On Tue, 01 May 2012 16:18:03 +0200, Kiuhnm wrote:
> "Most Pythonic" doesn't mean better, unfortunately.
Perhaps. But this example is not one of those cases.
> For instance, assume that you want to write a function that accepts a
> dictionary of callbacks:
> func(some_args, callbacks)
>
> Pythonic way
> ------------
>
> def when_odd(n):
> pass
[snip multiple function definitions]
> func(some_args, {'when_odd' : when_odd,
> 'when_prime' : when_prime,
> 'before_check' : before_check,
> 'after_check' : after_check})
> My way
> ------
>
> with func(some_args) << ':dict':
> with when_odd as 'n':
> pass
> with when_prime as 'n':
> pass
If you actually try that, you will see that it cannot work. You get:
SyntaxError: can't assign to literal
Have you actually tried to use these code blocks of yours? I asked you
for a *working* example earlier, and you replied with examples that
failed with multiple NameErrors and no hint as to how to fix them. And
now you give an example that fails with SyntaxError. I'm reluctantly
coming to the conclusion that these "code blocks" of yours simply do not
work.
> with before_check as '':
> pass
> with after_check as '':
> pass
You have a bug in one or more of those callbacks.
Of course you do -- all non-trivial software has bugs. The question is,
how are you going to find it? You can't unit-test the individual
callbacks, because they don't exist in a form that can be tested.
So in this case, even though Python is slightly more verbose, and forces
you to have the discipline of writing named functions ahead of time, this
is actually a *good* thing because it encourages you to test them.
If the callbacks are trivial functions, the Pythonic way is to use
lambdas:
func(some_args, {'when_odd': lambda n: n-1,
'when_prime': lambda n: n**2 - 1,
...})
although I would discourage that unless they are *really* trivial. But
for callbacks of any complexity, they will need to be tested, otherwise
how do you know they do what you want them to do?
Your code blocks make unit testing of the callbacks impossible, and for
that reason the Pythonic way is better.
--
Steven
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