#!/usr/bin/ruby

def evaluate_line line, sub
  l = line.clone
  sub.each do |n, v|
    l.gsub!('$' + n.to_s, v.to_s)
    l.gsub!(/([0-9]+\+[0-9]+)/) { |m| eval m }
  end
  l
end

def evaluate_for block, cond
  ret = []
  eval cond[0]
  while eval cond[1]
    local = Hash.new
    local_variables.each do |n|
      next if ['local', 'ret', 'cond', 'block'].index n
      local[n] = eval n 
    end
    ret += [evaluate_line(block, $constants.merge(local))]
    eval cond[2]
  end
  ret
end

unless filename = ARGV.pop
  puts "Usage:"
  puts "./precompiler.rb [CONST1=VAL1 [CONST2=VAL2 [CONST3=VAL3...]]] filename"
end

$constants = Hash.new

ARGV.each do |l|
  c = l.split "="
  next unless c.length == 2
  $constants[c[0]] = c[1]
end

f = File.open filename
c = 0
while !f.eof?
  l = f.gets.chop
  l = evaluate_line l, $constants
  if l =~ /^\/\/ ?for\(([^;]*);([^;]*);([^;]*)\)$/
    cond = [$1, $2, $3]
    l = f.gets.chop
    unless l =~ /^\/\/ ?\{$/
      puts "Syntax error after \"for\" instruction"
      exit
    end
    block = ""
    while !f.eof?
      l=f.gets
      break if l =~ /^\/\/ ?\}/ 
      block += l
    end
    (evaluate_for block, cond).each { |l| puts l}
  else
    puts l
  end
end