#!/usr/bin/perl -w
use strict;

my $type = 'hatter';
my $arg  = 'using eval';
my $proc = "do_$type";

eval "$proc( \$arg )";
die( "Eval errored: $@" ) if $@;

sub do_hatter
{
   my( $foo ) = @_;
   print "This can be done $foo.\n";
}