#!/usr/bin/perl
use strict "vars";
use warnings;
system('clear');
our @tape;
our $pos = 15;
our @sa= qw(1>b 1>~);
our @sb= qw(0>c 9>b);
our @sc= qw(1<c 9<a);
our %instruction = (
    '1' =>  sub { $tape[$pos] = '1' },
    '0' =>  sub { $tape[$pos] = '0' },
    '9' =>  sub { $tape[$pos] = &randbit },
    '<' =>  sub { --$pos },
    '>' =>  sub { ++$pos },
    '~' =>  sub { print "END OF CALCULATION\n" ; exit 0 },
);
for ('a' .. 'z') { $instruction{$_} = sub { init("s".$_) } }
{ push @tape,'0' ; redo unless scalar @tape == 31 }
sub exec {
for ( unpack("(A1)*", $_[0]) ) {
        &{$instruction{$_}};
        select(undef, undef, undef, 0.025);
        print &print_tape . "\n";
} # the game.
}
sub init { ($_) = @_; ($tape[$pos] == 0) ? {&exec(${$_}[0])} : { &exec(${$_}[1]) } }
sub print_tape {
    my $t = join '', @tape;
    $t =~ s/(^.{$pos})(.)(.*$)/\033[0m${1}\033[1;37m${2}\033[0m${3}/;
    print $t;
    return "";
}
sub randbit {
    open(RAND,"/dev/urandom") or die;
    ord getc RAND > 127 ? 1 : 0;
    close(RAND)
}
init('sa');