[Python-Dev] C-level duck typing (original) (raw)

Dag Sverre Seljebotn d.s.seljebotn at astro.uio.no
Wed May 16 10:25:21 CEST 2012

On 05/16/2012 10:11 AM, Nick Coghlan wrote:

Use PyObjectHasAttr, just as people use hasattr() for ducktyping in Python.

In the Cython wrap-function-pointers case we really want performance comparable to C, so we couldn't do the whole thing.

But I guess we could intern some char* (somehow), pass that to tp_getattr, and then cast the returned PyObject* (which would not be a PyObject*) to a custom struct. As long as the interned strings can never be reached from Python that's almost safe. It's still slight abuse of tp_getattr.

As I said, if we didn't worry about performance we'd just retrieve capsules through attributes.

Dag

If you want something more structured, use Abstract Base Classes, that's what they're for. Cheers, Nick.

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