PPT Slide

Cons stands for construct.

It produces a new dotted pair or “cons cell”.

(cons x y )

where

x is an S-expression

y is an S-expression

produces the dotted pair ( x • y ).

(cons ’a ’b) produces ( A • B )

which has the data structure

(cons x l )

where

x is an S-expression

l is a list

produces a new list with x as first element

followed by l .

(cons ’a (list ’b ’c) ) produces ( A B C )