Re: Loop into parametric plot or splot

[Ethan M. <merritt@u.washington.edu>]

On Sunday 18 March 2007 13:41, Brouard Nicolas wrote:
> Trying to still improve the drawings I tested your for loop, but in
> parametrics mode something like:
>    plot [t=0:2.*pi] for[i=0:2] sin(t+i),t
> will give strange results (not stupid result) and something like
>    plot [t=0:2.*pi] for[i=1:2] sin(t+i),t
> outputs a warning
>   parametric function not fully specified

Hmm. Yes, I can believe that.
Both of my recent plot extensions (iteration and '+' as a pseudo-file)
came with a caveat that I wasn't familiar enough with the parametric
plot modes to test them thoroughly.

The problem is poorly chosen syntax for parametric plots, syntax
that we are now stuck with even though it is a pain to parse correctly.
In "normal" plot commands a comma indicates the end of one plot and 
the beginning of another.  In parametric plot commands the comma means
something else entirely.  The iteration code is not smart enough to
distinguish the two cases.  Fixing this will probably be a headache,
but I'm sure it's possible.


-- 
Ethan A Merritt