replace

Conformance: SketchyLISP Extension

Purpose: Replace data in forms. Replace for each occurence of old in form with new.

Arguments:
OLD - form to replace
NEW - form to insert
FORM - form to process

Implementation:

(define (replace old new form)
  (cond ((equal? form old) new)
    ((pair? form)
      (cons (replace old new (car form))
            (replace old new (cdr form))))
    (else form)))

Example:

(replace 'f 'g '(lambda (f x) (f x))) 
=> (lambda (g x) (g x))

See also:
substitute.