1.5.2 and functools or similar

[castironpi at gmail.com]

On Mar 9, 4:26 pm, "Troels Thomsen" <nej tak ...> wrote:
> Hello,
>
> I am writing a simple delayed-call mechanism , that is causing a bit of
> headache. Works like this:
>
> myPrint(s)
>   print "..." + s
>
> myTimer.add(myPrint , "hello" , 15)
>
> This means that the myprint function is called in 15 seconds with the
> parameter "hello".
> The housekeeping of these timers is called by the main loop of the "os"
>
> This works well but i would like to be able to use it with any number of
> parameters
>
> Functools is not a part of the 1.5.2+ python that I am running on (embedded
> device),
> so i tried to pass the parameters as a tuple like this
>
> myTimer.add(myAdder , (3,6) , 15)
>
> and the housekeeping function would then call the function like this
>
> def updateTimers()
>   for timerItm in timerTable:
>   ...
>     ....
>       ....
>         timerItm.func(*timerItm.parameters)
>
> Works well on python 2.5 but not on 1.5.2 (?)
>
> Current solution is to have default parameters None for the add function
>
> def add( func , timeout , param1 = None , param2 = None)
>
> And the update function then checks if parameters is specified
>
> def updateTimers()
>   for timerItm in timerTable:
>   ...
>     ....
>       ....
>       # ugly part :
>       if timerItm.param1 is not None and timerItm.param2 is not None:
>         timerItm.func(timerItm.param1, timerItm.param2) # two parameters
>       elif ......
>         timerItm.func(timerItm.param1) # one parameter
>       else
>         timerItm.func() # no parameters
>
> This has the implication that I can not call a function with the parameter
> None if I wanted to.
> (not a huge problem)
>
> Right now it works quite well with up to two parameters, it covers 99% of
> usage. If I need to call a function with more parameters, i can always write
> a wrapper function for it. Wondering if anyone had some sugestions ?
>
> By the way, is it bad style to check for object identity instead of value
> "None".
> What aboutt integers ? if value is 0: ..
> I guess it is implementation specific / could change in future versions ?
>
> Thx,
> Troels

def g( arg1, arg2 ):
   print( arg1, arg2 )
   return arg1

def h( arg1 ):
   print( arg1 )
   return arg1

def caller( fun, *args, **kwargs ):
   return fun( *args, **kwargs )

print( caller( g, 'abc', 'def' ) )
print( caller( h, 'abc' ) )

'''
abc def
abc
abc
abc
'''