[Cython] CEP 507/513

[Stefan Behnel]

Hi,

Robert Bradshaw wrote:
> Reading CEP 513 again, I think the whole thing boils down to two things:
> 
> 1) Automatic cimport on import, under certain conditions (e.g. if a  
> corresponding .pxd file is found in the internal cython path)
> 2) Function overloading
> 
> The only reason Python didn't have (2) is because it had no way of  
> declaring types, and hence distinguishing between overloaded  
> functions (well, perhaps parameter count, but that's not very  
> compelling)). This will change in Python 3000 http://www.python.org/ 
> dev/peps/pep-3124/ , and I think we should backport that to Cython  
> (maybe not the whole PEP, but overloadable functions using @overload  
> or type signatures. In math.pxd one would declare sqrt for several  
> native types, and the object one would be the fallback. Def vs. cdef  
> could be interchangeable at this level.

The @overload decorator lives in a package called "overloading", according to
the examples.

Would it make sense to distinguish between

    from overloading import overload

and

    from overloading cimport overload

? Mind the "cimport" in the second example. Cython could handle cimported
decorators at compile time and move the evaluation of Python-imported
decorators to runtime, thus not even caring about where the decorator comes
from or what it does.

Should we use different semantics here or would this just complicate things?

Stefan