I already implemented my application using asynchronous programming with
generators and yield. It is running well in Pyjd, but it dies in Pyjs. I
think that the implementation of generator (or yield) in Pyjs has a
problem. Pyjs throws an error right after g.send():
asyncEngine.py, line 82:
g_next=g.send(g_next)
GUI.py, line 200:
self.addOutput(text)
SCRIPT5007: Unable to get property '__object' of undefined or null
reference
It is not a problem of the line "self.addOutput(text)" because the error
doesn't disappear even if I delete (or change) the line, and it runs well
in Pyjd. Another problem of asynchronous programming is that it is too
difficult to debug code. I will keep trying to debug, but I don't think
that I can fix this bug in Pyjs. So, I have no choice but looking at
another method other than asynchronous programming now.
Thanks for letting me know about Metero and reactive programming. I will
try to find a way to bring this technique in Pyjs. However, I still think
that my blocking method is the simplest way though not perfect.
Thanks again.
On Sunday, December 1, 2013 9:42:30 AM UTC+9, Lex Berezhny wrote:
>
> I think your time would be much better spent just learning to use
> asynchronous programming.
>
> If you insist on thinking synchronously then I'd suggest you look at
> Meteor and their reactive programming model. That would be a more flexible
> approach to bring to Pyjs than your blocking method.
>
> - lex
>
>
> On Sat, Nov 30, 2013 at 7:34 PM, Clavier <[email protected] <javascript:>
> > wrote:
>
>> Hi,
>>
>> I found that Pyjs supported only async remote call (ex:
>> HTTPRequest.AsyncPost(), but not HTTPRequest.Post()). It makes source code
>> complicated when a series of remote calls are using preceding results.
>> Many applications use a function call returning a value, but an async call
>> forces to separate the function and the return value making code
>> complicated. This is an example using xmlrpclib in Python:
>>
>> import xmlrpclib
>> s = xmlrpclib.ServerProxy('http://localhost:8000')
>> v1=s.pow(2,3) # pow() is a remote function
>> v2=s.add(v1,3) # add() is a remote function
>> v3=s.div(v2,2) # div() is a remote function
>>
>> Corresponding code for Pyjs is a lot more complicated (sudo code):
>>
>> s = JSONProxy('http://localhost:8000')
>> class ServiceHandler:
>> def onRemoteResponse(self, response, sender):
>> if sender=='pow':
>> self.return_of_pow=response
>> s.add(self.return_of_pow, 3, self)
>> if sender=='add':
>> self.return_of_add=response
>> s.div(self.return_of_add, 2, self)
>> if sender=='div':
>> self.return_of_div=response
>> handler=ServiceHandler()
>> s.pow(2,3, handler)
>>
>> The return values from the server are not directly passed, but
>> asynchronously passed to the event handler. It is nature of asynchronous
>> programming making code complicated. It is possible to make code simpler
>> using 'yield' command and generators, and this is how I am writing code in
>> Pyjs now. But this asynchronous programming style has a problem making
>> debugging more difficult because stack contents cannot be shown properly.
>>
>> So, I want to use synchronous calls like xmlrpclib of Python. It can
>> cause GUI interface to get stuck sometimes, but it is ok in most of
>> applications. In order to implement it in Pyjs, inserting a code waiting
>> server response is enough, but the control should go to the Pyjs main loop
>> because Pyjs cannot updates server response while user code is running.
>> So, I needed a function to force Pyjs to update server response.
>>
>> HTTPRequest.asyncPost('http://localhost:8000', handler)
>> while handler.did_server_responded!=True: #waiting server
>> response
>> force_Pyjs_to_update_events()
>>
>> Is there such a function in Pyjs? If not, I'd like to try to make one.
>> Please let me know if you have an idea.
>>
>> --
>>
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