From help-octave-request at bevo dot che dot wisc dot edu Mon Jan 12 08:40:13 2004
Subject: Re: color choice in plotting
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Christoph Dalitz <christoph dot dalitz at hs-niederrhein dot de>
Cc: help-octave at bevo dot che dot wisc dot edu
Date: Mon, 12 Jan 2004 08:36:45 -0600

On 12-Jan-2004, Christoph Dalitz <christoph dot dalitz at hs-niederrhein dot de> wrote:

| On Fri, 9 Jan 2004 16:00:32 -0600
| "John W. Eaton" <jwe at bevo dot che dot wisc dot edu> wrote:
| > 
| > This has come up many times, and the answer is that Octave does not
| > support "linetype" as an option to gplot and probably never will.  The
| > problem is that since Octave has to parse the command, it creates a
| > maintenance problem when gnuplot changes (the linetype option was not
| > always a part of gnuplot, for example).
| > 
| I understand that Octave needs to identify and expand its variables in
| the gplot statement, but why can Octave not send the rest of the gplot
| statement unaltered to gnuplot?

Because then you have to always be explaining to people why this fails:

  my_line = 4;
  gplot my_data with lines my_line;

Actually, this currently works, because Octave *does* interpret the
entire gnuplot command line, and everything except keywords like
"with" and "lines" is interpreted.  But you could make the case that
"lines" should also be allowed to be a variable, so maybe even what we
have now is not good enough.

Also, you will have to do at least some parsing to determine how to
break up this type of command:

  gplot data_1 w l lt 1, data_2 w l lt 2

It will be tricky to try to pass parts of the plot command verbatim
and still correctly figure out which of the possible commas in the
command separate subplot clauses.

So, for the Nth time: exposing gplot and friends was a horrible idea
from the point of view of maintenance and I'd like to deprecate and
eventually remove them.

| Could you give me a hint where to look in the Octave sources in order
| to investigate this in more detail?

Try lex.l, parse.y, pt-plot.{h,cc}.

jwe



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