Function can be an instance of profunctor.
Sure, though I haven't updated it to use
promap instead of dimap here yet. https://github.com/flunc/optics/blob/master/src/Internal/Profunctor/Class/Profunctor.js#L9
It's a formalization of decorators, I suppose.
at least for the plain
Function instance
It might be possible to create a bifunctor instance for the native
Map too.
Do you care about
Promises at all?
You could probably form a bifunctor over that.
My answer is no (at least for now).
I'll define a Pair type in the test suite to give us a convenient type with which to test.
Just taking a look over the sanctuary-type-classes code now. It looks quite promising.
Okay. It's a modified version of @safareli's gist. It's possible I botched some refactoring. It's also possible the gist is a little off.
What's wrong with it, do you think?
Due to the
while (args.length > 0 && !args[0].done)
It does what I would have expected if it is modified to:
while (args.length > 0 && !args.every(prop('done')))
Or if you'd prefer to not
every over each iteration, it could be refactored to something like:function chainRec(f, x) {
var next = function(x) { return {value: x, done: false}; };
var done = function(x) { return {value: x, done: true}; };
var out = [];
var todo = [x];
while (todo.length > 0) {
var xs = f(next, done, todo.shift());
var partitioned = xs.reduce(function(acc, x) {
var bucket = x.done ? acc[1] : acc[0];
bucket.push(x.value);
return acc;
}, [[], []]);
todo.unshift.apply(todo, partitioned[0]);
out.push.apply(out, partitioned[1]);
}
return out;
}
For example, you can define functions like
forever which will repeatedly run the same action sequentially for any given ChainRec.const forever = m =>
chainRec((next, _, _) => m.map(_ => next(void 0)), void 0);