[Patch] show input 2d

Dear Maxima community,

I' am new on this list, so I have first to introduce me.

My name is Waldemar, I' m a student of Physics Science

at the University of Karlsruhe, Germany.

I use Maxima in my study most for calculating some

Integrals, to solve some Equations and odes.

I was annoying of to have some mistakes at the input

(most forgot some brackets) which  yields to wrong answer.

So I thought it would be nice if Maxima can display me my

input in a pretty print form, so I can easily recheck if my

input was correct.

I went on and did some investigation in Maxima source code.

Luckily I find a way to implement this behavior and put a patch

together.



Usage of the patch:

Simply copy and paste the code bellow in an editor of your choice

and save the file as "input2d.lisp".

Then you can load the code in Maxima with:

load("input2d.lisp");

Now you are done. Try to enter some expression and let Maxima

evaluate it. See what occurs.

You can switch this behavior of by typing:

toggle_display_input_2d();

And switch on again, by typing again:

toggle_display_input_2d();

If you want that the input should be displayed in the middle of the

screen, just like the output you can set the global Lisp variable

*display-input-2d-leftjust* to nil by typing:

:lisp (setq  *display-input-2d-leftjust* nil)

This works only for command line Maxima and XMaxima.

Now when I reread my mail I think the global Lisp variable

*display-input-2d-leftjust* should be a Maxima variable something

like: $display_input_2d_leftjust to be more consistent with the output

variable $leftjust (what do you think?).



Finally I' m interesting in your feedback, what do you think about

this all?

I have to say I' m not a coder, so there are maybe some bugs, please

have a look in the code.

And on all Maxima developer a big thank you for Maxima!!!



Ok here is the code:

;;;;;;;;;;;;;;;;;input2d.lisp;;;;;;;;;;;;;;;;;;;;;;;;;;;

 (in-package :maxima)

(defvar *display-input-2d* t)
(defvar *display-input-2d-leftjust* t)
(defvar *alt-main-prompt* 'display-input-2d-main-prompt)

(defun $toggle_display_input_2d ()
  (cond (*display-input-2d*
     (setq *display-input-2d* nil)
     (setq *alt-main-prompt* nil)
     (format t "~% display-input-2d disabled ~%"))
    (t
     (setq *display-input-2d* t)
     (setq *alt-main-prompt* 'display-input-2d-main-prompt)
     (format t "~% display-input-2d enabled ~%")))
  *display-input-2d*)


(defun subst-by-atom (new old tree)
  (if (string-equal
       (format nil "~A" tree)
       (format nil "~A" old))
      new
      (if (atom tree) tree
      (cons (subst-by-atom new old (car tree))
        (subst-by-atom new old (cdr tree))))))


(defun subst-by-list (subst-list tree)
  (if (atom subst-list) tree
      (subst-by-list (cdr subst-list)
             (subst-by-atom (first  (car subst-list))
                    (second (car subst-list))
                    tree))))


(defun display-input-2d (input)

  ;;Substitutions list of the type: ((new1 old1) (new2 old2) ...)
  (let ((subst-list (list '((%INTEGRATE)  ($INTEGRATE))
              '((%DERIVATIVE) ($DIFF))
              '((%PRODUCT)    ($PRODUCT))
              '((%SUM)        ($SUM))
              '((%LIMIT)      ($LIMIT))
              '((%AT)         ($AT))))
    ($leftjust *display-input-2d-leftjust*))

    ;;Send the input expression to display.
    (displa
     (list '(mlable) (makelabel $inchar)
     ;;Do some substitutions for nicer looking outputs.
       (subst-by-list subst-list input)))))

(defun display-input-2d-main-prompt ()
  (format nil "~AIn[~D]> ~A"
      *prompt-prefix* $linenum *prompt-suffix*))


;;;Redifinition of two Maxima functions:
;;; - main-prompt ()
;;;     added an If condition.
;;; -  toplevel-macsyma-eval (x)
;;;     added an IF condition.
;;;Both functions were originally defined in macsys.lisp

(defun main-prompt ()
  ;; instead off using this STRIPDOLLAR hackery, the
  ;; MREAD function should call MFORMAT to print the prompt,
  ;; and take a format string and format arguments.
  ;; Even easier and more general is for MREAD to take
  ;; a FUNARG as the prompt. -gjc
  (declare (special *display-labels-p*))

  (if  *alt-main-prompt* (funcall  *alt-main-prompt*)

       ;;else default promt like in macsys.lisp
       (if *display-labels-p*
       (format nil "~A(~A~D) ~A"
           *prompt-prefix*
           (print-invert-case (stripdollar $inchar))
           $linenum
           *prompt-suffix*)
       "")))



(defun toplevel-macsyma-eval (input)
  (if *display-input-2d* (display-input-2d input))
  (meval* input))



 ;;;;;;;;;;;;;;;;;end of input2d.lisp;;;;;;;;;;;;;;;;;;;;;;



PS: sorry for my bad English.