#! perl -slw
use strict;
use Benchmark qw[ cmpthese ];

my %subst = ( '&' => 'amp', '>' => 'gt', '<' => 'lt' );

our $ysth = join('|', map quotemeta, sort { length($b) <=> length($a) || $b cmp $a } keys %subst);

our $N ||= 1e3;
our $data = join( '', map{ 'junk ' . (qw[ & < > ])[ rand 3 ]  } 1 .. $N );

cmpthese -3, {
    OP      => sub {
        $_ = $data;
        s{\&}{amp}g;
        s{\<}{lt}g;
        s{\>}{gt}g
    },
    tye     => sub {
        $_ = $data;
        s{([&<>])}{$subst{$1}}ge;
    },
    ysth    => sub {
        $_ = $data;
        s{($ysth)}{$subst{$1}}ge;
    },
    buk     => sub {
        $_ = $data . ' ';
        $_ = join 'amp', split '&';
        $_ = join 'lt', split '<';
        $_ = join 'gt', split '>';
        chop;
    },
};