On Sun, Aug 27, 2017 at 11:19:20AM -0400, Yury Selivanov wrote: > On Sun, Aug 27, 2017 at 6:08 AM, Stefan Krah <[email protected]> wrote: > > On Sat, Aug 26, 2017 at 04:13:24PM -0700, Nathaniel Smith wrote: > >> It's perfectly reasonable to have a script where you call > >> decimal.setcontext or np.seterr somewhere at the top to set the > >> defaults for the rest of the script. > > > > +100. The only thing that makes sense for decimal is to change > > localcontext() > > to be automatically async-safe while preserving the rest of the semantics. > > TBH Nathaniel's argument isn't entirely correct. > > With the semantics defined in PEP 550 v4, you still can set decimal > context on top of your file, in your async functions etc. > > and this: > > def bar(): > decimal.setcontext(ctx) > > def foo(): > bar() > # use decimal with context=ctx
Okay, so if I understand this correctly we actually will not have dynamic scoping for regular functions: bar() has returned, so the new context would not be found on the stack with proper dynamic scoping. > and this: > > async def bar(): > # use decimal with context=ctx > > async def foo(): > decimal.setcontext(ctx) > await bar() > > The only thing that will not work, is this (ex1): > > async def bar(): > decimal.setcontext(ctx) > > async def foo(): > await bar() > # use decimal with context=ctx Here we do have dynamic scoping. > Speaking of (ex1), there's an example that didn't work in any PEP 550 version: > > def bar(): > decimal.setcontext(ctx) > yield > > async def foo(): > list(bar()) > # use decimal with context=ctx What about this? async def bar(): setcontext(Context(prec=1)) for i in range(10): await asyncio.sleep(1) yield i async def foo(): async for i in bar(): # ctx.prec=1? print(Decimal(100) / 3) I'm searching for some abstract model to reason about the scopes. Stefan Krah _______________________________________________ Python-Dev mailing list [email protected] https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com