[Python-Dev] Re: Proper tail recursion (original) (raw)

Phillip J. Eby pje at telecommunity.com
Fri Jul 16 20:03:25 CEST 2004

At 10:45 AM 7/16/04 -0700, Josiah Carlson wrote:

IMO it shouldn't be only about tail-call optimizations. Andrew Koenig suggested that frames be allocated from the heap, which if it is possible (is there anything that gets executed directly by the processor so we have to worry about processors supporting NX?), seems to remove the C stack limit.

Frames are allocated on the heap. That's not the problem. The problem is that the interpreter has to use the C stack to call C functions, and Python objects are implemented using C functions. Therefore, invoking operations on Python objects uses the C stack, in the general case.

(Which is why some versions of Stackless made extensive modifications to the Python core, in order to maximize the number of specific cases where C function calls could be avoided.)

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