Subject: Maxima error when having strings in terms
From: Richard Fateman
Date: Sat, 20 Mar 2010 10:49:52 -0700
When macsyma was first written, there were no strings in lisp.
However, you can use arbitrary names for variables, like x, or _x_ or
This\ is\ a\ name.
So the lack of strings should not be a problem at all.
Oliver Kullmann wrote:
> Hello,
>
> the following nasty behaviour of Maxima we encountered
> when applying Maxima to statistical problems, where
> strings naturally show up:
>
> Maxima 5.20.1 http://maxima.sourceforge.net
> using Lisp ECL 9.12.3
> Distributed under the GNU Public License. See the file COPYING.
> Dedicated to the memory of William Schelter.
> The function bug_report() provides bug reporting information.
> (%i1) is("x">0);
> Maxima encountered a Lisp error:
> "x" is not of type LIST.
> (%i2) is(f("x")>0);
> Maxima encountered a Lisp error:
> "x" is not of type LIST.
> (%i3) declare(f, posfun);
> (%i4) is(f(1) > 0);
> (%o4) true
> (%i5) is(f("x") > 0);
> Maxima encountered a Lisp error:
> "x" is not of type LIST.
>
> This seems like a clear bug to me, and hopefully something can be done
> (otherwise our statistics application seem to become very clumsy, always
> having to translate strings into, say, numbers).
>
> Oliver
>
>