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abra abra - 8 months ago 41
Perl Question

Why does smartmatch return false when I match against a regex containing slashes?

I'm trying to match a simple string against a regular expression pattern using the smartmatch operator:

#!/usr/bin/env perl

use strict;
use warnings;
use utf8;
use open qw(:std :utf8);

my $name = qr{/(\w+)/};
my $line = 'string';

print "ok\n" if $line ~~ /$name/;

I expect this to print "ok", but it doesn't. Why not?


Remove the slashes from your regex:

my $name = qr{(\w+)};

Since you're wrapping the regular expression in qr{}, everything inside the braces is being interpreted as the regular expression. Therefore, if you were to expand out your search, it'd be:

print "ok\n" if $line ~~ /\/(\w+)\//;

Since your string doesn't start or end with slashes (or have any substrings that do), then the match fails, and you don't print ok.