I'm testing for apostrophes at the beginning (regex #1) and end (regex #2) of words. These two regexes behave as I expected, but when I combine them as alternatives in a single regex (regex #3), it completely fails to match.

(I'm not really looking for better ways to look for apostrophes, I just want to understand why if A is true, "A or B" isn't true.)

perl 5.34.0 

#!/usr/bin/env perl

use 5.010;
use warnings;
use strict;

my @frags = qw{
                  "'frags'"
                  "'frags
                  frags'.
                  frag's.
                  frags.
                  frags'
          };

for my $frag (@frags) {
    print  "{$frag} : ";

    if ($frag =~ /\W'\w/) {                            #1
        print 'matched by first regex. ';
    }
    if ($frag =~ /\w'\W/) {                            #2
        print 'matched by second regex. ';
    }
    if ($frag =~ /\W'\w | \w'\W/) {                #3
        print 'matched by third regex. ';
    }
    say '';
}

[download]
Result: 
{"'frags'"} : matched by first regex. matched by second regex.
{"'frags} : matched by first regex.
{frags'.} : matched by second regex.
{frag's.} :
{frags.} :
{frags'} :

[download]

In reply to Regex alternatives not behaving as expected by ibm1620

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