Document usage of $_ and pos() inside /(?{...})/.

(see change #2367.)
p4raw-link: @2367 on //depot/perl: 9661b5442a5f8dacc64d54eb1de98575f21de5f2

p4raw-id: //depot/perl@22125

diff --git a/pod/perlre.pod b/pod/perlre.pod
index 365cbb9..ea88fc0 100644 (file)
--- a/pod/perlre.pod
+++ b/pod/perlre.pod
@@ -574,6 +574,10 @@ track of the number of nested parentheses. For example:
   /the (\S+)(?{ $color = $^N }) (\S+)(?{ $animal = $^N })/i;
   print "color = $color, animal = $animal\n";
 
+Inside the C<(?{...})> block, C<$_> refers to the string the regular
+expression is matching against. You can also use C<pos()> to know what is
+the current position of matching withing this string.
+
 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