Section 55
Want more of a challenge? View in iconic form (experimental)

       # SELF a mechanism for referring to parts of the message
       # Many choices for how to do this.
       # Could do it without special machinery by using the
       # standard A-B trick for giving e.g. a Turing machine
       # access to its own description.
       # Instead, will simply introduce a "primer" function
       # that gives access to every statement made so far
       # (question: should future statements be included?
       # tentatively assume YES: will simplify
       # discussion of creating modified copies of the
       # complete message).
       # For now, assume primer is a list of statements,
       # with each statement being a list in the same
       # form as "translate" functions expect.
       # This means that there is, for now, no
       # distinction between unary or binary,
       # and the "/" structure is expanded.
[hear] (intro primer);

       # this line is referred to later - change/move carefully
[hear] (equal (list-ref (primer) 0) (vector intro 1));

[hear] (equal (list-ref (primer) 1) (vector intro 2));

[hear] (equal (list-ref (primer) 2) (vector intro 3));

[hear] (assign idx (list-find (primer) (vector intro primer) (? x 0))
           (equal (list-ref (primer) (+ (idx) 1))
                  (vector equal
                      (vector list-ref (vector primer) 0)
                      (vector vector intro 1))));

       # Now, we could return to the MUD, simulate an agent A
       # transferring a copy of the primer to another agent B,
       # and then show B making a modified copy of that primer
       # and passing it back to A.
       # We could also show agents experimenting with the
       # primer in various ways.