[Python-Dev] A minimal Python interpreter written in Python for experimenting with language changes
steve at pearwood.info
Mon Feb 5 22:40:13 EST 2018
On Sat, Feb 03, 2018 at 11:45:15AM +0100, asrp wrote:
> > Can you give an example of how you would do that? I don't mean the
> > mechanism used, I mean how would a developer implement a new syntactic
> > feature. Suppose I wanted to add a new clause to for...else, let's say:
> > for ... :
> > block
> > otherwise:
> > # runs only if the for-loop was empty
> > How would do I do that?
> If you tell me a bit more about the intended behaviour of "otherwise",
> I'd be happy to do an example with that clause.
Here's a faked session showing the sort of thing I am referring to.
(Note that this is just an example, not a proposal for a new language
for x in [1, 2, 3]:
prints 1, 2, 3.
for x in :
prints "nothing there". In other words, the otherwise block runs if, and
only if, the loop iterable is empty and the for block does NOT run.
Can you do something like that?
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