[Python-Dev] pyc files, constant folding and borderline portability issues (original) (raw)
Terry Reedy tjreedy at udel.edu
Tue Apr 7 23:11:41 CEST 2009
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Alexandru Moșoi wrote:
From: "Cesare Di Mauro" <cesare.dimauro at a-tono.com> So if Python will generate
LOADCONST 1 LOADCONST 2 BINARYADD the constant folding code will simply replace them with a single LOADCONST 3 When working with such kind of optimizations, the temptation is to apply them at any situation possible. For example, in other languages this a = b * 2 * 3 will be replaced by a = b * 6 In Python I can't do that, because b can be an object which overloaded the * operator, so it must be called two times, one for 2 and one for 3. Not necessarily. For example C/C++ doesn't define the order of the operations inside an expression (and AFAIK neither Python)
Yes is does. Expression/Evaluation order "Python evaluates expressions from left to right."
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