High level user macro (howto?)

[Maurice Diamantini dom <mdiam@chello.fr>]

Bonjour à tous,

One thing is missing in context (or not documented in reference manual?)
is a standard and easy way to build arbitrary parametrised high level 
macros.

For exemple, instead of
    \def\myCommand#9{...}
That I should call by
    \myCommand{param1}{param2}{...} {param9}

Id'like too keep default value for most of the parameters but param7
and write something like:

    \myCommand[param7=value7]{body}

In LaTeX, there is a package keyval for doing this
And context use this everywere, but I haven't seen anything for
a user beeing able to do this.

This is the base for building arbitrary complex user commands with
some defauld behavior, and then, if this personal macro is usefull
enough, building some user contribution library.

As a true exemple, see a latex package I've written some years
ago for drawing uml diagramms whith LaTeX command (using PsTricks).
This file is available at
   http://www.ensta.fr/~diam/latex/pst-uml/pst-uml-981218-09h41.tar.gz
(should now be available on CTAN too)
See documents for the samples (in french but the samples are in LaTeX 
and
drawing are in "picture" !)

One of the first exemple I'd like is some command to put some little
table as caractere in a line (see that as some personalised box):

   start of line
   $-$\myStack[border=1ex,baseline=0.5]{
       aaa & bbb \\
       aaa & bbb \\
       aaa & bbb
   }$-$
   end of line

Or a little command to draw some picture, with default but modifiable
parameters:

   $-$\myzigzag[dir=down,linewith=1pt,color=red,with=3\em]$-$

Using Metafun.


Cordialement,

-- Maurice