Spread-Repeat

spread.js

function numIter(max) {
    return function(signal) {
        if (signal) {
            var value = 0;
            return signal.takeWhile(function() { return value < max; })
                         .map(function() { console.log('iter('+max+')', value); return value++; })
                         
        } else {
            return Kefir.fromBinder(function(emitter) {
                var value = 0;
                while (value < max) emitter.emit(value++);
                emitter.end();
            });
        }
    }
}

function joinIters(arr) {
    var trg = [];
    var finished = [];
    var signal = signal || Kefir.emitter();    
    for (var i = 0; i < arr.length; i++) {
        trg.push(Kefir.repeat((function(i) {
            return function(cycle) {
                if (cycle === 1) {
                    console.log('finish', i); finished.push(i);
                }
                return arr[i]((cycle > 0) ? signal.toProperty(undefined) : signal);
            }
        })(i)));
    };
    var zipped = Kefir.zip(trg).takeWhile(function() {
        return (finished.length < arr.length);
    });
    return function(fn_res, fn_sig) {
        var stream_finished = false;
        zipped.onEnd(function() { stream_finished = true; });
        if (fn_res) zipped = fn_res(zipped);
        if (fn_sig) signal = fn_sig(signal);
        if (!zipped || !signal) return;
        while (!stream_finished) signal.emit();
    }
}

/* console.log('--------');

var e = Kefir.emitter();
Kefir.repeat(function(i) {
    if (i > 3) return;
    return numIter(5)(e);
}).log();

e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit();
e.emit(); */

console.log('--------');

/* var sig = Kefir.emitter();
sig.map(function() { return '!'; }).log('signal');
var stream_finished = false; 
joinIters([ numIter(4), numIter(17), numIter(3) ], sig).onEnd(function() { stream_finished = true; }).log('zipped');
while (!stream_finished) sig.emit(); */

joinIters([ numIter(4), numIter(17), numIter(3) ])(function(r) { r.log(); return r; });