[Python-Dev] Identifier API

[Victor Stinner]

Le jeudi 13 octobre 2011 03:34:00, Victor Stinner a écrit :
> > We would need a new format for Py_BuildValue, e.g. 'a' for ASCII string.
> > Later we can add new functions like _PyDict_GetASCII().
> 
> The main difference between my new "const ASCII" string idea and
> PyIdentifier is the lifetime of objects. Using "const ASCII" strings, the
> strings are destroyed quickly (to not waste memory), whereas PyIdentifiers
> are intern strings and so they are only destroyed at Python exit.
> 
> I don't know if "const ASCII" strings solve a real issue. I implemented my
> idea. I will do some benchmarks to check if it's useful or not :-)

Ok, I did some tests: it is slower with my PyConstASCIIObject. I don't 
understand why, but it means that the idea is not interesting because the code 
is not faster. It is also difficult to ensure that the string is "constant" 
(test the scope of the string).

At least, I found a nice GCC function: __builtin_constant_p(str) can be used 
to ensure that the string is constant (e.g. "abc" vs char*).

Victor