#!/usr/bin/ruby


# whitepsace-ruby
# Copyright (C) 2003 by Wayne E. Conrad
# 
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
# 
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
# 
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA

Opcodes = [
  ['  ', :push, :signed],
  [' \n ', :dup],
  [' \n\t', :swap],
  [' \n\n', :discard],
  ['\t   ', :add], 
  ['\t  \t', :sub],
  ['\t  \n', :mul],
  ['\t \t ', :div],
  ['\t \t\t', :mod],
  ['\t\t ', :store],
  ['\t\t\t', :retrieve],
  ['\n  ', :label, :unsigned],
  ['\n \t', :call, :unsigned],
  ['\n \n', :jump, :unsigned],
  ['\n\t ', :jz, :unsigned],
  ['\n\t\t', :jn, :unsigned],
  ['\n\t\n', :ret],
  ['\n\n\n', :exit],
  ['\t\n  ', :outchar],
  ['\t\n \t', :outnum],
  ['\t\n\t ', :readchar],
  ['\t\n\t\t', :readnum],
]

def error(message)
  $stderr.puts "Error: #{message}"
  exit 1
end

class Tokenizer

  attr_reader :tokens

  def initialize
    @tokens = []
    @program = $<.read.tr("^ \t\n", "")
    while @program != "" do
      @tokens << tokenize
    end
  end

  private

  def tokenize
    for ws, opcode, arg in Opcodes
      if @program =~ /\A#{ws}#{arg ? '([ \t]*)\n' : '()'}(.*)\z/m
        @program = $2
        case arg
        when :unsigned
          return [opcode, eval "0b#{$1.tr(" \t", "01")}"]
        when :signed
          value = eval "0b#{$1[1..-1].tr(" \t", "01")}"
          value *= -1 if ($1[0] == ?\t)
          return [opcode, value]
        else
          return [opcode]
        end
      end
    end
    error("Unknown command: #{@program.inspect}")
  end

end

class Disassembler

  def disassemble(tokens)
    for token in tokens
      if token[0] == :label
        puts "#{token[1]}:"
      else
        puts "%8s%-8s%s" % [nil, token[0], token[1]]
      end
    end
  end

end     

Disassembler.new.disassemble(Tokenizer.new.tokens) if $0 == __FILE__