Proof of concept of function-based promise (wrapper) implementation

gistfile1.js

// The (wrapper) implementation of function based promise

var Q = require('q');
var foo = {};

foo.sum = function(a, b) {

    function wrap_p(p) {
        function f() {
            var args = Array.prototype.slice.call(arguments);
            return wrap_p(p.then.apply(p, args));
        };

        f.then = p.then.bind(p);
        f.fail = p.fail.bind(p);
        f.done = p.done.bind(p);

        return f;
    }

    var p = Q.fcall(function() {
        console.log("foo.sum(" + a + ", " + b + ")");
        return a + b;
    });

    return wrap_p(p);
};

// The normal example

foo.sum(10, 10).then(function(x) {
    return x+10;
}).then(function(x) {
    return x*x;
}).then(function(x) {
    console.log('Result: ' + x);
}).fail(function(err) {
    console.error("Error: " + err);
}).done();

// The new style

foo.sum(10, 10)(function(x) {
    return x+10;
})(function(x) {
    return x*x;
})(function(x) {
    console.log('Result: ' + x);
}).fail(function(err) {
    console.error("Error: " + err);
}).done();


// The output:
// 
// $ node chain-test.js
// foo.sum(10, 10)
// foo.sum(10, 10)
// Result: 900
// Result: 900