[Python-Dev] Example for PEP 343

[Raymond Hettinger]

> I don't see a call to setcontext() in the sin() example in the library
> reference. Is that document wrong? I thought that simply modifying the
> parameters of the current context would be sufficient.

The sin() example is correct.  The precision is changed and restored in
the current context.

However, for a general purpose wrapper, it is preferable to make a
context copy and then restore the context after the enclosed is run.
That guards against the enclosed block making any unexpected context
changes.

Also, since the wrapper is intended to work like a try/finally, it will
make sure the context gets restored even if an exception is raised at
some unexpected point in the middle of the computation.



Raymond