On 19 avr, 16:34, andrew cooke <[EMAIL PROTECTED]> wrote: > On Apr 18, 4:48 am, Bruno Desthuilliers <[EMAIL PROTECTED]> wrote: > > [...] > > > Practically, this means that (amongst other niceties) : > > - you can define functions outside classes and use them as instance or > > class methods > > - you can add/replaces methods dynamically on a per-class or > > per-instance basis > > - you can access the function object of a method and use it as a function > > - you can define your own callable types, that - if you implement the > > appropriate support for the descriptor protocol - will be usable as > > methods too > > ok, that's convincing (i had thought the majority of these were > already > possible, albeit with some kind of hard-coded "magic" behind the > scenes).
Yep, the whole point is that it's not that hard-coded anymore. Python exposes most of it's inner mechanisms, so that you can taylor quite a lot of things to your needs. This is quite useful for writing clean frameworks needing very few boilerplate in the user code. > [...] > > > > by referring to the titanic > > > i didn't mean that python was a disaster, rather that the "iceberg" is > > > still there (i am not 100% sure what the iceberg is, but it's > > > something > > > to do with making namespaces explicit in some places and not others). > > > I guess you're thinking of the self argument, declared in the function's > > signature but not "explicitly passed" when calling the method ? > > not really. more to do with when namespaces (i am not sure i have the > right term - the dictionary that provides the mapping from name to > object) > are explicit or implicit. for example, python has closures (implicit > lookup) and "self" (explicit lookup). > > but as i said, i don't have a clear argument - something just feels > "odd". > at the same time, i know that language design is a practical business > and so this is probably not important. The fact is that everything you do with closures can be done with objects. OTHO, there are quite a lot of cases where defining a specific class would be just way too heavy, and a closure is much more lightweight. So yes, it's a matter of "practicality beats purity". While trying to remain as clean as possible, Python is definitively a practical language. > finally, thank you for pointing me to sql alchemy (i think it was > you?). Seems so. > it really is excellent. Indeed !-) -- http://mail.python.org/mailman/listinfo/python-list
