On Tue, May 16, 2017 at 5:04 PM, Guido van Rossum <gvanros...@gmail.com> wrote:
What features of attrs specifically solve your use cases? > (not Stephen) I hadn’t thought about this use case: In [1]: class C(): ...: x = 1 ...: ...: def __init__(self, x=None): ...: if x is not None: ...: self.x = x ...: ...: def __str__(self): ...: return 'C(%s)' % self.x ...: In [2]: c1 = C() ...: c2 = C(2) ...: In [3]: print(c1, c2) C(1) C(2) And I might use it here on. What I like about attrs is: - The class level declaration of instance attributes - That the reasonable *init*, *repr*, and *eq* are generated I don’t like the excessive wordiness in attrs, and I don’t need “the kitchen sink” be available to have instance attributes declared at the class level. A solution based on the typing module would be much better. Basically, Python is lacking a way to declare instance fields with default values away of the initializer. Several of the mainstream OO languages (Java, Swift, Go) provide for that. I haven’t thought much about this, except about if there’s indeed a need (and there is), but I can’t know if the solution if through decorators, or inheritance. -- 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/
