Re: What is the most efficient perl switch/case statement?

This doesn't answer your question, but i'd rather use a dispatch table (a lookup hash) instead of Switch ... but i rarely care about premature optimization. In your case, you are also checking regexes, so i would probably use Tie::Hash::Regex like so:

use strict;
use warnings;
use Tie::Hash::Regex;

tie my %hash, 'Tie::Hash::Regex';

%hash = (
   'foo.txt'  => 1,
   'bar.html' => 2,
   '..'       => undef,
   '.'        => undef,
   DEFAULT    => undef,
);

my $arg = shift || 'DEFAULT';
my $candidate = $hash{$arg};

die "invalid arg\n" unless $candidate;
print "$candidate\n";
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Since most of my work is Web based, i care more about maintainability and readability than efficiency .. but i do care about efficiency when it really matters.

UPDATE:
I forgot to mention CGI::Application which uses a dispatch table to control which runmode your CGI is in. If you haven't seen it yet, you really should RTFM on CGI::App ...

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

Comment on Re: What is the most efficient perl switch/case statement? Download Code

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Re: Re: What is the most efficient perl switch/case statement? by synistar (Pilgrim) on Nov 21, 2003 at 15:24 UTC
Actually, I do use CGI::Application. And I have used hashes as dispatch tables before (actually reinvented that wheel myself after dipping my toe in some assembly code). I usually use switch type statements for combining regex tests and other kinds of comparisons/tests (like in the example). I was not aware of Tie::Hash::Regex however. That is something I will rtfm on. CPAN is so massive I find it hard to keep up with it all (and that is a good thing). UPDATE:Tie::RegexpHash also seems like a pertinent module to check out. It allows one to use regexes as hash keys.	[reply]

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Re: Re: What is the most efficient perl switch/case statement?
by synistar (Pilgrim) on Nov 21, 2003 at 15:24 UTC

Actually, I do use CGI::Application. And I have used hashes as dispatch tables before (actually reinvented that wheel myself after dipping my toe in some assembly code). I usually use switch type statements for combining regex tests and other kinds of comparisons/tests (like in the example). I was not aware of Tie::Hash::Regex however. That is something I will rtfm on. CPAN is so massive I find it hard to keep up with it all (and that is a good thing).

UPDATE:Tie::RegexpHash also seems like a pertinent module to check out. It allows one to use regexes as hash keys.

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