Tamas Papp <tkpapp at gmail.com> writes:
> Hi,
>
> Is there a quick & easy way to translate results of calculations to
> Common Lisp (or any Lisp) sexps? Eg a+b*c would become (+ a (* b c)),
> etc. I need this because I would like to use analytical results,
> calculated with Maxima, in a CL program, and I don't want to transcribe
> it manually if that can be avoided.
>
> Best,
>
> Tamas
If you use ?print(expr), this is equivalent to calling (print XX) in
Common Lisp, where XX is some cons representing expr. For example:
(%i1) first(solve(x^3+3*x+4 = x, x));
sqrt(3) %i 1
2 (---------- - -)
2 sqrt(29) 1/3 sqrt(3) %i 1 2 2
(%o1) x = (---------- - 2) (- ---------- - -) - ---------------------
3/2 2 2 2 sqrt(29) 1/3
3 3 (---------- - 2)
3/2
3
(%i2) ?print(%o1)$
((MEQUAL SIMP) $X
((MPLUS SIMP)
((MTIMES SIMP)
((MEXPT SIMP)
((MPLUS SIMP) -2
((MTIMES SIMP) 2 ((MEXPT SIMP) 3 ((RAT SIMP) -3 2))
((MEXPT SIMP) 29 ((RAT SIMP) 1 2))))
((RAT SIMP) 1 3))
((MPLUS SIMP) ((RAT SIMP) -1 2)
((MTIMES SIMP) ((RAT SIMP) -1 2) ((MEXPT SIMP) 3 ((RAT SIMP) 1 2)) $%I)))
((MTIMES SIMP) ((RAT SIMP) -2 3)
((MEXPT SIMP)
((MPLUS SIMP) -2
((MTIMES SIMP) 2 ((MEXPT SIMP) 3 ((RAT SIMP) -3 2))
((MEXPT SIMP) 29 ((RAT SIMP) 1 2))))
((RAT SIMP) -1 3))
((MPLUS SIMP) ((RAT SIMP) -1 2)
((MTIMES SIMP) ((RAT SIMP) 1 2) ((MEXPT SIMP) 3 ((RAT SIMP) 1 2)) $%I)))))
To translate to a formula you can use in Common Lisp, you'll need to
change MPLUS to +, MTIMES to * etc.
I presume that you have just a few such formulas. In which case, a
find+replace on the text is probably the most sensible. Trying to do it
programmatically, I can imagine I'd get tripped up by lots of corner
cases.
Rupert
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