Brainfuck in Ruby (Yet another..)

#!/usr/bin/ruby
# Brainfuck Interpreter
# (C) Sebastian Kaspari 2009
# Usage: bf2 [FILE]

require 'rubygems'
require "highline/system_extensions"
include HighLine::SystemExtensions

code = ARGF.read # code
cp   = -1        # code pointer
p    = 0         # cell pointer
c    = [0]       # cells
s    = []        # bracket stack

until (cp+=1) == code.length
  case code[cp].chr
    when ">": (p += 1) && c[p].nil? && c[p] = 0
    when "<": p <= 1 ? p = 0 : p -= 1
    when "+": c[p] <= 254 ? c[p] += 1 : c[p] = 0
    when "-": c[p] >= 1 ? c[p] -= 1 : c[p] = 255
    when "[": s.push(cp + 1)
    when "]": c[p] == 0 ? s.pop : cp = (s.last - 1)
    when ".": print c[p].chr
    when ",": c[p] = get_character.to_i
  end
end

The ehanced version of this interpreter is now part of this "project": http://github.com/pocmo/Ruby-Brainfuck