From: Xeno Campanoli <xeno@...>
Date: 2005-10-24T13:43:18+09:00
Subject: Re: Bit of fun II



Lyndon Samson wrote:

>More idle coding :-) A simple Compiler/Assembler/VM for a ( very basic
>) RPN (dc) style language. I suspect its quite amenable to golfing,
>but at a cost to readability.
>
>def compile(pgm)
>  outs = []
>
>  lines = pgm.split("\n")
>  
>
Why not save a step and just do:

pgm.each_line { |line|...?

>  lines.each { |line|
>    tokens = line.strip.chomp.split(" ")
>    pos = 0
>    while true
>      case tokens[pos]
>        when '+'
>          outs << "pop 1"
>          outs << "pop 2"
>          outs << "addr 1,2"
>          outs << "push 1"
>        when 'p'
>          outs << "pop 1"
>          outs << "print 1"
>        when '',nil
>        else
>          outs << "loadr 1,#{tokens[pos]}"
>          outs << "push 1"
>      end
>
>      pos = pos + 1
>      break if pos > tokens.length
>    end
>  }
>
>  return outs.join("\n")
>end
>
>def assemble(pgm)
>  mem = []
>  pc = 0
>
>  lines = pgm.split("\n")
># Same comment as above...?
>  lines.each { |line|
>    tokens = line.strip.split(/ |,/)
>    case tokens[0]
>      when 'loadr'
>        mem[pc]=1
>        mem[pc+1]=tokens[1].to_i
>        mem[pc+2]=tokens[2].to_i
>        pc = pc+3
>      when 'addr'
>        mem[pc]=2
>        mem[pc+1]=tokens[1].to_i
>        mem[pc+2]=tokens[2].to_i
>        pc = pc+3
>      when 'print'
>        mem[pc]=3
>        mem[pc+1]=tokens[1].to_i
>        pc = pc+2
>      when 'push'
>        mem[pc]=4
>        mem[pc+1]=tokens[1].to_i
>        pc = pc+2
>      when 'pop'
>        mem[pc]=5
>        mem[pc+1]=tokens[1].to_i
>        pc = pc+2
>    end
>
>  }
>
>  mem.push(0)
>
>  return mem
>end
>
>def execute(mem)
>  pc = 0
>  regs=[]
>  stack=[]
>
>  while true
>    #puts "> PC:#{pc} CODE:#{mem[pc]} STACK:#{stack.join(',')}"
>
>    case mem[pc]
>      when 0
>        break
>      when 1
>        regs[mem[pc+1]] = mem[pc+2]
>        pc=pc+3
>      when 2
>        regs[mem[pc+1]] = regs[mem[pc+1]] + regs[mem[pc+2]]
>        pc=pc+3
>      when 3
>        puts "#{regs[mem[pc+1]]}"
>        pc=pc+2
>      when 4  #push
>        stack.push(regs[mem[pc+1]])
>        pc=pc+2
>      when 5  #pop
>        regs[mem[pc+1]] = stack.pop()
>        pc=pc+2
>    end
>  end
>
>end
>
>aapgm = compile("12 10 + 14 + p")
>code = assemble(aapgm)
>
>execute(code)
>
>
>--
>Into RFID? www.rfidnewsupdate.com Simple, fast, news.
>
>
>
>
>  
>

-- 
Xeno Campanoli:  http://www.eskimo.com/~xeno
The real disaster is ANY TIME WE GET A BUSH FOR PRESIDENT!