On Fri, Sep 25, 2009 at 2:57 AM, Greg Ewing <greg.ewing@canterbury.ac.nz> wrote:
Guido van Rossum wrote:
So, you don't care abut the repetition of x in "x = f(x)" but you'd like to have a way to implicitly pass an argument giving the string name of the target variable, like "x = f('x')" ?
Yes. I'm defining a property, and the descriptor happens to need to know the name of the property being defined, but that's an implementation detail. The user shouldn't be required, or even allowed, to specify it as an independent parameter.
I'm not sure that it's common enough to warrant special
syntax;
Probably not very common in general, but I find myself doing this very intensively in some of my projects. I have two GUI libraries in which nearly every externally visible attribute is one of these properties.
A common pattern for this is to have a metaclass that walks over all the properties in the class (which are easily recognized using isinstance() or some other check) and calls them with an initialization function that passed in their name. -- --Guido van Rossum (home page: http://www.python.org/~guido/)