Verifiably better, validated Enum for Python

[Steve D'Aprano]

On Wed, 24 May 2017 01:47 pm, breamoreboy at gmail.com wrote:

> Well that's what is says here https://github.com/ofek/venum so it must be
> true.  Please move over Ethan, your time is up :-)

The page says:

    venum provides an Enum that is actually just a namedtuple, but 
    easier to create. This means an Enum can be created during 
    program execution and members are truly immutable (can't 
    dynamically add new ones). Also, this saves a bit of space 
    over the stdlib's Enum.


(1) Std lib enums are created during program execution too.

(2) Being namedtuples is a negative, not a positive.

(3) Members being immutable may, or may not, be a good thing, depending on
the application.

(4) If it is true that venum uses less space (memory? disk space?) than
enum, that would be a positive.


The example given is:

>>> from venum import Enum
>>> ContentTypes = Enum(
...     ('JSON', 'application/json; charset=utf-8'),
...     ('HTML', 'text/html; charset=utf-8'),
...     ('JS', 'text/javascript; charset=utf-8'),
...     ('XML', 'application/xml'),
...     ('TEXT', 'text/plain; charset=utf-8'),
...     ('JPEG', 'image/jpeg'),
...     ('PNG', 'image/png'),
...     ('YAML', 'application/x-yaml'),
...     name='ContentTypes'
... )


but I'm not convinced that's "verifiably better" than:

from enum import Enum
class ContentTypes(Enum):
    JSON = 'application/json; charset=utf-8'
    HTML = 'text/html; charset=utf-8'
    JS = 'text/javascript; charset=utf-8'
    XML = 'application/xml'
    TEXT = 'text/plain; charset=utf-8'
    JPEG = 'image/jpeg'
    PNG = 'image/png'
    YAML = 'application/x-yaml'



Although I wonder:

- maybe the enumeration (the class ContentTypes) could have a nicer repr
than 

<enum 'ContentTypes'>

- maybe you could add functionality to freeze the enumeration so that new
members cannot be added?


class ContentTypes(Enum, frozen=True)
class ContentTypes(FrozenEnum)



-- 
Steve
Emoji: a small, fuzzy, indistinct picture used to replace a clear and
perfectly comprehensible word.