for-else

[pauldraper]

I am once again asking for for-else loops.

has_ts = False
for file in files:
    if file.endswith(".d.ts"):
        has_ts = True
        break
if not has_ts:
    # TODO
    pass

Whereas this can be much more succient.

for file in files:
    if file.endswith(".d.ts")
        break
else:
    # TODO
    pass

Coming from Python, it was surprising to see this loop construct unsupported. AFAIK there is no reason (e.g. Turing completeness, semantics incompatibility) to not support for-else.