Set variables from m//

ebarrere has asked for the wisdom of the Perl Monks concerning the following question:

Hello oh wise monks; please pardon my n00biness. :)

I'd like to set some variables to the results of regex backreferences in an m// statement. An example is worth a thousand words:

m/^(\s)?exten => (35\d\d)[^;]+;(.*)/ &&my ($extension,$name) = ($2,$3)
[download]

like so does not work ("Can't modify logical and (&&) in scalar assignment at...").

Oddly, this works:

m/<same regex>/ && print ($2,$3);
[download]

Hopefully what I'm trying to do is clear from my snippets! Is there a way to do it? Thanks in advance!

Comment on Set variables from m// Select or Download Code

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Re: Set variables from m// by ikegami (Patriarch) on Jun 24, 2009 at 01:35 UTC
It's a precedence problem `m/^(\s)?exten => (35\d\d)[^;]+;(.)/ && ( my ($extension,$name) = ($2, +$3) );` [download] but conditionally executing a `my` is not allowed and makes no sense. You want `my (undef, $extension, $name) = m/^(\s)?exten => (35\d\d)[^;]+;(.)/;` [download] Better yet, get rid of the needless capture `my ($extension, $name) = m/^(?:\s)?exten => (35\d\d)[^;]+;(.)/;` [download] Why are parens being used at all? `my ($extension, $name) = m/^\s?exten => (35\d\d)[^;]+;(.)/;` [download]	[reply] [d/l] [select]
Re^2: Set variables from m// by ebarrere (Initiate) on Jun 24, 2009 at 02:33 UTC
Ah, perfect! Won't the second example capture the wrong backreferences though? As for the parens, I guess you're right; that will just force it into an array context unnecessarily, no? Thanks!	[reply]
Re^3: Set variables from m// by ikegami (Patriarch) on Jun 24, 2009 at 02:50 UTC
Won't the second example capture the wrong backreferences though? I don't see any backreferences. I don't see a problem. The first capture will be assigned to undef (i.e. dropped), the second will be assigned to `$extension`, the third will be assigned to `$name`. As for the parens, I guess you're right; that will just force it into an array context unnecessarily, no? I meant the parens around `\s`. It was like doing `$z=($x)+($y);` instead of `$z=$x+$y;`	[reply] [d/l] [select]