p:log feels clunky

Hello,

It seems clunky to have a sibling element to control logging behavior
over p:output / p:input;

* makes refactoring port names more difficult, e.g. change on
input/output means change in p:log

* its restricted just to input/outputs, I would like to see the output
at some 'out of band' point

I would propose something a bit more all encompassing, e.g. a p:log
attribute which could be placed on steps, inputs/outputs, and/or other
xproc elements

some examples;

<p:group log="href">
   ....
</p:group>

<p:choose log="href">
...
</p:choose>

<p:declare-step log="href">
....
</p:declare-step>

and of course input/output

<p:input log=""/>

we may even want to place these global type attributes in a different
namespace ?

no conviction here for this, but it becomes apparent in implementation
that p:log is a bit limited and an exetension attribute becomes
useful.

cheers, Jim Fuller