nodejs - simple calculator server

gistfile1.coffee

sys  = require 'sys'
http = require 'http'
host = "0.0.0.0"
port = 3000
http.createServer (request,response) ->
  [_, op, a, b] = request.url.split "/"
  a = parseInt a
  b = parseInt b
  result = {
    "add": (a, b) -> a + b
    "sub": (a, b) -> a - b
    "mul": (a, b) -> a * b
    "div": (a, b) -> a / b
  }[op]? a, b
  response.writeHead 200, 'Content-Type': 'text/html'
  response.end "<h2> #{result} </h2>"
.listen port, host
sys.puts "Server running at http://#{host}:#{port}"

is this code is write