I suggest IRC for such questions Generally __extend__ extends an existing class (so just adds methods). __extend__(pairtype(...)) is an implementation of double-dispatch multimethods
On Fri, Apr 17, 2015 at 6:58 PM, VanL <van.lindb...@gmail.com> wrote: > I am having some trouble wrapping my head around it. Reading through > rpython/tools/pairtype.py, it looks like it could be one or more of a number > of things: > > - An implementation of javascript-style prototypes. (The similarity: you > don't subclass an object in js - you use the base object as a prototype and > extend it with new functionality) > > - A way to do specialization and automatic dispatching on types so that a+b > works (both "a" and "b" know what they are, and whether they are compatible > with each other in an __add__/__radd__ sense, and what type should be > returned as a result of that call) > > - Sort of a first draft of ABCs, allowing composition and type buildup > without explicit inheritance (roughly, __extend__ is similar to > ABC.register) > > - Other? > > Thanks, > Van > > > _______________________________________________ > pypy-dev mailing list > pypy-dev@python.org > https://mail.python.org/mailman/listinfo/pypy-dev > _______________________________________________ pypy-dev mailing list pypy-dev@python.org https://mail.python.org/mailman/listinfo/pypy-dev
