#!/usr/bin/env perl

use strict;
use warnings;

use Benchmark 'cmpthese';

cmpthese(-30, {
    loop    => \&loop,
    assign  => \&assign,
});

my $BUFFER;

sub loop {
    $BUFFER .= '12345';
    say $BUFFER while parse(\$BUFFER);
}

sub assign {
    my $buffer = \($BUFFER .= '12345');
    1 while parse($buffer);
}

sub parse {
    my $buffer = shift;
    return substr ${$buffer}, 0, 1, '';
}