[Texmacs-dev] Re: Gnuplot Interface change and (poor man's ?) spreadsheet feature

[Joris van der Hoeven]

Hi Stephan,

On Thu, 17 Feb 2005, Stephan Mucha wrote:
> Spreadsheet feature
> ===================
> Very long time ago I asked for a Spreadsheet-like facility and at the
> moment I could benefit much from such a feature again for a certain
> problem.
>
> My question is: Is there already any way to get a changed input line
> of a CAS session re-evaluated, resulting in changed values for
> dependend lines below, maybe with the help of "mutators" as in the
> following example?
>
> original          changed
>
> i1: a=1           i1: a=10
> o1: 1             o1: 10
> i1: b=2*a         i2: b=2*a
> o2: 2             o2: 20
>
> maybe some keystroke or the like to update dependencies is needed
> after changing first input line. of course, in a simple version, the
> hole CAS variables had to be cleared and all input lines evaluated
> again to avoid the need for management of double used variables,
> otherwise the last assignment to each variable would hold:
>
> i1: a=1           i1: a=1
> o1: 1             o1: 1
> i1: b=2*a         i2: b=3*a
> o2: 2             o2: 300
> i3: a=100         i3: a=100
> o3: 100           o3: 100
>
> If there is such a feature, do you have an idea, how to implement at
> least this simple version? I would try then, if I can, but not in C++
> as I have no idea of it - but I have read a lot about scheme and lisp
> during the past months, maybe I will be able to apply it :-)

Yes, it would be very useful to implement a function "re-evaluate all"
or something like that. I just never happened to have time for that.
The idea would simply be to re-evaluate the next input field whenever
the evaluation of the previous one terminates. See mutate-plugin-result
for what is currently done.

Unfortunately, a lot of the session-stuff is still managed at the C++
level for the moment. This has eventually to be rewritten in Scheme.

> Gnuplot interface
> =================
> Can you tell me a good pointer to CVS stuff documentation, I never
> used it because I'm not really a programmer ...

I bought a small O'Reilly book.
Maybe someone has a suggestion where to find good documentation on the web.