Since they are samples of “async” builders. :)
We can use fs.mkdir, fs.readdir directly with another builder. Of couse the
Task object can be used as conitnuation callback (since everything is normal
JavaSript):
xxxAsync().on(“complete”, function () { console.log(this.result); }).start();
There’s no recompilation during the execution. There’s only one compilation and
eval for each single method definition.
Thanks
Jeffrey Zhao
From: Bruno Jouhier
Sent: Friday, August 24, 2012 1:48 AM
To: [email protected]
Subject: Re: [nodejs] Wind.js : An elegant approach to asynchronies JavaScript
Not sure I get it. From your samples
(https://github.com/JeffreyZhao/wind/blob/master/samples/async/node/copy-dir.js),
you need to wrap node's APIs:
fs.existsAsync = Binding.fromCallback(fs.exists);fs.mkdirAsync =
Binding.fromStandard(fs.mkdir);fs.readdirAsync =
Binding.fromStandard(fs.readdir);fs.statAsync =
Binding.fromStandard(fs.stat);fs.closeAsync =
Binding.fromStandard(fs.close);fs.openAsync =
Binding.fromStandard(fs.open);fs.readAsync =
Binding.fromStandard(fs.read);fs.writeAsync = Binding.fromStandard(fs.write);
With streamline you don't (except for exists which is a black swan :-( ). You
can directly call fs.mkdir, fs.readdir, etc.
Also, the xxxAsync functions that you write in Wind style return an instance of
Task and you run them with a start call, as xxxAsync(args).start(). Can you
call these functions from non-Wind code, with a continuation callback?
Something like xxxAsync(args).start(cb);
Also, you need an eval(Wind.compile('async', function(...) {...})) wrapper
around every async function that you define. This means that you are going to
compile and eval every time you create a new closure at runtime. You can
probably avoid the recompile (by caching it) but not the eval. Is this right?
Consider
function f1(x) {
return eval(Wind.compile('async', function(...) { var y = $await(f2());
return f3(x, y); });
}
Bruno
On Thursday, August 23, 2012 6:34:45 PM UTC+2, Jeffrey Zhao wrote:
You can also directly use Node.js style of API without binding if you need.
We just use Task model with “async” builder. As I said, Wind.js supports
different async model in parallel, you can choose whatever you prefer for each
single async method, like the simple and stand Node.js model, Promise/A model
or the Wind.js’s build-in Task model. The Task model just provides more
features for common used async patterns (e.g., task cancellation).
Thanks
Jeffrey Zhao
From: Bruno Jouhier
Sent: Friday, August 24, 2012 12:16 AM
To: [email protected]
Subject: Re: [nodejs] Wind.js : An elegant approach to asynchronies JavaScript
If your EntityStore interface uses standard callbacks:
EntityStore.prototype = {
get: function(id, cb) { ... },
save: function(entity, cb) { ... }
};
Streamline will let you use it "as is". You will be able to write your
wearEquipement function as:
function wearEquipment(characterId, equipmentId, _) {
// code in synchronised style
// for example:
var users = new EntityStore('users');
var user = users.get(userId, _);
});
From another streamline function you will call it as:
var result = wearEquipment(characterId, equipementId, _);
And people who don't use streamline will also be able to call it, just like
any other node.js async function (because the transformed function IS a
standard node.js async function!):
wearEquipment(characterId, equipmentId, function(err, result) {
// usual node.js code here
});
You do not have to introduce dual APIs with Async variants. You do not need
any eval(Wind.compile('async', function(...) {...})) wrapper in every async
function that you define, ... You get direct interoperability between
streamlined code and regular node.js code.
Bruno
On Thursday, August 23, 2012 5:31:15 PM UTC+2, Tony Huang wrote:
I'm transforming my game server into Wind.js style. And it's really
painless and smooth.
Wind.js has already provided the Wind.Async.Bindings.fromStandard and
Wind.Async.Bindings.fromCallback stubs to help you integrate existing codes.
For instance, I already have a EntityStore class which provides standard
style interface:
EntityStore.prototype = {
'get': function(cb) {
//...
},
'save': function(entity,cb) {
//...
}
};
In order to make it usable in Wind.js, I just added following codes at the
end of the module:
['get', 'save'].forEach(function(method) {
EntityStore.prototype[method + 'Async'] =
Wind.Async.Binding.fromStandard(EntityStore.prototype[method]);
});
As a result, I can access these methods in Wind.js easily in this way:
var users = new EntityStore('user');
var currentUser = $await(users.get(userId));
It's quite easy.
But in the other hand, Wind.js hasn't provide the reverse operation, so I
added 2 method to the library:
- Wind.Async.Binding.toStandard
- Wind.Async.Binding.toCallback
So I can replace my code method by method without any overhead:
My original code might be:
function wearEquipment(characterId, equipmentId, cb) {
//..... deep levels of callbacks
}
After refactoring, my code comes to:
var wearEquipmentAsync = eval(Wind.compile('async', function(characterId,
equipmentId) {
// code in synchronised style
});
var wearEquipment = Wind.Async.Binding.toStandard(wearEquipmentAsync);
Completely the same interface, the same function, but better-looking code.
On Thu, Aug 23, 2012 at 12:55 AM, Bruno Jouhier <[email protected]> wrote:
On Wednesday, August 22, 2012 12:55:41 PM UTC+2, Dominic wrote:
this is all very clever, but do code transformations really make
callbacks easier?
Take the streamline tutorial (doc:
https://github.com/Sage/streamlinejs/blob/master/tutorial/tutorial.md source:
https://github.com/Sage/streamlinejs/blob/master/tutorial/tuto7-parallel._js)
and write it with plain callbacks.
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