[Python-Dev] str vs. unicode (original) (raw)

Alex Martelli aleax at aleax.it
Wed Jan 19 12:22:44 CET 2005

On 2005 Jan 19, at 11:10, Bob Ippolito wrote:

Do you REALLY think this should be True?! isinstance(foo, unicode) and foo != unicode(foo)

Hmmmm -- why not? In the generic case, talking about some class B, it certainly violates no programming principle known to me that "isinstance(foo, B) and foo != B(foo)"; it seems a rather common case -- casting to the base class'' (in C++ terminology, I guess) slices off'' some parts of foo, and thus equality does not hold. If this is specifically a bad idea for the specific case where B is unicode, OK, that's surely possible, but if so it seems it should be possible to explain this in terms of particular properties of type unicode.

Alex

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