On Mon, Jun 8, 2009 at 6:39 AM, Dag Sverre
Seljebotn<[email protected]> wrote:
> Dag Sverre Seljebotn wrote:
>> A decision is needed here within a few weeks; it would be great if any
>> core developers who don't care could respond to vote 0.
>
> *bump*
>
> Unless I hear something, I'm going to assume that people trust my
> opinion here and start implementing the solution below (it's kind of a
> blocker for Kurt's GSoC). Speak now or forever hold your peace...
>
> Dag Sverre
>

Perhaps you do not remember, but I've expressed my +1 for templates using  []

I'll just point that I like "MyType[int,float]" more than
"MyType[int][float]" ...

>
>
>>
>> The decision was made to use [] for templates. To reiterate the main
>> arguments:
>>
>>   - It leaves the way open for exporting pre-instantiated templates to
>> Python in a /very/ natural fashion.
>>
>>   - Templates are a bit like a collection of types anyway.
>>
>>
>> However this creates some syntax issues:
>>
>> A) Currently
>>
>>    cdef object[int] arr = ...
>>
>> can be used for PEP 3118 access on a generic object. While not a
>> technical problem (object will never become a template), it looks a bit
>> odd when introducing with a template feature.
>>
>> B) How would a templated buffer type look like? MyType[int][float]?
>>
>> Proposal:
>>
>> The object[int] syntax is removed (are anyone using it?). This is
>> basically done by making any cdef class with the
>> __cythonbufferdefaults__ magic attribute become a "buffer template".
>> Such cdef classes cannot be templates. Any other class cannot be used as
>> a buffer-supporting object.
>>
>> This removes functionality (much numeric code could care less about
>> whether the underlying object is an ndarray). As a substitute, the main
>> idea in http://wiki.cython.org/enhancements/buffersyntax is accepted,
>> which is to use
>>
>> cdef int[:] arr = ...
>>
>> for generic access, without any object access (this means that for now
>> only indexing and getting the shape is allowed at all.)
>>
>> I've been wondering a lot about whether this is the right way, and it
>> still seems so, even if it means that there will be (and likely continue
>> to be) two different ways of accessing a buffer; one through an explicit
>> "buffer type" and one through an "automatic template".
>>
>
>
> --
> Dag Sverre
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>



-- 
Lisandro Dalcín
---------------
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
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