Using lisp displa to view local variables

You really need to review basic Lisp semantics.

For a normal function f, (f x (+ a b)) does not pass the expressions x and
(+ a b) to f, but their values.  So f has no way of "retrieving" the
expressions you used.

For a macro, (f x (+ a b)) passes the unevaluated expressions.

You need to write a macro that, called as (f a b), returns something like
(progn (myprint 'a a) (myprint 'b b)), where myprint takes *as separate
arguments* the name and the value of each expression.

            -s

On Tue, Jul 26, 2011 at 16:31, Edwin Woollett <woollett at charter.net> wrote:

> On July 26, 2011, Stavros Makrakis wrote:
> **************************
>
> That all looks correct to me.  If you want something like (ldisplay x y z)
> to print x=3, y=3, etc., then ***ldisplay*** needs to be a macro.
> ******************************************
> I have tried using  (dolist (xk xx)  body) with and without
> (defmacro...) with no success. I obviously need to study up
> on Lisp macros. Where do I put the commas when my
> starting point is a lisp list like xx?
> ------------------------------**------------------------------**------
> MAXIMA> (dolist (bk '(1 2 3))
>               (print bk))
>
> 1
> 2
>
> 3
> NIL
>
> MAXIMA> (defun ldisplay (&rest xx)
>     (dolist (xk xx) ($display_value xk)))
>
>
> LDISPLAY
>
> MAXIMA> (defun f1 ()
>  (let ((a1 'aa) (s1 "my string") (l1 '(a b c)))
>        (mtell "local")
>        (ldisplay s1 l1 a1)
>        (mtell "bye")))
>
> F1
>
> MAXIMA> (f1)
>
> local
> xk = my string
> xk = (a, b, c)
> xk = aa
> bye
> NIL
>
> MAXIMA> (defmacro $ldisplay (&rest xx)
>     (dolist (xk xx) ($display_value xk)))
>
> $LDISPLAY
>
>
> MAXIMA> (defun f1 ()
>  (let ((a1 'aa) (s1 "my string") (l1 '(a b c)))
>        (mtell "local")
>        ($ldisplay s1 l1 a1)
>        (mtell "bye")))
>
> F1
>
> MAXIMA> (f1)
>
> local
> xk = s1
> xk = l1
> xk = a1
> bye
> NIL
>
> MAXIMA> (defmacro $ldisplay (&rest xx)
>     (dolist (xk ,xx) ($display_value xk)))
>
>
> Maxima encountered a Lisp error:
> Error in READ [or a callee]: A comma has appeared out of a backquote.
> Error in EVAL [or a callee]: The variable XX is unbound.
> Error in EVAL [or a callee]: The variable XK is unbound.
>
> MAXIMA> (defmacro $ldisplay (&rest xx)
>     (dolist (xk xx) ($display_value ,xk)))
>
>
> Maxima encountered a Lisp error:
> Error in READ [or a callee]: A comma has appeared out of a backquote.
> Error in EVAL [or a callee]: The variable XK is unbound.
>
> ------------------------------**------
>
> Ted
>
>
>