Exceptions should be "exceptional". That is, you shouldn't expect them to happen during normal functioning of the program. So lets see what the overhead of providing (unused) exception handling is:

use strict;
use warnings;
use Benchmark 'cmpthese';

cmpthese(-1, {
    'eval'   => \&eval_code,
    'noeval' => \&no_eval_code,
});

sub eval_code {
    my $x = 0;
    for (reverse 0..9) {
        eval {
            some_more_code ($_);
        };
        if ($@) {
            error_sub();
        }
    }
}

sub no_eval_code {
    for (reverse 0..9) {
        if ($_==0) {
            error_sub();
        }
        else {
            some_more_code ($_);
        }
    }
}

sub some_more_code {
}

sub error_sub {
}

[download]

Prints:

           Rate   eval noeval
eval   185563/s     --    -7%
noeval 198639/s     7%     --

[download]

In words: the processing cost of an unexercised eval is essentially nothing.

DWIM is Perl's answer to Gödel

In reply to Re^2: Nested evals - are they evil? (sample benchmarks) by GrandFather
in thread Nested evals - are they evil? by cLive ;-)

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