[Python-Dev] pyc files, constant folding and borderline portability issues (original) (raw)

skip at pobox.com skip at pobox.com
Mon Apr 6 18:57:44 CEST 2009 

Cesare> At this time with Python 2.6.1 we have these results:
Cesare> def f(): return 1 + 2 * 3 + 4j
...
Cesare> def f(): return ['a', ('b', 'c')] * (1 + 2 * 3)

Guido can certainly correct me if I'm wrong, but I believe the main point of his message was that you aren't going to encounter a lot of code in Python which is amenable to traditional constant folding. For the most part, they will be assigned to symbolic "constants", which, unlike C preprocessor macros aren't really constants at all. Consequently, the opportunity for constant folding is minimal and probably introduces more opportunities for bugs than performance improvements.

Skip

More information about the Python-Dev mailing list