[Python-Dev] Re: anonymous blocks

[Steven Bethard]

On 4/27/05, Guido van Rossum <gvanrossum at gmail.com> wrote:
> I've written a PEP about this topic. It's PEP 340: Anonymous Block
> Statements (http://python.org/peps/pep-0340.html).

So block-statements would be very much like for-loops, except:

(1) iter() is not called on the expression
(2) the fact that break, continue, return or a raised Exception
occurred can all be intercepted by the block-iterator/generator,
though break, return and a raised Exception all look the same to the
block-iterator/generator (they are signaled with a StopIteration)
(3) the while loop can only be broken out of by next() raising a
StopIteration, so all well-behaved iterators will be exhausted when
the block-statement is exited

Hope I got that mostly right.

I know this is looking a little far ahead, but is the intention that
even in Python 3.0 for-loops and block-statements will still be
separate statements?  It seems like there's a pretty large section of
overlap.  Playing with for-loop semantics right now isn't possible due
to backwards compatibility, but when that limitation is removed in
Python 3.0, are we hoping that these two similar structures will be
expressed in a single statement?

STeVe
-- 
You can wordify anything if you just verb it.
        --- Bucky Katt, Get Fuzzy