[Python-ideas] a set of enum.Enum values rather than the construction of bit-sets as the "norm"?

MRAB python at mrabarnett.plus.com
Sun Dec 31 12:09:34 EST 2017

On 2017-12-31 08:13, Paddy3118 wrote:
> Hmm, yea I had not thought of how it would look - I had thought formost 
> of not needing to necessarily learn about bitsets.when learning about 
> passing a large number of optional flags to a function.
> Although the default could be None, interpreted as an empty set of zero 
> values.; a set of one or more enums does use more characters compared to 
> or-ing flags...
None is often used to represent a default, which might not be an empty set.

> On Sunday, 31 December 2017 05:34:23 UTC, Guido van Rossum wrote:
>     On Sat, Dec 30, 2017 at 8:50 PM, Franklin? Lee
>     <leewangzh... at gmail.com <javascript:>> wrote:
>         Paddy might want something like this:
>         - For existing APIs which take int or IntFlag flags, allow them to
>         also take a set (or perhaps any collection) of flags.
>         - In new APIs, take sets of Enum flags, and don't make them IntFlag.
>         - Documentation should show preference toward using sets of Enum
>         flags. Tutorials should pass sets.
>     I'm not keen on this recommendation. An argument that takes a
>     Set[Foo] would mean that in order to specify:
>     - no flags: you'd have to pass set() -- you can't use {} since
>     that's an empty dict, not an empty set
>     - one flag: you'd have to pass {Foo.BAR} rather than just Foo.BAR
>     - two flags: you'd have to pass {Foo.BAR, Foo.BAZ} rather than
>     Foo.BAR | Foo.BAZ
>     I think for each of these the proposal would be strictly worse than
>     the current convention.

More information about the Python-ideas mailing list