Re^4: What's the deal with apostrophes?

[dsheroh]

in reply to Re^3: What's the deal with apostrophes?
in thread What's the deal with apostrophes?

It seems a little odd to me to just change characters for something like that and expect perl to "know" that's what they are there for. Does it really work that way?

Yes, it does really work that way... more or less.

The one catch is that, when you use alternate delimiters, you have to explicitly use either "m" or "s" at the beginning of the regex. The "m" and "s" are the actual operators which (in the right context) trigger a regex operation, so when perl sees those followed by punctuation, it recognizes that the punctuation used will be the delimiter for that regex without needing to expicitly set or reset anything.

So, for example, all of these variations are equivalent:

#!/usr/bin/perl

use strict;
use warnings;

my $text = 'This is a text string.';

print $text =~ m/is a/, " - m//\n";

# Default delimiter, so the "m" can be omitted
print $text =~ /is a/, " - //\n";

# Custom delimiters, so the "m" is mandatory
print $text =~ m#is a#, " - m##\n";
print $text =~ m!is a!, " - m!!\n";
print $text =~ m^is a^, " - m^^\n";

# Open/close punctuation is used in pairs
print $text =~ m[is a], " - m[]\n";
print $text =~ m(is a), " - m()\n";
print $text =~ m<is a>, " - m<>\n";

The print on each regex displays the number of matches found along with the delimiters used:

1 - m//
1 - //
1 - m##
1 - m!!
1 - m^^
1 - m[]
1 - m()
1 - m<>

[tallCoolOne]

That is about the coolest thing I've seen in perl since ice cubes. Pretty amazing really.
Thanks! That's one of the most helpful, useful tips that I have gotten here. This will make for a lot of simplifying changes in my code from now on.
*bows in respect and wonderment at the awesomeness of perl, and the generosity of the monks*