[Python-Dev] constant/enum type in stdlib

[Michael Foord]

On 29/11/2010 00:48, Nick Coghlan wrote:
> On Mon, Nov 29, 2010 at 2:28 AM, Michael Foord
> <fuzzyman at voidspace.org.uk>  wrote:
>> For wrapping mutable types I'm tempted to say YAGNI. For the standard
>> library wrapping integers meets almost all our use-cases except for one
>> float. (At work we have a decimal constant as it happens.) Perhaps we could
>> require immutable types for groups but allow arbitrary values for individual
>> named values?
> Whereas my opinion is that "immutable vs mutable" is such a blurry
> distinction that we shouldn't try to make it at the lowest level.
> Would it be possible to name frozenset instances? Tuples? How about
> objects that are conceptually immutable, but don't close all the
> loopholes allowing you to mutate them? (e.g. Decimal, Fraction)
>
> Better to design a named value API that doesn't care about mutability,
> and then leave questions of reverse mappings from values back to names
> to the grouping API level. At that level, it would be trivial (and
> natural) to limit names to referencing Hashable values so that a
> reverse lookup table would be easy to implement. For standard library
> purposes, we could even reasonably provide an int-only grouping API,
> since the main use case is almost certainly to be in managing
> translation of OS-level integer constants to named values.

Sounds reasonable to me.

Michael

> Cheers,
> Nick.
>


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