As a little sidenote on using lambdas I've found that when executing a
procedure through a GUI using lambdas that includes undo-worthy Maya calls,
Maya is logging each call seperately in the undo array which can be a pain
if you are doing a lot of different things during that procedure.
With some help from Ofer I've found the only workaround is to use a callback
object somewhat similar to the one implimented into pymel, but executing
it's content through maya.mel.eval().
My callback object looks like this:
*class Callback(object):
_callData = None
@staticmethod
def _doCall():
(func, args, kwargs) = Callback._callData
Callback._callData = func(*args, **kwargs)
def __init__(self, func, *args, **kwargs):
self.func = func
self.args = args
self.kwargs = kwargs
def __call__(self, *args):
Callback._callData = (self.func, self.args, self.kwargs)
if __name__ != '__main__':
mm.eval('python("' + __name__ + '.Callback._doCall()")')
else:
mm.eval('python("Callback._doCall()")')
return Callback._callData
*
the if-else in __call__() could maybe be replaced by:
*mm.eval('python("import sys; sys.modules["%s"].Callback._doCall()")' %
__name__)
*
but I haven't tested yet, so I didn't wanna post it.
If you are not doing any undo-ish maya calls though, this issue isn't
visible.
On Fri, Jan 9, 2009 at 3:35 AM, John Creson <[email protected]> wrote:
> Also, you could put a query into the function you are calling that finds
> the list for itself without relying on the button click to pass in the list.
> The query in the function could look into a string variable on a node in
> the scene, or query an environment variable, or query a text field control
> on the gui window.
>
>
>
> On Thu, Jan 8, 2009 at 6:41 PM, Chris G <[email protected]> wrote:
>
>> Also you can use functools.partial for this :
>>
>> from functools import partial
>>
>> def someDef(theList, someParameter):
>> ...
>>
>> cmds.button(command=partial(someDef, someList, someParameter=2))
>>
>>
>>
>> On Thu, Jan 8, 2009 at 2:24 AM, Ofer Koren <[email protected]> wrote:
>>
>>> Another way, somewhat similar to lambdas but without those 'buggy'
>>> behaviours, is to use a 'callback' object:
>>> class Callback:
>>> def __init__(self,func,*args,**kwargs):
>>> self.func = func
>>> self.args = args
>>> self.kwargs = kwargs
>>> def __call__(self,*args, **kwargs):
>>> return self.func(*self.args, **self.kwargs)
>>>
>>>
>>> def someDef(theList, someParameter):
>>> ....
>>>
>>> cmds.button(command = Callback(someDef, someList, someParameter = 2))
>>>
>>>
>>>
>>> (FYI - Pymel has a more robust version of this object which supports
>>> Undo: from pymel import Callback)
>>>
>>>
>>> On Wed, Jan 7, 2009 at 7:44 PM, Matthew Chapman <[email protected]>wrote:
>>>
>>>> This is a common mistake, the way you have written this python
>>>> will call 'someDef(someList)' and pass its results to named argument
>>>> 'command'. There are a couple ways to get this to work the way you would
>>>> like. My personal choice is this
>>>>
>>>> # Define a function that can take any named or unnamed arguments
>>>> # the * tells python to put any unnamed arguments into a list
>>>> # the ** tell python to put any names arguments into a dictionary
>>>>
>>>> def someDef( *args, **kwargs ):
>>>> # call function or have inline code that creates someList
>>>> someList = getSomeList()
>>>> print someList
>>>>
>>>> def buildUI():
>>>> # <insert all stuff that defines window>
>>>>
>>>> # create button and pass the function it self to the argument
>>>> # command=someDef() # will pass the result where as
>>>> # command=someDef # passes the actual function to the argument
>>>>
>>>>> cmds.button(command=someDef)
>>>>
>>>>
>>>> If you really want to pass in data in the call as its being
>>>> defined you should use a lambda. A lambda is an unamed function. I have
>>>> heard of lambdas being buggy in certain instances because of how they are
>>>> defined and stored in memory in modules like pyqt. Here is how you could
>>>> write is.
>>>>
>>>> def buildUI():
>>>> # ' ' ' ' ' ' ' ' ' ' ' \/
>>>>
>>>>> cmds.button(command=lambda *args : someDef(someList ))
>>>>
>>>>
>>>> If you new the namespace of you function you could always pass it as a
>>>> string to 'command'.
>>>>
>>>> def buildUI():
>>>> # ' ' ' ' ' ' ' ' ' ' ' \/
>>>>
>>>>> cmds.button(command="myModule.someDef([%s] )" % str(someList))
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>>
>>>
>>> - Ofer
>>> www.mrbroken.com
>>>
>>>
>>>
>>
>>
>>
>> >>
>>
--
JAKOB WELNER
_____________
Animator | R&D
jakob.welner.dk
--
JAKOB WELNER
_____________
Animator | R&D
jakob.welner.dk
--~--~---------~--~----~------------~-------~--~----~
Yours,
Maya-Python Club Team.
-~----------~----~----~----~------~----~------~--~---
