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23. The tests have been re-organized, adding tests 11 and 12, to make it |
23. The tests have been re-organized, adding tests 11 and 12, to make it |
| 132 |
possible to check the Perl 5.10 features against Perl 5.10. |
possible to check the Perl 5.10 features against Perl 5.10. |
| 133 |
|
|
| 134 |
|
24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine |
| 135 |
|
pattern matches a fixed length string. PCRE did not allow this; now it |
| 136 |
|
does. Neither allows recursion. |
| 137 |
|
|
| 138 |
|
25. I finally figured out how to implement a request to provide the minimum |
| 139 |
|
length of subject string that was needed in order to match a given pattern. |
| 140 |
|
(It was back references and recursion that I had previously got hung up |
| 141 |
|
on.) This code has now been added to pcre_study(); it finds a lower bound |
| 142 |
|
to the length of subject needed. It is not necessarily the greatest lower |
| 143 |
|
bound, but using it to avoid searching strings that are too short does give |
| 144 |
|
some useful speed-ups. The value is available to calling programs via |
| 145 |
|
pcre_fullinfo(). |
| 146 |
|
|
| 147 |
|
26. While implementing 25, I discovered to my embarrassment that pcretest had |
| 148 |
|
not been passing the result of pcre_study() to pcre_dfa_exec(), so the |
| 149 |
|
study optimizations had never been tested with that matching function. |
| 150 |
|
Oops. What is worse, even when it was passed study data, there was a bug in |
| 151 |
|
pcre_dfa_exec() that meant it never actually used it. Double oops. There |
| 152 |
|
were also very few tests of studied patterns with pcre_dfa_exec(). |
| 153 |
|
|
| 154 |
|
27. If (?| is used to create subpatterns with duplicate numbers, they are now |
| 155 |
|
allowed to have the same name, even if PCRE_DUPNAMES is not set. However, |
| 156 |
|
on the other side of the coin, they are no longer allowed to have different |
| 157 |
|
names, because these cannot be distinguished in PCRE, and this has caused |
| 158 |
|
confusion. (This is a difference from Perl.) |
| 159 |
|
|
| 160 |
|
28. When duplicate subpattern names are present (necessarily with different |
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numbers, as required by 27 above), and a test is made by name in a |
| 162 |
|
conditional pattern, either for a subpattern having been matched, or for |
| 163 |
|
recursion in such a pattern, all the associated numbered subpatterns are |
| 164 |
|
tested, and the overall condition is true if the condition is true for any |
| 165 |
|
one of them. This is the way Perl works, and is also more like the way |
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|
testing by number works. |
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|
| 168 |
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|
| 169 |
Version 7.9 11-Apr-09 |
Version 7.9 11-Apr-09 |
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--------------------- |
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