doc-src/Tutorial/Datatype/lookup
author paulson
Thu, 25 May 2000 15:15:22 +0200
changeset 8974 a76f80911eb9
parent 5851 15ce4c1c8313
permissions -rw-r--r--
sum_below moved here from Arith

consts   lookup :: ('a,'v)trie => 'a list => 'v option
primrec "lookup t [] = value t"
        "lookup t (a#as) = (case assoc (alist t) a of
                              None => None
                            | Some at => lookup at as)"