How to generate functions in a loop in coco?

Question

I would like to generate functions in a loop:

for own k, v in t
  ctor::[k] = ->
    v(...)
    @

However, coco seems to generate just one function and reuse it:

var k, v, __ref, __own = {}.hasOwnProperty;
for (k in __ref = t) if (__own.call(__ref, k)) {
  v = __ref[k];
  ctor.prototype[k] = __fn;
}
function __fn(){
  v.apply(this, arguments);
  return this;
}

How to change the coco script to make the output following:

var k, v, __ref, __own = {}.hasOwnProperty;
for (k in __ref = t) if (__own.call(__ref, k)) {
  v = __ref[k];
  ctor.prototype[k] = function() {
    v.apply(this, arguments);
    return this;
  }
}

CLARIFICATION: With coco I mean this language: http://satyr.github.com/coco/ (a coffeescript fork).

Is [this](http://coco.tomaszewskiweb.com/) the "coco" you're talking about? — Pointy, Apr 17 '12 at 13:04

score 2 · Accepted Answer · answered Apr 17 '12 at 14:14

It's a feature. Writing function directly within a loop should be almost always avoided. JSLint forbids it saying "Don't make functions within a loop."

Your code in particular has a scope bug (all v in the dynamically created methods will refer to the same value). You should use let binding there:

for own k, v in t
  let
    ctor::[k] = ->
      v ...
      this

which compiles to:

var k, v, __ref, __own = {}.hasOwnProperty;
for (k in __ref = t) if (__own.call(__ref, k)) {
  v = __ref[k];
  (__fn.call(this, k, v));
}
function __fn(k, v){
  ctor.prototype[k] = function(){
    v.apply(this, arguments);
    return this;
  };
}

How to generate functions in a loop in coco?

1 Answers1