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
> <javascript:>> wrote:
>
>> Why not use the name of the class as the key?
>>
>> - James
>>
>> On 18 May 2016 at 20:02, JvJ <kfjwh...@gmail.com <javascript:>> 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.
>>>>>>>
>>>>>>> --
>>>>>>> You received this message because you are subscribed to the Google
>>>>>>> Groups "Clojure" group.
>>>>>>> To post to this group, send email to clo...@googlegroups.com
>>>>>>> Note that posts from new members are moderated - please be patient
>>>>>>> with your first post.
>>>>>>> To unsubscribe from this group, send email to
>>>>>>> clojure+u...@googlegroups.com
>>>>>>> For more options, visit this group at
>>>>>>> http://groups.google.com/group/clojure?hl=en
>>>>>>> ---
>>>>>>> You received this message because you are subscribed to the Google
>>>>>>> Groups "Clojure" group.
>>>>>>> To unsubscribe from this group and stop receiving emails from it,
>>>>>>> send an email to clojure+u...@googlegroups.com.
>>>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>>>
>>>>>>
>>>>>> --
>>>>> You received this message because you are subscribed to the Google
>>>>> Groups "Clojure" group.
>>>>> To post to this group, send email to clo...@googlegroups.com
>>>>> Note that posts from new members are moderated - please be patient
>>>>> with your first post.
>>>>> To unsubscribe from this group, send email to
>>>>> clojure+u...@googlegroups.com
>>>>> For more options, visit this group at
>>>>> http://groups.google.com/group/clojure?hl=en
>>>>> ---
>>>>> You received this message because you are subscribed to the Google
>>>>> Groups "Clojure" group.
>>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>>> an email to clojure+u...@googlegroups.com.
>>>>> For more options, visit https://groups.google.com/d/optout.
>>>>>
>>>>
>>>> --
>>> You received this message because you are subscribed to the Google
>>> Groups "Clojure" group.
>>> To post to this group, send email to clo...@googlegroups.com
>>> <javascript:>
>>> Note that posts from new members are moderated - please be patient with
>>> your first post.
>>> To unsubscribe from this group, send email to
>>> clojure+u...@googlegroups.com <javascript:>
>>> For more options, visit this group at
>>> http://groups.google.com/group/clojure?hl=en
>>> ---
>>> You received this message because you are subscribed to the Google
>>> Groups "Clojure" group.
>>> To unsubscribe from this group and stop receiving emails from it, send
>>> an email to clojure+u...@googlegroups.com <javascript:>.
>>> For more options, visit https://groups.google.com/d/optout.
>>>
>>
>> --
>> You received this message because you are subscribed to the Google
>> Groups "Clojure" group.
>> To post to this group, send email to clo...@googlegroups.com
>> <javascript:>
>> Note that posts from new members are moderated - please be patient with
>> your first post.
>> To unsubscribe from this group, send email to
>> clojure+u...@googlegroups.com <javascript:>
>> For more options, visit this group at
>> http://groups.google.com/group/clojure?hl=en
>> ---
>> You received this message because you are subscribed to the Google Groups
>> "Clojure" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to clojure+u...@googlegroups.com <javascript:>.
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>
>
> --
> “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)
>
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
