Sanitize is not fool proof (yet) .Sanitize2 seems to work as advertized.

Dan Stanger wrote:
> Hello Michel,
> Are you aware that of the syntax f('x):=... creates a function which
> does not evaluate x when called?
> You may find that useful.  Did you download the comercial macsyma demo
> from Dr. Fateman's web site?
> It contains the reference manual for the Macsyma language, which I
> think you would find helpful.
> Dan Stanger
No, but I did know about f(x)::= which is the same I presume. Anyway
this is irrelevant for the example:

h('s,t):=s[t]$
h(r,1);
    r_1
h(t,1);
t evaluates to 1
Improper name or value in functional position.
#0: h(s=t,t=1)
 -- an error.  To debug this try debugmode(true);

Now I ***know*** one can rewrite this example so that it works (e.g. 
Richard has given a fairly generic way
using ?gensym()). But this is not my point. The  ***user should not have
to worry about this***.  After all
this is a ***completely trivial one line program***. It should work as 
expected.

Michel