On Tue, Mar 31, 2020 at 2:41 AM Serhiy Storchaka <storchaka@gmail.com> wrote:
31.03.20 01:32, Christopher Barker пише:
In case Serhiy's answer wasn't clear: context managers can be written to handle exceptions (within their context) in any way you see fit.
that is: the method: | | |__exit__(||self||, exc_type, exc_value, exc_traceback):|
get the exception, and information about it, of one is raised, so you can handle it anyway you want.
Actually I meant the opposite.
I think I was thrown by the use of the example "my_context" -- that is, if you are writing a conrtect manger, you can handle exceptions any way you like. If you are using an existing one, then, yes:
the context manager does not silence a raised exception, so control flow is never passed to the statement past the with block if an exception is raised inside the with block.
was_not_raised = False with my_context(): do_something_sensitive() was_not_raised = True if was_not_raised: print("We're all safe.")
You do not need a special syntax for this.
but we don't need special syntax for "else" on a for or while loop (or try block) either, you could always set a sentinel for those too. which to me is a case for adding else to a "with" block as well, for all the same reasons it's there for the other block construct. Though I don't think I'd advocate it in this case, as the Exception is not really a clear part of the context manger API, like "break" is to the loops. -CHB -- Christopher Barker, PhD Python Language Consulting - Teaching - Scientific Software Development - Desktop GUI and Web Development - wxPython, numpy, scipy, Cython