[Maxima-discuss] Edrxbox: a simpler way to write `dim-*' functions

[Eduardo O. <edu...@gm...>]

Hi list,

this page

  https://anggtwu.net/maxima-edrxbox.html

describes a library that lets us write `dim-*' functions like this,

--snip--snip--
(setf (get '$antideriv 'dimension)
      'dim-antideriv)

(defun dim-antideriv-core (a b c)
  (let* ((a-box      (edrxbox-from-form a))
         (b-box      (edrxbox-from-form b))
         (c-box      (edrxbox-from-form c))
         (a-height   (getf a-box :height))
         (b-height   (getf b-box :height))
         (c-height   (getf c-box :height))
         (a-depth    (getf a-box :depth))
         (b-depth    (getf b-box :depth))
         (c-depth    (getf c-box :depth))
         (abc-height (max a-height (+ b-height b-depth 1)))
         (abc-depth  (max a-depth  (+ c-height c-depth)))
         (b-y        (- abc-height b-height))
         (c-y        (- c-depth abc-depth))
         (vbar-x     (getf a-box :width))
         (bc-x       (+ vbar-x 1))
         (vbar-box   (list :width 1 :height abc-height :depth abc-depth
                           :result `((d-vbar ,abc-height ,abc-depth)))))
    (edrxboxvars-push-x-y-edrxbox 0      0 a-box)
    (edrxboxvars-push-x-y-edrxbox vbar-x 0 vbar-box)
    (edrxboxvars-push-x-y-edrxbox bc-x b-y b-box)
    (edrxboxvars-push-x-y-edrxbox bc-x c-y c-box)
    (edrxboxvars-push-x-y-end)))

(defun dim-antideriv (form result)
  (let* ((args (rest form))
        (a (first  args))
        (b (second args))
        (c (third  args)))
    (if (not (= (length args) 3))
(dimension-function form result)
(run-in-edrxbox-dim
(dim-antideriv-core a b c)))))
--snip--snip--

I find that style much easier to understand and debug that the
one here,

  https://sourceforge.net/p/maxima/bugs/4639/

and much, much, MUCH easier to understand and debug than the style
of the functions in displa.lisp.

The page has lots of examples and screenshots.
All feedback very welcome!

  Cheers =),
    Eduardo Ochs
    https://anggtwu.net/maxima-edrxbox.html
    https://anggtwu.net/eev-maxima.html