		Search-engine friendly clone of the ACL2 documentation.

Omaps

Lookup

Value associated to a key in an omap.

Signature
(lookup key map) → val
Arguments: map — Guard (mapp map).

Definitions and Theorems

Function: lookup

(defun lookup (key map)
  (declare (xargs :guard (mapp map)))
  (declare (xargs :guard (assoc key map)))
  (let ((__function__ 'lookup))
    (declare (ignorable __function__))
    (cdr (assoc key map))))

Theorem: lookup-when-emptyp

(defthm lookup-when-emptyp
  (implies (emptyp map)
           (not (lookup key map)))
  :rule-classes (:rewrite :type-prescription))

Theorem: acl2-count-lookup-<-map

(defthm acl2-count-lookup-<-map
  (implies (not (emptyp map))
           (< (acl2-count (lookup key map))
              (acl2-count map))))

Theorem: lookup-of-tail-when-assoc-tail

(defthm lookup-of-tail-when-assoc-tail
  (implies (assoc key (tail map))
           (equal (lookup key (tail map))
                  (lookup key map))))