CoffeeScript Currying

blog_currying.md

This is a function that does some currying:

add = (a,b) ->
  if not b?
    return (c) ->
      c + a
  a + b

JavaScript provides the capability to reflect on the number of arguments:

add.length

and to determine how many arguments were provided:

add = (a,b) ->
  if arguments.length < add.length
    return (c) ->
      c + a
  a + b

so it seems like it should be possible to write a function that magically returns a function that requires the right number of arguments. So I could have a function:

f = (a,b,c,d,e,f) ->
  ..

if invoked with:

f(1,2)

it should return:

(c,d,e,f) ->

anyone know how to do that?

I use bind all the time but take car with two things...

• it changes the context, first argument is the new context.
• some browsers doesnt support it yet.

The second one is easy to fix, you have to add a chunk of code from the mdn:

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Function/bind