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Diffstat (limited to 'pod/perlre.pod')
| -rw-r--r-- | pod/perlre.pod | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/pod/perlre.pod b/pod/perlre.pod index a22344fe4b..f79b8c7b51 100644 --- a/pod/perlre.pod +++ b/pod/perlre.pod @@ -998,18 +998,28 @@ highly experimental, and may be changed or deleted without notice. Conditional expression. C<(condition)> should be either an integer in parentheses (which is valid if the corresponding pair of parentheses -matched), or look-ahead/look-behind/evaluate zero-width assertion. +matched), a look-ahead/look-behind/evaluate zero-width assertion, a +name in angle brackets or single quotes (which is valid if a buffer +with the given name matched), the special symbol (R) (true when +evaluated inside of recursion or eval). Additionally the R may be +followed by a number, (which will be true when evaluated when recursing +inside of the appropriate group), or by C<&NAME> in which case it will +be true only when evaluated during recursion into the named group. For example: - m{ ( \( )? - [^()]+ - (?(1) \) ) + m{ ( \( )? + [^()]+ + (?(1) \) ) }x matches a chunk of non-parentheses, possibly included in parentheses themselves. +An additional special form of this pattern is the DEFINE pattern, which +never executes its yes-pattern except by recursion, and does not allow +a no-pattern. + =back =head2 Backtracking |