[Python-Dev] PEP 340: Breaking out.

[Delaney, Timothy C (Timothy)]

Aahz wrote:

> My standard workaround is using exceptions, but I'm not sure how that
> interacts with a block:
> 
>     try:
>         for name in filenames:
>             with opened(name) as f:
>                 if f.read(2) == 0xFEB0:
>                     raise Found
>     except Found:
>         pass

For any sane block iterator, it will work as expected. However, an evil
block iterator could suppress the `Found` exception.

A sane block iterator should re-raise the original exception.

Tim Delaney