Guido van Rossum <gu...@python.org> added the comment: On Mon, Feb 22, 2010 at 6:51 PM, Jeremy Hylton <rep...@bugs.python.org> wrote: > There's no reason we couldn't revise the language spec to explain that > except clauses and comprehensions are block statements, i.e. > statements that introduce a new block.
However (even apart from the below example) it would be tough to implement cleanly in CPython. > For the except case, there would be some weird effects. > > y = 10 > try: > ... > except SomeError as err: > y = 12 > print y # prints 10 > > In the example above, y would be a local variable in the scope of the > except handler that shadows the local variable in the block that > contains the try/except. It might be confusing that you couldn't > assign to a local variable in the except handler without using a > nonlocal statement. Yeah, there are all sorts of problems with less-conspicuous nested scopes like this, for a language that defaults to local assignment like Python. Hence the horrible hacks. >> As long as we don't have nested blocks, I think it's okay to see the >> limitation on (implicit or explicit) "del" of a cell variable as a compiler >> deficiency and fix that deficiency. > > The general request here is to remove all the SyntaxErrors about > deleting cell variables, right? Instead, you'd get a NameError at > runtime saying that the variable is currently undefined. You'd want > that change regardless of whether we change the language as described > above. Yeah, if we could kill those SyntaxErrors we can leave the rest as is. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue4617> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
