Maxima interface for CL hash tables

I'm not going to puzzle my way though this, but the function listarray 
(defined in  marray.lisp) has a clause 

   ((hash-table-p ary)
               (let (vals (tab ary))
                       ....
I'm not convinced that there is a Maxima interface to CL hash tables:

(%i1) a[4] : 42;
(%o1) 42

(%i2) :lisp(trace hash-table-p hasher);

(%i2) listarray(a);
  1> (HASH-TABLE-P $A)
  <1 (HASH-TABLE-P NIL)
  1> (HASHER (4))
    2> (HASHER NIL)
    <2 (HASHER 0)
  <1 (HASHER 4)
(%o2) [42]


(%i3) arrayinfo(a);
  1> (HASH-TABLE-P $HASHED)
  <1 (HASH-TABLE-P NIL)

(%o3) [hashed,1,[4]]

(%i4) :lisp(hash-table-p (mget '$a 'hashar));
  1> (HASH-TABLE-P #:G33532)
  <1 (HASH-TABLE-P NIL)
NIL

Barton