itensor: components



Hello all,

while trying to repair the broken components function in the itensor package I
struggle with the concept of "indexed objects". The manual (MIT/LCS/TM-167)
pg.13 says:

,,In ITENSR a tensor is represented as an "indexed object" . This is a
function  of  3  groups  of  indices  which  represent   the  covariant,
contravariant  and  derivative  indices." and ,,...the symbolic function 
representing  the tensor".

I can't realize the existence of such function wrt to itensor.lisp. It seems,
that the currently not working function components() contains some leavings of
an old implementation of indexed objects (i.e.the properties _TEXPRS_ and
_TSUBR_ ). These properties only appear in components and they are pretty
unused... (as far as I can see)

Is there anybody out there who could give me a hint where to find informations
about the implementation of _indexed objects_ in Macsyma? 

Thanks,
Wolfgang Zocher