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C00002 00002	ah, ha!! i talk about sexprs and lists as abstract data structures
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ah, ha!! i talk about sexprs and lists as abstract data structures
with binary trees as a  possible representation( dotted pairs are 
another representation). the point of keeping sexprs and lists  separate is that
after describing lists as abstract d.s( with their associated 
constructors, selectors and predicates), THEN you note that
if you want to represent them on a LISP machine you:
1. must represent lists in terms of the underlying representation (sexprs)

2.must specify representaitons of the basic list-manipulations( list, null, etc)
interms of the LISP primitves( car, cdr, etc..)

3.must specify i/o transformations to read and print list notation.

and this is the easy way to introduce the discussion of representation
of abstract data structures.