On Mon, Jun 1, 2009 at 3:55 PM, Alan Gauld <alan.ga...@btinternet.com>wrote:
>
> "W W" <sri...@gmail.com> wrote
>
>> class C:
>>> @constructor
>>> def LoadFromFile(fname, count): ...
>>> @constructor
>>> def Create(valueTuple):...
>>>
>>> Personally I prefer the Delphi style sincve it makes the constructor
>>> call explicit and adds to the documentation.
>>>
>>> Alan G
>>>
>>>
>> That does make it problematic... although I suppose checking the type
>> would
>> be a workaround - still, not simple or beautiful. Has this been introduced
>> as a PEP?
>>
>
> Type checking is the problem. Until Python can distinguish methods based
> on types (which introduces other issues) thisi is difficult with the
> C/Java style.
>
> We can fake the Delphi style by using a default constructor and then just
> calling the "constructors" after initialisation:
>
> class C:
> def __init__(): pass
> @constructor
> def LoadFromFile(fname, count): ...
> @constructor
> def Create(valueTuple):...
>
> c = C()
> c.LoadFromFile(fn, cnt)
>
> But its two lines not one... :-(
>
> And so far as I know it has not been PEPd although I'm sure it has
> been discussed.
I'm not sure how types are implemented in the underlying C, but it seems
that it should be a somewhat trivial addition. I mean, type checking is
already built-in to python, i.e. type('a') o/p: <type 'str'>, so just
building a handler specific to the __init__ method, or modifying it if it's
already unique, should be able to take care of it.
I guess one way you could try to parse it on your own is build a list of
types: f1 = [type(''), type(1), type(())], f2 = [type([]), type(1)]] and
compare the types of arguments provided from *args. I suppose really, one
could go so far as to build a dict of lists with the lengths:
spam = {1:[[type(''))],], 2:[[type([]), type(())], [type(1), type(1.0)]
then compare then lengths of args first.
That's a lot of work, though :P
-Wayne
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
