mlhii,
Without putting in a bit of extra effort, string eval is the way to go. This is typically considered evil since it is like an open invitation to let ghosts into the machine - and not all of them are Casper. Here is a contrived way to do the same sort of thing safer, but it is more work:

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

my $eq_op = 'eq';
my $ne_op = 'ne';
my $foo = '1234';
my $bar = 'abcd';
my %compare = (
    eq => \&eq_compare,
    ne => \&ne_compare,
);
if ( $compare{ $eq_op }->($foo, $bar) ) {
     print "$foo and $bar are the same string\n";
}
if ( $compare{ $ne_op }->($foo, $bar) ) {
     print "$foo and $bar are not the same string\n";
}
sub eq_compare { return $_[0] eq $_[1] }
sub ne_compare { return $_[0] ne $_[1] }
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On advice from Corion in a /msg, I removed the ternary operator from the sub's returns as they were not needed. Of course, with subs this small you could make them anonymous as he has. Hmmph - my Casper story is funnier though