On 12/12/20 6:40 PM, Guido van Rossum wrote:
unlike Enum, duplicates are allowed
What does this even mean?
```
class K( NamedValue):
A = 1
A = 2
```
That's invalid. Duplicates allowed means:
> ```
> class K( NamedValue):
> A = 1
> B = 1
> ```
B is not an alias for A. Presumably one has the same number with different
meaning. If that were an Enum:
```
>>> K.B
K.A
unlike Enum, new values can be added after class definition
Sure, that points to maybe a subclass of Enum?
Not really -- adding a new member to an Enum is a royal pain.
unlike Enum, a NamedValue can always be used as-is, even if no data type has
been mixed in -- in other words, there is
no functional difference between MyIntConstants(int, NamedValue) and
MyConstants(NamedValue).
I'm not following this either. Can you give an example of something that doesn't work with Enum (and shouldn't work) but
should work with NamedValues?
Class MyEnum(Enum):
ONE = 1
TWO = 2
MyEnum.ONE + 3
# TypeError
Class MyValue(NamedValue):
ONE = 1
TWO = 2
MyValue.TWO + 3
5
Finally, why the plural in the name, where Enum and friends all have singular
names?
Because I constantly forget, and have to go back to remove the plural 's'.
By the way, the use of classes is not strictly required -- we could get everything except for immutable class access by
using mostly the same method as sre_parse._NamedIntConstant if we want a /slightly/ lighter weight structure -- which is
to say the NamedValueMeta is no where near as complicated as EnumMeta.
--
~Ethan~
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