Joe Strout wrote: > On Nov 14, 2008, at 2:07 PM, Paul McGuire wrote: > >> Or to be even more thorough: >> def sub(x: must have getitem, y: must have strip and strip must be >> callable, and y.strip must return something that has replace and >> replace must be callable) >> >> So even this simple example gets nasty in a hurry, let alone the OP's >> case where he stuffs y into a list in order to access it much later, >> in a completely different chunk of code, only to find out that y >> doesn't support the complete string interface as he expected. > > Very true. That's why I think it's not worth trying to be too pure > about it. Most of the time, if a method wants a Duck, you're going to > just give it a Duck. > > However, I would like to also handle the occasional case where I can't > give it a Duck, but I can give it something that is a drop-in substitute > for a Duck (really, truly, I promise, and if it blows up I'll take > responsibility for it). > [...]
I suspect this reduces our difference to a disagreement about the meaning of the word "occasional" ... regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
