[Python-ideas] Yet another alternative name for yield-from

[Guido van Rossum]

On Thu, Apr 2, 2009 at 12:35 PM, Bruce Frederiksen <dangyogi at gmail.com> wrote:
> Another strange one: 'close with X'.
>
> This hinges on the 'close' method returning X and also that this could be
> done syntactically *without* making 'close' a reserved word by relying on
> 'with' already being a reserved word with very limited usage in the grammar:
>
>   generator_return_stmt: NAME 'with' testlist
>
> And then verify later that NAME is 'close' (or raise SyntaxError).
>
> I'm not that familiar with Python's parser to know if it could handle this
> or not (LL vs. LR)...

The current parser generator cannot deal with this -- when it sees a
NAME at the start of the line it has to decide which non-terminal to
pick to parse the rest of the line. Besides (before you put effort
into trying to fix this or prove me wrong) this syntax looks too weird
-- we don't normally refer to leaving a stack frame as "closing"
anything. Close is a verb we apply to other things, e.g. files -- or
generators. But not the current frame or generator.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)