c-code generation



Hello,

I wrote a maxima function expr2c() to generate optimized C-code from maxima
expressions. One can call it like

expr2c("test", "double x, double y", diff((x^4 + 2 * y) * (x ^ 2 + y) * x, x));

I'm new to maxima, so the code is pretty crude:

printdecl(vars) := (
        sprint("double", first(vars)),
        for v in rest(vars) do sprint(",", v),
        sprint(";"))$

printdef(expr) := sprint(first(expr), "=", second(expr), ";")$

block2c(expr) :=
        if ?equal(op(expr), block) then (
                printdecl(first(expr)),
                for d in reverse(rest(reverse(rest(expr)))) do printdef(d),
                sprint("return", string(last(expr)), ";"))
        else
                sprint("return", string(expr), ";")$

expr2c(funcname, argstr, expr) := (
        sprint("double", funcname, "(", argstr, ") {"),
        block2c(subst(pow, "^", optimize(expr))),
        sprint("}", "
"))$


Unfortunately, C does not allow to use e.g. %5 as a variable name,
so currently I need to run the result through "sed s/%/_/g".
Any ideas how to replace the % characters in maxima?

regards,
 Johannes

BTW: Thanks a lot for your work on this great open source project!