1989lzhh schrieb am 07.11.2014 um 05:48:
>> 在 Nov 7, 2014，02:56，Robert Bradshaw 写道：
>> Here's some proposed function pointer syntaxes; which are the most
>> obvious to understand/read/remember? Can you figure them out?
>>
>> cdef float (*F)(float)
>> cdef float (*G)(float (*)(float), float, float)
>> cdef float ((*H)(char*))(float (*)(float), float, float)
>>
>> vs
>>
>> cdef float -> float F
>> cdef (float -> float, float, float) -> float G
>> cdef (char*) -> (float -> float, float, float) -> float H
>>
>> vs
>>
>> cdef lambda float: float F
>> cdef lambda (lambda float: float), float, float: float G
>> cdef lambda (char*): lambda: (lambda float: float), float, float: float H
>>
>>
>> If you want a hint, the last is something that returns numerical
>> integration algorithm given a string name. Yes, you could use
>> typedefs, but you shouldn't have to. especially for the first.
>>
> Here are numba kind function annotation, I guess it may fit in here.
> cdef float(float) F
> cdef float(float(float), float, float) G
> cdef float(float(float), float, float)(char*) H
> I personally feel this kind of annotation is more packed that using ->.
I find it clearer than any of the above. And it still allows the use of
named arguments, i.e. you could say
cdef char*(float x, int y) F = ...
F(y=1, x=2.0)
Drawback is that you have to parse up to the name in order to distinguish
it from
cdef char*(float x, int y):
...
Then there's also
cdef char*(float x, int y) nogil F
And we have to disallow
cdef char*(float x, int y) with gil F
It gets a bit less readable when you take a proper lower-case variable
name, e.g.
cdef char*(float x, int y) nogil get_gil
We could fix some of that by allowing
cdef nogil:
cdef char*(float x, int y) get_gil
But then, that's adding yet another special case.
Stefan
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