note grinder <blockquote><i> Can anyone help me find an efficient implementation.</i></blockquote> <p>If the cost of a subroutine call is cheaper than scanning the list (which I suspect is the case), then you can assemble all the target patterns into one, perform a single match, and then dispatch to the sub that gives you what you want to substitute:</p> <code> #! /usr/local/bin/perl -w use strict; use Regexp::Assemble; my $ra; my %dispatch = ( 'food' => sub { 'pizza' }, 'water' => sub { 'beer' }, 'like' => sub { 'enjoy' }, '(\d+)F' => sub { int(($ra->mvar(1) - 32 ) * 5/9 ) . 'C' }, ); $ra = Regexp::Assemble->new( track => 1 )->add( keys %dispatch ); while( <DATA> ) { while( $ra->match($_) ) { my $m = $ra->matched; s/$m/&{$dispatch{$m}}/e; } print; } __DATA__ I'd like a glass of water with my food, it's 92F in here! </code> <p>... produces...</p> <code> I'd enjoy a glass of beer with my pizza, it's 33C in here! </code> <p>Generating the dispatch table from a data file is left as an exercise to the reader (but a pretty fun one, I might say).</p> <div class="pmsig"><div class="pmsig-29008"> <p align="right"><font size="-2">- another intruder with the mooring in the heart of the Perl</font></p> </div></div> 429692 429692