[Maxima-discuss] (displa-def $ket dimension-match "|" ">")

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

Hi list,

I played with qm-maxima a bit - links:

  https://github.com/QMeqGR/qm-maxima
  https://github.com/QMeqGR/qm-maxima/blob/master/qm.lisp
  https://sourceforge.net/p/maxima/mailman/message/58827564/

and I saw that it displays kets in a nice way, like this:

  ket([a,b]);    /* |a, b> */

The code that implements that is in qm.lisp. I found it hard to
understand, and I tried to rewrite it. I got this:

  (setf (get  'ket 'dissym) '((#\|) . (#\>)))
  (setf (get '$ket 'dimension) 'dimension-ket)
  (defun dimension-ket (e so-far)
    (dimension-match
     `((ket) ,@(cdadr e))
     so-far))

and when I was trying to understand `dimension-match' I stumbled on
`displa-def', and I tested this, on a clean Maxima:

  (displa-def $ket dimension-match "|" ">")

I got the impression that this is a high-level way to make ket([a,b])
be displayed as "|a, b>". Am I right? Or the code with two `setf's and
a `defun' is better? Why?



Now my main question. I've been using some objects - let me call them
"ccc"s - that I would like to display in a special way, as:

  ccc(x,y,z);   /* <x:y:z> */

This code almost does what I want:

  to_lisp();
    (displa-def $ket dimension-match "|" ">")
    (displa-def $aaa dimension-nary ":")
    (displa-def $bbb dimension-match "<" ">")
    (to-maxima)
  ket(a,b);      /* |a, b> */
  ccc([args]) := bbb(apply('aaa, args))$
  ccc(x,y,z);    /* <x:y:z> */

but with this definition for ccc the internal representation of
ccc(x,y,z) is:

  (($BBB SIMP) (($AAA SIMP) $X $Y $Z))

and my functions to manipulate "ccc"s would be easier to write if the
internal representation of ccc(x,y,z) would be just this,

  (($CCC SIMP) $X $Y $Z)

but for that the "displa"ying of "ccc"s needs to be more complex - it
needs to add the ":"s as separators AND the "<" and the ">" at the
extremities. How can I do that?

  Thanks in advance! =)
    Eduardo Ochs
    http://anggtwu.net/eev-maxima.html