Guido van Rossum wrote: > Most school I proponents (perhaps you're the only exception) have > claimed that optimization is desirable, but added that it would be > easy to add hash-based optimization. IMO it's not so easy in the light > of various failure modes of hash(). (A possible solution would be to > only use hashing if the expression's type is one of a small set of > trusted builtins, and not a subclass; we can trust int.__hash__, > str.__hash__ and a few others.)
that's the obvious approach for the optimize-under-the-hood school -- only optimize if you can do that cleanly (to enable optimization, all case values must be either literals or statics, have the same type, and belong to a set of trusted types). this gives a speedup in all main use cases, and clear semantics in all cases. another approach would be to treat switch/case and switch/case-static as slightly different constructs; if all cases are static, put the case values in a dictionary, and do the lookup as usual (propagating any errors). </F> _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
