Redirecting standard out in a single namespace

[Bengt Richter]

On 23 Jan 2006 04:00:40 -0800, "Fuzzyman" <fuzzyman at gmail.com> wrote:

>
>Bengt Richter wrote:
>
[...]
>> It wouldn't be shadowing, but I suppose you could replace sys.stdout with
>> a custom object whose methods check where they were called from.
>> Then you could give the object initialization parameters as to which namespace
>> you want to have the effect in, and/or methods to control the action or turn
>> it on or off etc. BTW, how about stderr?
>>
>
>Redirecting stderr is identical in concept to redirecting stdout.
>
Yeah, just reminding, in case you need to do that too ;-)

>The following in the write method of the custom out object works :
>
>    sys._getframe(1).f_globals['__name__']
>
>sys.stdout.write is *always* called from at least one frame deep in the
>stack - so it works.
Yes, that's about what I had in mind, not being able to think of an alternative
(other than the obvious one of using something other than print in the module
where you want to redirect, either by hand or by effective source rewrite one way
or another to translate print statments into e.g. myprint('the', 'print', 'args') or such.
You could do source preprocessing or translating at the AST level, or you could do byte code munging.
Nothing too nice.

>
>However the Python docs say of sys._getframe :
>
>    This function should be used for internal and specialized purposes
>only.
>
>Might this approach be brittle ?
>
In what sense? I guess it ought to work for the version it's defined for, but the advice is there.
Maybe we can get something more specific from the author of the above doc snippet ;-)

Regards,
Bengt Richter