[Python-Dev] PEP 3003 - Python Language Moratorium

[Dino Viehland]

Stefan wrote:
> It /does/ make some static assumptions in that it considers builtins
> true
> builtins. However, it does not prevent you from replacing them in your
> code, as long as you do it inside the module. Certainly a restriction
> compared to Python, where you can import a module into a changed dict
> environment that redefines 'object', but not a major restriction IMO,
> and certainly not one that impacts much code.

To me this is a deal breaker which prevents Cython from being a Python
implementation.  From a talk given by Colin Winter at the LLVM dev meeting
(http://llvm.org/devmtg/2009-10/) it seems like Unladen Swallow wanted to
do something like this as well and Guido said no.  In this case the breaking
change is so subtle that I'd personally hate to run into something like 
this porting code to Cython and having to figure out why it's not working.

More generally if all the implementations pick and choose what features of
Python we want to ignore for performance reasons then we'll just end up 
w/ a bunch of incompatible things that look very similar.