An Object's Type

[Diez B. Roggisch]

paul schrieb:
> Bruno Desthuilliers schrieb:
>> bg_ie at yahoo.com a écrit :
>>> Hi,
>>>
>>> Is it possible to find out if an object is of a certain type or of a
>>> type derived from this type?
>>>
>> You have the answer, thanks to Diez and Christian. Now unless you have 
>> a *very* compelling reason to check the type of an object, *just 
>> forget about it*. 9 times out of 10, this is fighting against the 
>> language's type system (hint: google for "duck typing").
> So I have to give up the concept that argument types are part of the 
> interface or signature? Honestly, I don't like that. Granted; not having 
> strict type checking makes for great flexibility but the price is you 
> either write typchecking code or let the error propagate into the 
> function or method. I hope type annotations in py3k will allow for 
> something like constraints in C# where you can tell the caller right 
> away she's doing something wrong.


This is a dead horse beaten into the ground, full way through to china. 
If you want typechecking - use a statically checked language. After all, 
if you like to constrain yourself to certain types - why not benefit 
from a compiler then?

I for once prefer to be able to pass object that behaves like e.g. a 
file - think StringIO - to something taking a file, instead of 
introducing a interface-maze like the java.io-hierarchy to capture each 
possible thinkable aspect of file IO in a separate interface - and then 
hoping that the third party library was careful enough to only require 
what is really needed.

Diez