PEP 269

[Martin von Loewis]

> As stated in the PEP, one of the primary motiviations for the proposal is
> to allow grammar extensions to be prototyped in Python (esp. optional
> static typing.)  I would argue that making actual changes to CPython is
> much more expensive than writing a front end in Python.  By adding a pgen
> module to Python, I feel that we are not bloating Python so much as we are
> exposing funtionality already built into Python.

The potential problem is that this new module must then be supported
for a long time. People will propose extensions to it, which must be
evaluated, and every change must be reviewed carefully for
incompatibilities.

I'm not opposed to changes. However, I fail to see the value of
prototyping the grammar, since you'll need subsequent changes as well,
to the byte code generation, and perhaps evaluation. Also, I still
doubt anybody interested in changing the grammar couldn't easily
recompile Python.

Regards,
Martin