HL commute

gistfile1.js

var R = require('ramda'),
    _ = require('highland');

// Hack in partial Fantasy Land support.
var p = Object.getPrototypeOf(_());

p.reduce = function (f, m) {
    console.log('m', m._incoming);
    return _.reduce(m, f, this);
};

p.ap = function ap(ap) {
    var self = this;
    return ap.collect().flatMap(function (arr) {
        return self.flatMap(function (f) {
            return _(arr).map(f);
        });
    });
};

_.of = function (x) {
    return _([x]);
};

// I wonder why we don't expose _.toArray...
var toArray = R.curry(function toArray(f, xs) {
    return xs.toArray(f);
});

console.log(R.commute(R.of, [[1, 2], [3, 4], [5, 6]]));
// => [ [ 1, 3, 5 ],
//      [ 2, 3, 5 ],
//      [ 1, 4, 5 ],
//      [ 2, 4, 5 ],
//      [ 1, 3, 6 ],
//      [ 2, 3, 6 ],
//      [ 1, 4, 6 ],
//      [ 2, 4, 6 ] ]

R.commute(_.of, _([_([1, 2]), _([3, 4]), _([5, 6])]))
    .each(toArray(_.log));
// => [ [ 1, 3, 5 ],
//      [ 2, 3, 5 ],
//      [ 1, 4, 5 ],
//      [ 2, 4, 5 ],
//      [ 1, 3, 6 ],
//      [ 2, 3, 6 ],
//      [ 1, 4, 6 ],
//      [ 2, 4, 6 ] ]