[Python-Dev] PEP 548: More Flexible Loop Control

[Chris Angelico]

On Wed, Sep 6, 2017 at 10:11 AM, R. David Murray <rdmurray at bitdance.com> wrote:
> I've written a PEP proposing a small enhancement to the Python loop
> control statements.  Short version: here's what feels to me like a
> Pythonic way to spell "repeat until":
>
>     while:
>         <do stuff>
>         break if <done condition>
>
> The PEP goes into some detail on why this feels like a readability
> improvement in the more general case, with examples taken from
> the standard library:
>
>      https://www.python.org/dev/peps/pep-0548/

Is "break if" legal in loops that have their own conditions as well,
or only in a bare "while:" loop? For instance, is this valid?

while not found_the_thing_we_want:
    data = sock.read()
    break if not data
    process(data)

Or this, which uses the condition purely as a descriptor:

while "moar socket data":
    data = sock.read()
    break if not data
    process(data)

Also - shouldn't this be being discussed first on python-ideas?

ChrisA