Callable or not callable, that is the question!

Fri Jul 12 03:36:30 EDT 2013

Ulrich Eckhardt <ulrich.eckhardt at dominolaser.com> wrote:
> Am 11.07.2013 16:11, schrieb Peter Otten:
>> Ulrich Eckhardt wrote:
>>> Bug or feature?
>>>> No bug. Missing feature if you come up with a convincing use-case.
>> class Parser:
> def _handle_bool(input):
> # ...
> pass
>> types = {'bool': _handle_bool,
> 'boolean': _handle_bool,}
>> def parse(self, line):
> t,s,v = line.partition(':')
> handler = types[t]
> return handler(v)
>> I want a utility function that really behaves just like a function. I'd 
> prefer to nest it inside the class that uses it, to make the code easier 
> to understand. Since I don't want the implicit self-binding either, I 
> would use staticmethod to make this clear, too.

But the example you gave works just fine as written! You are only using 
your utility function as a function so there's no need for it to be a 
staticmethod or indeed any other sort of method.
To be a convincing use-case you would have to show a situation where 
something had to be both a static method and a utility method rather than 
just one or the other and also where you couldn't just have both.
If you can persuade me that you need _handle_bool as both a static method 
and a utility function, you probably also need to explain why you can't 
just use both:
class Parser:
 def _handle_bool(input): ...
 handle_bool = staticmethod(_handle_bool)
-- 
Duncan Booth http://kupuguy.blogspot.com