[Python-Dev] Optimization of Python ASTs: How should we deal with constant values?

[Thomas Lee]

Nick Coghlan wrote:
> Steve Holden wrote:
>> While not strictly related to the global statement, perhaps Adam 
>> refers to the possibility of optimizing away code with an assignment 
>> which would make a name be recognized as local? If you're worried 
>> about "yield" disappearing you should also be worried about 
>> assignments disappearing, since that might cause names to be 
>> interpreted as globals.
>
> And once you start annotating functions as generators or not, and 
> variable names as locals or cell variables or globals, you're starting 
> to build up a substantial fraction of the information that is already 
> collected during the symtable construction pass.
>
> Perhaps the initial attempt at this should just focus on identifying 
> those operations which have the potential to alter the results of the 
> symtable construction, and leave those to the bytecode optimisation 
> step for the moment. Doing the symtable pass twice seems fairly 
> undesirable, even if it does let us trim some dead code out of the AST.
>
Sounds good. We can always come back to it.

Cheers,
T