CoffeeScript: Returning from internal anonymous functions

returnx.coffee

# Allows return values to be returned from anonymous functions within other functions. The function that
# the value should be returned from should be decorated with the `catchx` function, and the value should
# be returned using the `returnx` function. This is done by throwing the return value using `returnx`,
# than catching it inside the decorator and `return`ing it.

# Was previously part of a specific solution for iterators at https://gist.github.com/1953057

catchx = returnx = null
do ->
  ReturnValue = (@val) ->
  returnx = (val) -> throw new ReturnValue val
  catchx = (func) -> ->
    try func.apply this, arguments
    catch e
      return e.val if e instanceof ReturnValue
      throw e


# Usage:

find = catchx (arr) ->
  arr.forEach (v) -> returnx v if v%5 is 0

alert find [3..7]