Guido van Rossum wrote:
> Anyway, perhaps we should provide this most general template:
>
> @do_template
> def with_decimal_context():
> oldctx = decimal.getcontext()
> newctx = oldctx.copy()
> decimal.setcontext(newctx)
> yield newctx
> decimal.setcontext(oldctx)
>
> To be used like this:
>
> do with_decimal_context() as ctx:
> ctx.prec += 2
> # change other settings
> # algorithm goes here
For the 'with' keyword, and the appropriate __enter__/__exit__ methods on
decimal Contexts, this can be written:
with decimal.getcontext() as ctx:
ctx.prec += 2
# change other settings
# algorithm goes here
# Pre-with context guaranteed to be restored here
The decimal.Context methods to make this work:
def __enter__(self):
current = getcontext()
if current is self:
self._saved_context = self.copy()
else:
self._saved_context = current
setcontext(self)
def __exit___(self, *exc_info):
if self._saved_context is None:
raise RuntimeError("No context saved")
try:
setcontext(self._saved_context)
finally:
self._saved_context = None
Cheers,
Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://boredomandlaziness.blogspot.com
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