[Openmcl-devel] type specifier '(simple-vector n) in defmethod

[Tim McNerney]

Thanks for the support, Phoe.

 From the technological context of early CL history, I do sort-of "get" 
some of the thinking behind method dispatch limitations. (Too bad Gregor 
isn't here to speak for himself). At the time, Common Lisp proponents 
were deathly afraid of Lisp's reputation as a "slow language," so it is 
unclear that CL being originally designed in the /absence/ of CLOS is to 
blame. I suppose it is interesting that, at least in my circles, 
performance declarations never caught on (e.g. speed 3, safety 0). In my 
professional work, I have been known to seek out and destroy such 
monsters in every library we use.

--Tim

On 1/5/24 8:44 AM, Michał "phoe" Herda wrote:
>
> I'm not arguing that it shouldn't be in CL, I'm arguing that it's not 
> there because no one has done it. I guess you're free to extend CCL 
> with the functionality you're proposing, i.e. by introducing a new 
> method specializer in addition to the current class and EQL 
> specialization.
>
> Once a single working implementation is there, it's much easier to 
> convince other implementations to add it and end up turning it into a 
> de-facto standard (like with package-local nicknames).
>
> On 5.01.2024 14:41, Tim McNerney wrote:
>> To which, (at the risk of a civilized flame war), I say, "too bad."
>> IMHO, this was a short-sighted and poor design decision by the X3J13 
>> committee, /et al/.
>> The same debate came up within the greater Java community,
>>    and it is one place where Java and C# diverged.
>> Java's designers made similar choices to Common Lisp's:
>>    two kinds of datatypes, dispatchable objects and everything else.
>> C# is arguably "Java done right," where /everything/ is a 
>> dispatchable "object."
>>
>> There are clear benefits: it would also result in a cleaner, more 
>> appealing, more powerful language.
>> It's not too late to fix this flaw. What's the harm?
>> The "non-object" dispatch code would only be present in generic 
>> functions when necessary.
>>
>> --Tim
>>
>> On 1/2/24 6:17 AM, Michał "phoe" Herda wrote:
>>>
>>> No, standard CLOS dispatch happens only on classes.
>>>
>>> Have you tried https://github.com/digikar99/polymorphic-functions ?
>>>
>>> W dniu 2024-01-02 12:14, Taoufik Dachraoui napisał(a):
>>>
>>>> Hi
>>>> I am trying to use '(simple-vector n) as type specifier in 
>>>> defmethod but it is not possible, is there another way?
>>>>
>>>> (typep #(1 2 3 4) '(simple-vector 4))
>>>>
>>>> (defmethod mul ((n fixnum) (m1 (simple-vector n)) (m2 
>>>> (simple-vector n)))
>>>>   (let ((r (make-array (list n))))
>>>>     (dotimes (i n)
>>>>       (setf (svref r i) (* (svref m1 i) (svref m2 i))))
>>>>     r))
>>>> Kind regards
>>>> Taoufik Dachraoui
>>>
>>>
>>
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