I think I will do something like this. Maybe instead of converting the
class name to a keyword, I'll just make a separate protocol IComponent or
something, that has a component-type function that returns a constant
keyword determined by the macro at compile time...
On Wednesday, 18 May 2016 15:50:21 UTC-7, tbc++ wrote:
>
> Well, if you store it in metadata you'll have to look it up in the
> metadata which is a hashmap lookup. As a method on a class it's a method
> call that returns a constant.
>
> On Wed, May 18, 2016 at 3:12 PM, JvJ <kfjwh...@gmail.com <javascript:>>
> wrote:
>
>> Will it be much better than type metadata, though?
>>
>> On Wednesday, 18 May 2016 12:50:48 UTC-7, tbc++ wrote:
>>>
>>> Or define components to have a member called (name-as-kw [this])
>>> returning a keyword version of the name of the type.
>>>
>>> On Wed, May 18, 2016 at 1:31 PM, James Reeves <ja...@booleanknot.com>
>>> wrote:
>>>
>>>> Why not use the name of the class as the key?
>>>>
>>>> - James
>>>>
>>>> On 18 May 2016 at 20:02, JvJ <kfjwh...@gmail.com> wrote:
>>>>
>>>>> I'm creating an entity-component-system architecture. To use it, you
>>>>> define component types, and put a bunch of components in a map to make an
>>>>> entity.
>>>>>
>>>>> The rule for entities is that they can only have one component of any
>>>>> given type, so I figured I would use the class to index it. However,
>>>>> since
>>>>> this doesn't seem possible,
>>>>> I think I'll just make my own "defcomponent" macro which acts almost
>>>>> like defrecord, but makes sure that the constructor associates an
>>>>> appropriate keyword type tag
>>>>> in the metadata.
>>>>>
>>>>> Looking up the metadata is slightly slower than normal type
>>>>> reflection, but I doubt it will make much of a difference.
>>>>>
>>>>> On Wednesday, 18 May 2016 11:43:22 UTC-7, Jason Felice wrote:
>>>>>>
>>>>>> I don't think there's a general workaround, and I'm not sure I have
>>>>>> enough context to know what you are doing specifically.
>>>>>>
>>>>>> On Wed, May 18, 2016 at 2:28 PM, JvJ <kfjwh...@gmail.com> wrote:
>>>>>>
>>>>>>> I suspected as much. It would be possible to mitigate the problem
>>>>>>> by not using the repl, but I want the library I'm making to be built
>>>>>>> around
>>>>>>> a repl-oriented workflow (like every good clojure library should).
>>>>>>>
>>>>>>> Is there any way around this, or do I have to resort to :type
>>>>>>> metadata?
>>>>>>>
>>>>>>> On Wednesday, 18 May 2016 11:07:37 UTC-7, Jason Felice wrote:
>>>>>>>>
>>>>>>>> When you reload a namespace with a record, the class for that
>>>>>>>> record gets recreated. It will be functionally equivalent, but a
>>>>>>>> different
>>>>>>>> object. I'll bet that classes hash on identity. (Though if they
>>>>>>>> hashed on
>>>>>>>> name, you'd still have this problem.)
>>>>>>>>
>>>>>>>> On Wed, May 18, 2016 at 1:31 PM, JvJ <kfjwh...@gmail.com> wrote:
>>>>>>>>
>>>>>>>>> I'm encountering a very strange error in some tests.
>>>>>>>>>
>>>>>>>>> The details are a bit complex, but I'm using type-indexed maps.
>>>>>>>>>
>>>>>>>>> So, given an object o, the map would be {(type o) o}. When I try
>>>>>>>>> to lookup with the key (type o), I don't get the value, even though I
>>>>>>>>> can
>>>>>>>>> clearly see it in the map.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I have a map instance called new-still in my tests, and I can
>>>>>>>>> clearly see that this is its value
>>>>>>>>>
>>>>>>>>> {specs.core_test.Position {:x 0, :y 0}}
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> However, when I try to compare the first key to the Position class
>>>>>>>>> (which it should be), I get this:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Fail in run-systems-tst
>>>>>>>>> expected: (= (first (keys new-still)) Position)
>>>>>>>>> actual: (not (= specs.core_test.Position
>>>>>>>>> specs.core_test.Position))
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> How is it that the class specs.core_test.Position is not equal to
>>>>>>>>> itself??
>>>>>>>>> Is this a bug, or just some quirk of compilation?
>>>>>>>>>
>>>>>>>>> Thanks.
>>>>>>>>>
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>>>
>>>
>>>
>>> --
>>> “One of the main causes of the fall of the Roman Empire was that–lacking
>>> zero–they had no way to indicate successful termination of their C
>>> programs.”
>>> (Robert Firth)
>>>
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>
>
>
> --
> “One of the main causes of the fall of the Roman Empire was that–lacking
> zero–they had no way to indicate successful termination of their C
> programs.”
> (Robert Firth)
>
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