[Python-Dev] Hashable memoryviews (original) (raw)

Stefan Krah stefan at bytereef.org
Sun Nov 13 13:05:24 CET 2011

Nick Coghlan <ncoghlan at gmail.com> wrote:

> With slices or the new casts (See: http://bugs.python.org/issue5231, > implemented in http://hg.python.org/features/pep-3118#memoryview ), > it is possible to have different hashes for equal objects:

Note that Antoine isn't suggesting that the underlying hash be used as the memoryview's hash (that would be calculated according to the same rules as the equality comparison). Instead, the ability to hash the underlying object would just gate whether or not you could hash the memoryview at all.

I think they necessarily have to use the same hash, since:

exporter = m1 ==> hash(exporter) = hash(m1) m1 = m2 ==> hash(m1) = hash(m2)

Am I missing something?

Stefan Krah

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