[Python-Dev] Very Strange Argument Handling Behavior (original) (raw)

Hagen Fürstenau hagen at zhuliguan.net
Fri Apr 16 10:04:38 CEST 2010

This behavior seems pretty strange to me, indeed PyPy gives the TypeError for both attempts. I just wanted to confirm that it was in fact intentional.

Oleg already answered why f({1:3}) raises a TypeError. But your question seems to be rather why dict({1:3}) doesn't.

For functions implemented in Python, non-string arguments are always rejected, but C functions (like the dict constructor) don't have to reject them. I don't see any benefit in allowing them, but it's probably not worth breaking code by disallowing them either.

I couldn't find this documented. Perhaps we should just say "don't rely on being able to pass non-string keywords" somewhere?

More information about the Python-Dev mailing list