On Feb 17, 10:35 pm, Nils Bruin <nbr...@sfu.ca> wrote: > Indeed, we have > > sage: MyHash.__dict__["__hash__"](h) > 0 > sage: print MyHash.__hash__(h) > 0 > sage: h.__hash__() > 0
Incidentally, this suggests that hash(a) does the following: 1] see if type(a).tp_hash is set. If so, use this 2] see if type(a) is eligible to inherit hash. If so, do "__hash__" lookup in the usual way. That suggests that classes that implement hash themselves can hash *much* faster than classes that inherit from it. I've scanned through PyType_Ready code but wasn't able to find any place where the tp_hash slot gets filled in from a superclass. This may apply for other slots too: manually filling in slots with routines that otherwise would be inherited could lead to significant speedups. Of course, you're breaking Python semantics. If subsequently, a super gets monkeypatched, your subclass won't pick up on the change. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
