[Python-ideas] Special keyword denoting an infinite loop

[Nick Coghlan]

On 29 June 2014 07:33, Andrew Barnert <abarnert at yahoo.com> wrote:
> Meanwhile, I think Nick's PEP 403, or something like it, is both more general and more Pythonic. Instead of trying to find a better way to embed function definitions into expressions, find a way to lift any subexpression out of an expression and define it (normally) after the current statement, and you solve the current problem for free, and a bunch of other problems too. (Although, unfortunately, none that really seem to demand solutions in practical code.)

On that last point, one of my goals at SciPy next month will be to
encourage folks in the scientific community that are keen to see
something resembling block support in Python to go hunting for
compelling *use cases*. The fatal barrier to proposals like PEP 403
and 3150 has long been that there are other options already available,
so the substantial additional complexity they introduce isn't
adequately justified. The two main stumbling blocks:

- generators-as-coroutines already offer a way of suspending execution
of a sequential operation, as embodied in asyncio.coroutine and
contexlib.contextmanager
- nested definitions of named functions are usually a readable
alternative in the cases lambdas can't handle

The reason I occasionally spend time on PEPs 403 and 3150 is because I
think we're missing a case where "one shot" functions could be handled
more gracefully - situations where we're defining a function solely
because we want to pass it to other code as an object at runtime, not
because we need to reference it at multiple places in the *source*
code. That's a pretty narrow niche, though - if you *do* need to
invoke the same code in multiple places, than a named function is
always going to be better, even if dedicated one-shot function support
is available.

Regards,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia