Regex Mystery

[roho]

Greetings monks,

It's late, I'm tired, and I must be missing the obvious. I need another pair of eyes to see what I've overlooked. The code sample below tests a file name against a regex containing the same file name. The first test uses forward slashes (and works as expected). The second test uses backslashes and does not work.

Please note: I have tried escaping the backslashes, but it still fails. I have tried running the regex through the "qr()" function, but it still fails. What am I missing here? TIA for any help you can provide.

#!/usr/bin/perl
use strict;
use warnings;

# WORKS
my $file  = 'C:/tmp';
my $regex = 'C:/tmp';
if ($file =~ m/$regex/i) {
    print "\nTest with forward slashes -- If stmt is true...\n";
}

# FAILS
$file  = 'C:\tmp';
$regex = 'C:\tmp';
if ($file =~ m/$regex/i) {
    print "\nTest with backslashes -- If stmt is true...\n";
}

[tybalt89]

if ($file =~ m/\Q$regex/i) {

because \t is a tab.

[roho]

Thanks tybalt89. I knew it must be something obvious. Time to rest now.

[harangzsolt33]

Wait, wouldn't this be more appropriate?:

      if ($file =~ m/\Q$regex\E/i) ...

[Anonymous Monk]

theyre exactly the same

[InfiniteSilence]

...
# FAILS
$file  = 'C:\tmp';
$regex = qr~C:\\tmp~;
if ($file =~ m/$regex/i) {
    print "\nTest with backslashes -- If stmt is true...\n";
}

Prints...

Test with forward slashes -- If stmt is true...

Test with backslashes -- If stmt is true...

FYI coding while tired is a recipe for adding errors to code that you will find hard to find later.

[choroba]

> FYI coding while tired is a recipe for adding errors to code that you will find hard to find later.

But sometimes, coding while tired delivers at least something before the deadline. Life is hard.

[LanX]

There are various benefits of coding before sleep
• you get started
• you keep your sleeping brain busy with non social stuff
• you may wake up with a solution
• you may not contribute to the gene pool of the human race

[roho]

Thanks InfiniteSilence. You're right, working when tired produces diminishing returns.

[cavac]

In my case, that would be negative returns.

When i'm tired, i'm basically more productive doing nothing than when i'm touching code.

Also, for a few hours after i'm forced by my body to take my pain meds for bad back (usually once a month on average). And being on the autistic spectrum, there are sometimes days my brain just refuses to do anything productive and i just can't concentrate on one singel thing for more than a minute or so.