brainfuck.pl

brainfuck.pl

#!/usr/bin/env perl
use warnings;
use strict;
use feature qw/switch/;
open my $stream, $ARGV[0] or die "Can't open file: $!";
my $size = 3000;
my @cells = (1..$size);
my $mptr = 0;
my $cptr = 0;
my @loops;
for my $i (0..scalar(@cells)-1) {
    $cells[$i] = 0;
}
my $input = "";
while (<$stream>) {
    chomp;
    $input .= $_;
}
$input =~ s/[^\+\-\.\[\],<>]//g;
my $lleft = scalar(grep(/[\[]/, $input));
my $lright = scalar(grep(/[\]]/, $input));
die "Syntax error!" if $lleft != $lright;
while ($cptr < length($input)) {
    my $c = substr($input, $cptr, 1);
    $cptr++;
    given ($c) {
        when ("<") { if ($mptr == 0) {$mptr = $size;} else {$mptr--;} }
        when (">") { if ($mptr == $size) {$mptr = 0;} else {$mptr++;} }
        when ("+") { if ($cells[$mptr] == 255) {$cells[$mptr] = 0;} else {$cells[$mptr]++;} }
        when ("-") { if ($cells[$mptr] == 0) {$cells[$mptr] = 255;} else {$cells[$mptr]--;} }
        when (".") { print chr($cells[$mptr]); }
        when (",") { $cells[$mptr] = ord(substr(<STDIN>,0,1)); }
        when ("[") { push @loops, $cptr; }
        when ("]") { 
            if ($cells[$mptr] != 0) {
                $cptr = $loops[scalar(@loops)-1];
            } else {
                pop @loops;
            }
        }
    }
}