perlvar: 

               $` is the same as "substr($var, 0, $-[0])"
               $& is the same as "substr($var, $-[0], $+[0] - $-[0])"
               $' is the same as "substr($var, $+[0])"

[download]
So: 
sub  prematch (;$) { substr((@_ ? $_[0] : $_), 0, $-[0]) }
sub     match (;$) { substr((@_ ? $_[0] : $_), $-[0], $+[0] - $-[0]) }
sub postmatch (;$) { substr((@_ ? $_[0] : $_), $+[0]) }

my $foo = 'Hello, world!';
$foo =~ /o, w../;

$\ = "\n";
print  prematch($foo);
print     match($foo);
print postmatch($foo);

=head2 C<prematch>, C<match>, C<postmatch>

Like C<$`>, C<$&> and C<$'>, but not slowing down, and 
needing a single argument: the string on which the 
most recent regex was performed. Uses C<$_> when no
argument is given.

=cut

[download]
Update: s/the variable on which/the string on which/ 

- Yes, I reinvent wheels.
- Spam: Visit eurotraQ.

In reply to Re: Why can't $` $& $' be enabled on a per-regex basis? by Juerd
in thread Why can't $` $& $' be enabled on a per-regex basis? by MrNobo1024

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