On Wed, Jul 16, 2008 at 3:11 PM, Nathaniel E. Powell
<nathan.powell at agilix.com> wrote:
> I am writing a program which uses Maxima for processing, but I also want
> people to be able to typeset expressions / equations in Maxima syntax. I
> want it to be typeset exactly as they type it in rather than being an
> evaluated or simplified version. One solution to this problem I've found is
> to turn off simplification:
>
> simp : false;
>
> and then prepending all of the function calls with the ' operator, which
> prevents things like 1+1 or integrate(x,x) from being simplified. Then, I
> put this expression inside of the Tex function call.
>
> I am wondering if there is a way to avoid having to search for all of the
> function calls and prepend them with a '. In order for them to be properly
> unevaluated (but still properly converted to Tex). I'm wondering if there is
> a global variable switch that does this. I looked around the documentation,
> but I must have missed it if it's there.
>
> I have tried surrounding the expression with '(), but this results in the
> function calls not being converted to Tex properly.
To prevent evaluation, try reading an expression from the console
via the Maxima function readonly or the Lisp function MREAD.
MREAD takes one argument which is an input stream,
*STANDARD-INPUT* or some stream opened by the Maxima
function openr.
About needing the ' to get appropriate tex output, what's going on here
is that so-called verb operators do not have the same TeX properties as
the corresponding nouns. I think that's a bug.
I thought about ways to work around that and copying TeX properties
doesn't work as expected. The following is the best I could come up with.
nounify_stuff (e) :=
(for x in '[diff, product, sum, integrate, binomial, limit]
do e : subst (nounify (x), verbify (x), e), e)$
which has the effect of sticking the ' on the operators listed there.
(I picked those 6 because they are the only ones, so far as I can tell,
which need nounification for TeX. There could be others, I guess.)
So here's what I get ...
simp : false;
foo : readonly ();
1 + 1 + sin(x) + diff(sin(x), x, 1) + integrate(sin(x), x); <--- I
typed it in
tex (foo);
=> $$1+1+\sin x+{\it diff}\left(\sin x , x , 1\right)+{\it integrate}
\left(\sin x , x\right)$$
tex (nounify_stuff (foo));
=> $$1+1+\sin x+{{d+^{1}}\over{d\,x^1}}\,\sin x+\int {\sin x}{\;dx}$$
Note that the diff expression has to be written with the explicit
degree 1 (which is ordinarily tacked on by simplification).
Without the degree, the TeX code for diff gets confused.
I don't know what you'e doing exactly, but I'll guess that you might
want to just write a custom top-level read-print loop in Lisp to get
more predictable control over simplification and evaluation.
In any event, HTH.
best
Robert Dodier