Name

prog

Usage

special-form

Syntax

(prog (binding*) form*)

Description

prog allows tail recursion with reprog. The binding defines the parameters and initial arguments of the recursion. The reprog form should be in a tail position. If reprog is not used, prog is similar to Common Lisp's prog.

The code of a prog is contained in a block prog, Therefore leave prog returns from the directly enclosing prog. The special form reprog is implemented with redo prog.

make-html > (defun fac (n)
                (prog ((n n) (a 1))
                    (if (plus? n)
                          (reprog (dec n) (* a n))
                        a)))
it: fac
make-html > (fac 30)
it: 265252859812191058636308480000000

See also

reprog