Implement Component.__nonzero__ proper about circuits

[prologic]

Where if any of is this used and relied upon internally?
On May 13, 2015 4:38 PM, "spaceone" [email protected] wrote:

BaseComponent/Manager implements bool/nonzero which returns True if
there are pending events.
As it is a API to inherit from BaseComponent this is error prone.
I needed a lot time to debug the lines:

if arg:
foo()

which failed but worked finally with if arg is not None: (where arg is a
component, e.g. event.value.manager).

We should not overwrite pythons expected default behavior in the API and
instead hide internals like those.

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#51.

[spaceone]

At least in circuits/tests/core/test_core.py

[prologic]

Seems we removed this already

[spaceone]

hmm? Nothing is done here, yet.
bool/nonzero is still implemented

And the mentioned test case also still contains:
27 while app:
28 app.flush()

[prologic]

Show me? I grepped the codebase and could not find anything that implements this!

[spaceone]

circuits/circuits/core/manager.py

 230     def __len__(self):
 231         """x.__len__() <==> len(x)
 232 
 233         Returns the number of events in the Event Queue.
 234         """
 235 
 236         return len(self._queue)

[prologic]

Ahh yes but this doesn't implement __nonzero__. This gives you the queue length (no. of events in the queue) of a component (usually you want len(self.root))

[prologic]

You should still be able to implement your own __nonzero__ however in a component subclass.

[spaceone]

>>> class Foo(object):                                                                                                                                                                                                                                                           
...     def __len__(self):                                                                                                                                                                                                                                                       
...         return 0                                                                                                                                                                                                                                                             
... 
>>> 
>>> 
>>> f = Foo()
>>> bool(f)
False

[prologic]

So I'm proposing the following new public API(s):

• .empty
• .qsize

both properties.

Okay with this?

[spaceone]

uhm, no? I would leave __len__ as it is. But i would implement __bool__ and __nonzero__ to return True.

[prologic]

Oh man! Is that what you meant all along? sigh We need to improve are communications! I was totally lost as to what you were proposing :)

Let's try this again!

git checkout -- .
``

LOL

[prologic]

All this work I did for nothing and all the tests passing too :) Haha :)

[spaceone]

I'm really sorry :D You can use sed now to replace it: s/app.empty/len(app)/g.
Using properties here would be a disadvantage as they slow down the whole thing.