[Rd] cat with backspace and newline characters

[Prof J C Nash (U30A)]

Over the years, this has been useful to me (not just in R) for many
nonlinear optimization tasks. The alternatives often clutter the screen.

> On 13-11-06 06:00 AM, r-devel-request at r-project.org wrote:

> People do sometimes use this pattern for displaying progress (e.g. iteration counts). 
>> 
>> 


As this looks like a "terminal" matter, the first level solution may be
to take a couple of examples and prepare a table of what happens on the
most used platforms, including in things like RStudio and ESS. Might be
a good issue for Rwiki, as I'm sure few of us have all the choices.

I can generally live with warning users when the iteration display may
display oddly. Perhaps others have more stringent requirements, but if
documentation is enough, we can avoid fixing something that is more or
less outside R and may be unnecessary work. And documented examples can
also show us if things are changing.

JN