used only for characters with higher  The Unicode property information is used only for characters with higher
217  values.  values. Even when Unicode property support is available, PCRE supports
218    case-insensitive matching only when there is a one-to-one mapping between a
219    letter's cases. There are a small number of many-to-one mappings in Unicode;
220    these are not supported by PCRE.
221  </P>  </P>
222  <br><a name="SEC5" href="#TOC1">AUTHOR</a><br>  <br><a name="SEC5" href="#TOC1">AUTHOR</a><br>
223  <P>  <P>
# Line 233  Cambridge CB2 3QG, England. Line 231  Cambridge CB2 3QG, England.
231  Putting an actual email address here seems to have been a spam magnet, so I've  Putting an actual email address here seems to have been a spam magnet, so I've
232  taken it away. If you want to email me, use my initial and surname, separated  taken it away. If you want to email me, use my initial and surname, separated
233  by a dot, at the domain ucs.cam.ac.uk.  by a dot, at the domain ucs.cam.ac.uk.
234  Last updated: 07 March 2005  Last updated: 24 January 2006
235  <br>  <br>
236  Copyright &copy; 1997-2005 University of Cambridge.  Copyright &copy; 1997-2006 University of Cambridge.
237  <p>  <p>
238  Return to the <a href="index.html">PCRE index page</a>.  Return to the <a href="index.html">PCRE index page</a>.
239  </p>  </p>
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