[Python-ideas] Except block for with-statement

[Matt Joiner]

That's a fantastic idea. As it stands context objects need to be done
manually if exception handling is desired during enter. The except here
could apply to the with statement only, since it's not possible to
differentiate at present. Either way +1 to some consideration of Carl's
proposal.
On Nov 20, 2011 10:43 AM, "Carl M. Johnson" <cmjohnson.mailinglist at gmail.com>
wrote:

> I was looking through the "What's New for Python 3.3" file and I saw this
> example code:
>
> try:
>    with open("document.txt") as f:
>        content = f.read()
> except FileNotFoundError:
>    print("document.txt file is missing")
> except PermissionError:
>    print("You are not allowed to read document.txt")
>
> and I thought it would be more elegant if you could drop the try.
>
> with open("document.txt") as f:
>    content = f.read()
> except FileNotFoundError:
>    print("document.txt file is missing")
> except PermissionError:
>    print("You are not allowed to read document.txt")
>
> I assume that this has already been proposed and rejected. Does anyone
> have a good explanation of why? ISTM that the with-statement is mostly just
> a way of abstracting out try-except blocks, so it might be nice to have a
> way of handling errors that pop up during the initialization phase instead
> of just the code-block phase.
>
> I guess one obvious counter argument is that naive programmers might think
> that the "except" applies to things in the block instead of just things in
> the initializer. But naive programmers think lots of wrong things. ;-)
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