[Python-ideas] "while ... try" - block or "for ... try" - block

Wed Jan 11 18:06:58 CET 2012

2012年1月11日 Manuel Bärenz <manuel at enigmage.de>:
> I propose two new control flows for Python:
>> "while ... try":
>> while expr try:
>    suite1
> except SomeException:
>    suite2
> else:
>    suite3
>> This executes suite1 as long as handled exceptions are thrown and expr
> is True.
> * If an unhandled exception is thrown, it passes the exception on to the
> surrounding or the stack.
> * If no exception occurs, life goes on as normal, suite3 is executed and
> execution goes on afterwards.
>> The control flow is thus equivalent to:
>> while expr:
>    try:
>        suite1
>    except SomeException:
>        suite2
>    else:
>        suite3
>        break

Aside from anything else, there is the problem that
while:
 suite
else:
 suite
is already valid Python
Your proposed syntax changes the semantics of "else" after "while"
(and the same applies to "for ... else".
-- 
Arnaud