[Chandler-dev] a new kind of enumeration type

[Grant Baillie]

Perhaps I should've been more explicit :o). Instead of

     class TriageEnum(schema.Enumeration):
         values = {"now": 0, "later": 1, "done": -1}

I would rather just write:

     class TriageEnum(schema.Enumeration):
         values = "done", "now", "later"

to produce the same values TriageEnum.done, TriageEnum.now, etc. (The  
values would be auto-generated, but would sort the same as the dict  
example).

--Grant


On 30 Aug, 2006, at 14:38, Phillip J. Eby wrote:

> Because dictionaries aren't ordered.
>
> At 02:07 PM 8/30/2006 -0700, Grant Baillie wrote:
>> Hmm.... Why not just have the declaration order be the sort order?
>>
>> --Grant
>>
>> On 30 Aug, 2006, at 13:57, Andi Vajda wrote:
>>
>>>
>>> While implementating Chandler's dashboard Bryan found that he
>>> needed better control over the sorting of enumeration values.
>>>
>>> Currently, enumeration values are strings and are sorted as such.
>>> For example, if one defines an enumeration with the schema API as
>>> follows:
>>>
>>>    class TriageEnum(schema.Enumeration):
>>>        values = "now", "later", "done"
>>>
>>> The values of this enumeration will be sorted as:
>>>     "done" < "later" < "now"
>>>
>>>
>>> Enter a new type of enumeration, an enumeration of constants. Such
>>> constants have a name and a value and are sorted on their value
>>> first. Multiple constants in an enum may have the same value, their
>>> name is used next in sorting.
>>>
>>> By using a dict for the enumeration's values instead of a tuple,
>>> one can define such a constant enumeration with the schema API:
>>>
>>>     class TriageEnum(schema.Enumeration):
>>>         values = {"now": 0, "later": 1, "done": -1}
>>>
>>> Upon definition, the TriageEnum class gets assigned three
>>> attributes called 'now', 'later' and 'done' that contain such a
>>> constant:
>>>
>>>    TriageEnum.now -> TriageEnum.now
>>>    TriageEnum.now.value -> 0
>>>    TriageEnum.now.name -> 'now'
>>>
>>>    repr(TriageEnum.now) -> 'TriageEnum.now'
>>>    str(TriageEnum.name) -> 'now'
>>>
>>> These constants are sorted by their values:
>>>     TriageEnum.done < TriageEnum.now < TriageEnum.later
>>>
>>> Andi..
>
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