Does anyone understand TXTDIRTY?

Does anyone understand TXTDIRTY?

[Peter Stephenson]

Our terminal attributes bits have a flag TXTDIRTY set when certain
operations are done that involve text attributes.  I think the intention
is that if the attribute has a more global effect (such as turning off
too many things) we can recover by turning back on the ones that should
still be on.  So far so good.

However, the way it's called suggests we don't need it as a flag in the
string, it could be passed straight to tsetcap().  I thought perhaps if
the termcap capability didn't exist, it would arrange for something to
happen later.  But that doesn't make sense: the change needs to happen
right at that point, not later.  So as far as I can tell it could simply
be passed in as a flag.

Partly this is prompt by the thought that the zle_refresh code needs to
do something similar.  I haven't quite worked out whether
settextattributes() as it now exists will do the right thing.
Certainly it's forerunner (essentially the same code but called less
often) did, but there are now more tests in front to see if we really
need to change things around.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070