Interpreting LISP: Programming and Data Structures, Second Edition

© Gary D. Knott 2017

Gary D. Knott, Interpreting LISP, 10.1007/978-1-4842-2707-7_7

7. Pictorial Notation

Gary D. Knott¹ 

(1)Civilized Software Inc., Silver Spring, Maryland, USA

Let us suppose the atom table and the number table are loaded as follows:

Then X is represented by the typed-pointer oa(3) and NIL is represented by the typed-pointer oa(0), both of which are negative integers. Remember that the type field in an atom table entry describes the type of the value of that ordinary atom. The S-expression (T . NIL) is represented by a positive integer j such that P _j .car = oa(1) and P _j .cdr = oa(0); that is (T . NIL) corresponds to j where ...