Re: beginner’s question with Maxi ma

Some comments...

If you  declare("-",alphabetic), you can avoid problems by writing a space
before and after the minus sign, e.g., *- a* and *a - b* rather than *-a*
and *a-b*.

It's nice to see someone taking advantage of Maxima's extensible syntax, but
declaring standard operator characters to be alphabetic is bound to cause
problems:

   - Maxima's output form doesn't take it into account, so you can't use
   *save/load*.

declare("-",alphabetic)$

string(a - b) >>> a-b (a symbol, not an expression)

parse_string(string(a - b))+b  >>>    b + a-b

op(parse_string(string(a - b))) >>>
   part: argument must be a non-atomic expression; found a-b


   - Libraries written in the Maxima language are likely not to read in
   correctly.
   - It's confusing for users that 3e-3 is a number, but -3e-3 is a symbol
   (the "-" in the exponent is handled by the number parser, which ignores the
   alphabetic declaration).

It's better practice to write bigfloat numbers in bigfloat notation
directly, e.g., *1.234b-3, *or to convert exact numbers, e.g., *bfloat(1234
* 10^ - 6), *instead of converting floating-point numbers, e.g.,
*bfloat(1.234e-3)*. In your particular example, though, float precision is
enough, so it doesn't matter.

I don't understand why you're writing S as a memoizing function.

        -s

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