AdventOfCode-2019/intcode_fibers.cr

def new_interpreter(f, p)
  prog = {} of Int64 => Int64
  p.each_with_index do |v, i|
    prog[i.to_i64] = v.to_i64
  end

  input = Channel(Int64).new
  output = Channel(Int64?).new
  spawn do
    op = ""
    pc = 0_i64
    base = 0_i64
    index = ->(i : Int32) {
      case op[-(3+i)]
      when '0'
        prog[pc+1+i]
      when '1'
        pc+1+i
      else
        prog[pc+1+i] + base
      end
    }
    get = ->(i : Int32) { prog[index.call(i)]? || 0_i64 }
    set = ->(i : Int32, v : Int64) { prog[index.call(i)] = v }
    loop do
      op = "0000" + prog[pc].to_s
      case op
      when .ends_with? "1"
        set.call(2, get.call(0) + get.call(1))
        pc += 4
      when .ends_with? "2"
        set.call(2, get.call(0) * get.call(1))
        pc += 4
      when .ends_with? "3"
        set.call(0, input.receive)
        pc += 2
      when .ends_with? "4"
        output.send(get.call(0))
        pc += 2
      when .ends_with? "5"
        pc = get.call(0) != 0 ? get.call(1) : pc + 3
      when .ends_with? "6"
        pc = get.call(0) == 0 ? get.call(1) : pc + 3
      when .ends_with? "7"
        set.call(2, get.call(0) < get.call(1) ? 1_i64 : 0_i64)
        pc += 4
      when .ends_with? "8"
        set.call(2, get.call(0) == get.call(1) ? 1_i64 : 0_i64)
        pc += 4
      when .ends_with? "99"
        input.receive
        output.send(nil)
        break
      when .ends_with? "9"
        base += get.call(0)
        pc += 2
      end
    end
  end
  {input, output}
end