% (define next (lambda (y) (+ y 1)))
<define>
% (next 1)
2
% (next 2)
3
% (define fact (lambda (n) (if (= n 0) 1 (* n (fact (- n 1))))))
<define>
% (fact 3)
6
% (fact 5)
120
% (define foo (lambda (x) (lambda (y) (+ x y))))
<define>
% ((foo 3) 4)
7