Alex Martelli wrote: > Ilias Lazaridis <[EMAIL PROTECTED]> wrote: [...] - google stuff
>>http://lazaridis.com/case/lang/python.html#simple_variable_access >> >>this leads to a new limitation: >> >>"#LIMITATION: large amount of repetitive code" > > One normally does not define large numbers of identical accessors (there [...] - (extensive elaboration) possibly one can provide the code for something similar to the ruby attr_accessor: class Talker def sayHello puts "Hello world" end attr_accessor :name, :age end thus they can later be accessed this way john.age = 19 print john.age >>I meant: reproduce the definition of the class (but without reproducing >>the source-code of the class) >> >>I have removed the "without code" remark, which was missleading. > > Aha! I see now, and it does make more sense. Yes, using inspect you > could surely emit for example skeletons for the various methods, with > e.g. a 'pass' in lieu of their code. However, since instance attributes > are determined by code that gets executed (in __init__, and maybe in > __new__ and even elsewhere), it's not really practical to find out what > attributes an instance would have without in fact creating such an > instance and introspecting on it. Would such instantiation be OK here? If I understand you right, it would be ok. The requirements are given by the template: john.sayYourClassDefinition() "john" is instantiated, when asked for his class definition. > In some cases instantiating a class might have externally visible > effects, say opening a network connection, or a database, etc, so you > might well want to forbid that for purely introspective purposes. see above. >>yes, you are right. >> >>=> {New Requirement: ability to declare objects as mutable/immutable.} > > ... > >>I estimate that there is a "unfreeze" operation, too - which would lead >>to flexibity. > > Yes, but also mean that immutable objects are not really immutable, only > "immutable until further notice". For example, the immutability of [...] - (elaborations) I understand now. => {New Requirement: ability to declare objects as immmutable or mutable/immutable} >>>There's no need to define this 'meta' attribute anywhere, it just >>>springs into existence when you assign to it. >> >>? >> >>"assign to it" with: >> >>setattr(Talker, 'meta', "Class meta information") >> >>but _not_ with this: >> >>Talker.meta = "Class meta information" >> >>correct? > > Nope: both forms have IDENTICAL semantics. They both work in just the > SAME way. > > Try it out...! But this means that "assignment of metadata" works fine. >>>>class Talker(object): pass > > ... > >>>>Talker.meta = 'class metainfo' >>>>print Talker.meta > > class metainfo thus if I make a typo, I create a new attribute? . -- http://lazaridis.com -- http://mail.python.org/mailman/listinfo/python-list
