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Comment by kailuowang | Hacker News Reader

To me the fundamental shortcoming for javascript is not its typelessness, it's the lack of language syntax support for asynchronous programming, which is the butter and bread for most javascript applications (server or client side).

I really hope I can do something like

for (

  ra <- asycn_opA(),

  rb <- async_opB(ra),

  _  <- asycn_opC(ra, rb)

).run()

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> it's the lack of language syntax support for asynchronous programming

    spawn(function*() {
        var ra = yield async_opA();
        var rb = yield async_opB(ra);
        yield async_opC(ra, rb);
    });

This works right now in Gecko: http://taskjs.org/. Something very close ought work in ES6/Harmony.

FWIW, there is talk of adding async/await like features (C#, Python) to TypeScript in a post 1.0 release.

So if you used Q or a similar library:

  Q.async(function*() {
    var ra = yield opA();
    var rb = yield opB(ra);
    yield opC(ra, rb);
  })().done();

Are you wishing for the other syntax or something that you can't achieve with generators/promises today?

Fortunately, with a bit of hacking, this style of syntax is possible without generators :) (I'm hoping to open source a library I wrote that works all the way back to IE6)

Here's your example rewritten in the 'monads' library (I probably need a better name):

monads(function() { var ra = opA.defer(); var rb = opB.defer(); var result = opC(ra(), rb()); });

Is that open source? I'd be interested in taking a look.

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