Ever since I've read Obfuscated regexp, I've been trying to figure out how to create a global regex using (?{ }) as opposed to m//g. I've spent awhile looking at the code and refractoring it, but I still can't seem to figure out why this iterates:

qr/<([\w\d]+)\s+(?{ print $^N })\s*?>/;

I've passed the code through use re qw/debug/; and YAPE::Regex::Explain, which rewrote the regex:

(?-imsx:<([\w\d]+)\s+(?{ print $^N })\s*?>)

Yet while I (believe I) understand how the first match is made, I still cannot seem to figure out why subsequent matches occur.

I've tried creating simplified regexes to illustrate the idiom:

#!/usr/bin/perl -w
use strict;

my $s = "abacada";               # 'bcd' delimited by 'a'
print $s =~ /[^a]/g;             # prints 'bcd'
$s =~ /([^a])(?{ print $^N })/;  # prints 'b'

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However I cannot seem to duplicate the functionality with a terse example as my attempts have only returned the first match (as use re qw/debug/; confirms). While the reason for this behavior is fairly obvious given the regex, it underscores the fact that I have yet to grasp how the first code iterates.

Can someone please elucidate what I'm missing so that I might progress along the path of enlightment?

In reply to Global Regex sans //g by eibwen

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