callbacks in python

[Alexandru Mosoi]

does anyone know a nice implementation of callbacks in python? i have
issues mixing named & unamed parameters. i want build a callback over
a function such that some parameters are passed when callback is
created and the rest are passed when the function is called.

example:
callback = Callback(function, x=1, y)
callback(z, t=4, u)

[Fredrik Lundh]

Alexandru Mosoi wrote:

does anyone know a nice implementation of callbacks in python? i have
issues mixing named & unamed parameters. i want build a callback over
a function such that some parameters are passed when callback is
created and the rest are passed when the function is called.

example:
callback = Callback(function, x=1, y)
callback(z, t=4, u)

your use of the word "callback" is a bit unusual, and your example isn't
valid Python code, but it looks as if functools.partial might be what
you need:

http://docs.python.org/lib/module-functools.html

</F>

[Larry Bates]

Alexandru Mosoi wrote:

does anyone know a nice implementation of callbacks in python? i have
issues mixing named & unamed parameters. i want build a callback over
a function such that some parameters are passed when callback is
created and the rest are passed when the function is called.

example:
callback = Callback(function, x=1, y)
callback(z, t=4, u)

First problem is that all unnamed arguments must come BEFORE named ones (Python
limitation). To do what you want define you callback as a class instead.

class Callback(object):
def __init__(x, y):
self.x = x
self.y = y

def __call__(z, t, u):
#
# Do what you want done at every callback
#
callback = Callback(x, y)

callback(z, t, u)

-Larry

[Bruno Desthuilliers]

Alexandru Mosoi a écrit :

does anyone know a nice implementation of callbacks in python? i have
issues mixing named & unamed parameters. i want build a callback over
a function such that some parameters are passed when callback is
created and the rest are passed when the function is called.

example:
callback = Callback(function, x=1, y)
callback(z, t=4, u)

from functools import partial

callback = partial(some_func, x=1, y)
callback(z, t=4, u)

[Bruno Desthuilliers]

Bruno Desthuilliers a écrit :

Alexandru Mosoi a écrit :

>does anyone know a nice implementation of callbacks in python? i have
issues mixing named & unamed parameters. i want build a callback over
a function such that some parameters are passed when callback is
created and the rest are passed when the function is called.

example:
callback = Callback(function, x=1, y)
callback(z, t=4, u)

from functools import partial

callback = partial(some_func, x=1, y)
callback(z, t=4, u)

Stupid copy-paste :(

callback = partial(some_func, y, x=1)
callback(z, u, t=4)

[Fredrik Lundh]

Bruno Desthuilliers wrote:

from functools import partial

callback = partial(some_func, x=1, y)
callback(z, t=4, u)

>>from functools import partial
callback = partial(some_func, x=1, y)

File "<stdin>", line 1
SyntaxError: non-keyword arg after keyword arg

[Bruno Desthuilliers]

Fredrik Lundh a écrit :

Bruno Desthuilliers wrote:

>from functools import partial

callback = partial(some_func, x=1, y)
callback(z, t=4, u)

>>from functools import partial
>>callback = partial(some_func, x=1, y)

File "<stdin>", line 1
SyntaxError: non-keyword arg after keyword arg

Yeps, I noticed this a couple seconds after posting. Brains needs more
coffe...