From 77ea4f6d93da91f08d36b99d2fc1b3f43e33aab0 Mon Sep 17 00:00:00 2001 From: Johan Vromans Date: Sun, 9 Jun 2002 15:12:43 +0200 Subject: [Patch] $^N issues Message-ID: <15619.14379.888034.910020@phoenix.squirrel.nl> p4raw-id: //depot/perl@17131 --- pod/perlre.pod | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'pod') diff --git a/pod/perlre.pod b/pod/perlre.pod index c0d4e8955b..0256f225f3 100644 --- a/pod/perlre.pod +++ b/pod/perlre.pod @@ -392,11 +392,14 @@ Several special variables also refer back to portions of the previous match. C<$+> returns whatever the last bracket match matched. C<$&> returns the entire matched string. (At one point C<$0> did also, but now it returns the name of the program.) C<$`> returns -everything before the matched string. And C<$'> returns everything -after the matched string. +everything before the matched string. C<$'> returns everything +after the matched string. And C<$^N> contains whatever was matched by +the most-recently closed group (submatch). C<$^N> can be used in +extended patterns (see below), for example to assign a submatch to a +variable. The numbered variables ($1, $2, $3, etc.) and the related punctuation -set (C<$+>, C<$&>, C<$`>, and C<$'>) are all dynamically scoped +set (C<$+>, C<$&>, C<$`>, C<$'>, and C<$^N>) are all dynamically scoped until the end of the enclosing block or until the next successful match, whichever comes first. (See L.) @@ -563,6 +566,14 @@ This zero-width assertion evaluate any embedded Perl code. It always succeeds, and its C is not interpolated. Currently, the rules to determine where the C ends are somewhat convoluted. +This feature can be used together with the special variable C<$^N> to +capture the results of submatches in variables without having to keep +track of the number of nested parentheses. For example: + + $_ = "The brown fox jumps over the lazy dog"; + /the (\S+)(?{ $color = $^N }) (\S+)(?{ $animal = $^N })/i; + print "color = $color, animal = $animal\n"; + The C is properly scoped in the following sense: If the assertion is backtracked (compare L<"Backtracking">), all changes introduced after Cization are undone, so that -- cgit v1.2.1