On Thu, Apr 27, 2017 at 7:28 PM, Steven D'Aprano <st...@pearwood.info> wrote:
> > In my experience, what Python is lacking is a way to declare attributes > > outside of the constructor. Take a look at how it's done in C#, Swisft, > or > > Go. > > Since you apparently already know how they do it, how about telling us > (1) how they do it, and (2) *why* they do it? > They make attribure declarations at the class declaration scope be instance attributes. Python makes that kind of declaration class attributes (statics in some other languages). This is the spec for C#: https://goo.gl/FeBTuy The reason *why* they do it that way is because declaring instance fields/variables is much more frequent than declaring class ones. > > Object attributes outside of the constructor would solve things more > > relevant than the vertical space used when assigning constructor > parameters > > to attributes. > > Solve which things? > Instance attributes may be defined with or without default values without having to pass them as arguments to or mention them in a constructor. > > For example, multiple inheritance is well designed in > > Python, except that it often requires constructors with no parameters, > > which leads to objects with no default attributes. > > Can you elaborate? A class hierarchy in which there is multiple inheritance requires constructors with no arguments. This is typical: https://goo.gl/l54tx7 I don't know which would be the best syntax, but it would be convenient to be able to declare something like: class A: var a = 'a' And have "a" be an instance attribute. -- Juancarlo *Añez*
_______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
