From: Johan Vromans <jvromans@squirrel.nl>
Date: Sun, 9 Jun 2002 13:12:43 +0000 (+0200)
Subject: [Patch] $^N issues
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=77ea4f6d93da91f08d36b99d2fc1b3f43e33aab0;p=p5sagit%2Fp5-mst-13.2.git

[Patch] $^N issues
Message-ID: <15619.14379.888034.910020@phoenix.squirrel.nl>

p4raw-id: //depot/perl@17131
---

diff --git a/lib/English.pm b/lib/English.pm
index 5383368..05dd05c 100644
--- a/lib/English.pm
+++ b/lib/English.pm
@@ -124,6 +124,7 @@ sub import {
 	*OSNAME
 	*LAST_REGEXP_CODE_RESULT
 	*EXCEPTIONS_BEING_CAUGHT
+	*LAST_SUBMATCH_RESULT
 	@LAST_MATCH_START
 	@LAST_MATCH_END
 );
@@ -144,6 +145,7 @@ sub import {
 # Matching.
 
 	*LAST_PAREN_MATCH			= \$+	;
+	*LAST_SUBMATCH_RESULT			= \$^N ;
 	*LAST_MATCH_START			= \@- ;
 	*LAST_MATCH_END				= \@+ ;
 
diff --git a/pod/perlre.pod b/pod/perlre.pod
index c0d4e89..0256f22 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<perlsyn/"Compound Statements">.)
 
@@ -563,6 +566,14 @@ This zero-width assertion evaluate any embedded Perl code.  It
 always succeeds, and its C<code> is not interpolated.  Currently,
 the rules to determine where the C<code> 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<code> is properly scoped in the following sense: If the assertion
 is backtracked (compare L<"Backtracking">), all changes introduced after
 C<local>ization are undone, so that