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| author | Moritz Lenz <moritz@faui2k3.org> | 2009-11-27 00:33:09 +0100 |
|---|---|---|
| committer | Rafael Garcia-Suarez <rgs@consttype.org> | 2009-11-28 18:35:31 +0100 |
| commit | 408633379a1452b4e14d7c3b5e80f7dc05ea7986 (patch) | |
| tree | c44763a814659f5e8eae84a48c2e8c898a4f19cc /pod | |
| parent | 17c59fdf7540adaf656e96fe6d48b58dab391dc0 (diff) | |
| download | perl-408633379a1452b4e14d7c3b5e80f7dc05ea7986.tar.gz | |
Document backreferences to groups that did not match
Also add a test for that, fill in test description, and sneak in a vim
modeline for re_tests
Diffstat (limited to 'pod')
| -rw-r--r-- | pod/perlre.pod | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/pod/perlre.pod b/pod/perlre.pod index df627ff012..42017ddf66 100644 --- a/pod/perlre.pod +++ b/pod/perlre.pod @@ -518,6 +518,10 @@ backreference only if at least 11 left parentheses have opened before it. And so on. \1 through \9 are always interpreted as backreferences. +If the bracketing group did not match, the associated backreference won't +match either. (This can happen if the bracketing group is optional, or +in a different branch of an alternation.) + X<\g{1}> X<\g{-1}> X<\g{name}> X<relative backreference> X<named backreference> In order to provide a safer and easier way to construct patterns using backreferences, Perl provides the C<\g{N}> notation (starting with perl |