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| author | Rafael Garcia-Suarez <rgarciasuarez@gmail.com> | 2006-10-26 16:11:26 +0000 |
|---|---|---|
| committer | Rafael Garcia-Suarez <rgarciasuarez@gmail.com> | 2006-10-26 16:11:26 +0000 |
| commit | 286f584ab7c58e3769088aa5b01f152848311dbc (patch) | |
| tree | 0d6adaaf1d58e1122e1484e603ad4628ac7e1ee5 /pod | |
| parent | 7f69552c33ff9bd1eb6665f732d0f22956ac2f30 (diff) | |
| download | perl-286f584ab7c58e3769088aa5b01f152848311dbc.tar.gz | |
Document the new (?FAIL) assertion (Yves Orton)
p4raw-id: //depot/perl@29119
Diffstat (limited to 'pod')
| -rw-r--r-- | pod/perlre.pod | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/pod/perlre.pod b/pod/perlre.pod index 1a95297919..b46b3811d0 100644 --- a/pod/perlre.pod +++ b/pod/perlre.pod @@ -933,6 +933,15 @@ the same name, then it recurses to the leftmost. It is an error to refer to a name that is not declared somewhere in the pattern. +=item C<(?FAIL)> C<(?F)> +X<(?FAIL)> X<(?F)> + +This pattern matches nothing and always fails. It can be used to force the +engine to backtrack. It is equivalent to C<(?!)>, but easier to read. In +fact, C<(?!)> gets optimised into C<(?FAIL)> internally. + +It is probably useful only when combined with C<(?{})> or C<(??{})>. + =item C<< (?>pattern) >> X<backtrack> X<backtracking> X<atomic> X<possessive> |