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@DrBoolean
Last active January 12, 2016 21:38
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var Option = require('fantasy-options')
var Some = Option.Some;
var None = Option.None;
var Compose = function(x){
this.val = x;
}
Compose.prototype.map = function(f){
return new Compose(this.val.map(function(u){return u.map(f); }));
}
Compose.prototype.ap = function(c2){
var composed_f = this.val.map(function(u){ return function(y){ return u.ap(y); } });
return new Compose(composed_f.ap(c2.val));
}
Compose.of = function(x){ return new Compose(x) } // needs to do some crazy shit to find out inner functors
Some.prototype.traverse = function(f, of){
return f(this.x).map(function(y){ return Some(y); });
}
None.prototype.traverse = function(f, of){
return of(None)
}
Array.of = function(x){ return [x]; }
var _flatten = function(xs) { return xs.reduce(function(a,b){return a.concat(b);}, []) };
Array.prototype.ap = function(a2) {
return _flatten(this.map(function(f){
return a2.map(function(a){ return f(a); })
}));
}
Array.prototype.traverse = function(f, of) {
var cons_f = function(ys, x){
return f(x).map(function(x){ return function(y){ return y.concat(x); } }).ap(ys);
}
return this.reduce(cons_f, of([]));
}
// Naturality
var u = ["John", "Ham"]
//+ t :: Option a -> [a]
var t = function(opt){
return opt.cata({
Some: function(x) { return [x] },
None: function() { return [] }
});
}
var f = function(x){ return Some(x+"burgler"); }
var nat1 = t(u.traverse(f, Option.of))
var nat2 = u.traverse(function(y){ return t(f(y)) }, Array.of)
// nat1 == nat2
// Identity
var u = ["Tetris Boss"]
var id1 = u.traverse(Identity, Identity.of)
var id2 = Identity(u)
// id1 == id2
// Composition
var u = ["Jimmy"]
var f = function(x){ return Some(x + " eat") }
var g = function(x){ return Some(x + " hello world") }
var of = function(x){ return new Compose(Some(Some(x))); }
var comp1 = u.traverse(function(x){ return new Compose(f(x).map(g)); }, of)
var comp2 = new Compose(u.traverse(f, Option.of).map(function(v){ return v.traverse(g, Option.of) }));
//comp1 == comp2
@wayneseymour
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Possible to impl some (hopefully most || all) as free floating fn's?
What I mean to ask is, how to implement this functionality without using OOP in general, and the prototype in particular.

Thanks sir.

@DrBoolean
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@wayneseymour Oh goodness, I didn't see this until now. Yes, of course we can do so, but I like to use the prototypes since we're just implementing interfaces after all. There are some projects that pass a dictionary of definitions around and when a type implements an interface it just appends to that dictionary.

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