REBOL [ file: %r3-rehash.r title: "R3 Hash function" author: "Sunanda" date: 19-nov-2010 version: 0.0.2 purpose: {Provide a hash function (case sensitive map) for R3} library: [ level: 'beginner platform: 'all type: [tool function] domain: [math scientific financial] tested-under: [win] support: none license: 'BSD see-also: none history: [ 0.0.1 19-Nove-2010 {First release} ] ] ] rehash: context [ create: func ["Creates a new hash block" data [block!] /local hash ][ hash: make map! [] foreach [key item] data [ append hash reduce [__make-key key item] ] return hash ] retrieve: func ["Given a key, retrieves its data" hash [map!] key ][ return select hash __make-key key ] update: func ["Add/remove key and data (set data to none to remove)" hash [map!] key data ][ append hash reduce [__make-key key data] return true ] __make-key: func ["Internal function to convert key to binary" key ][ return either binary? key [key][to-binary form key] ] ] comment [ ;; example of usage ;; ====================== do %r3-rehash.r ;; create a hash with various datatypes as both key and data hash: rehash/create ["key1" 1111 #key2 "2222" 3x3 %data-3] rehash/retrieve hash #key2 ;; retrieve a value == "2222" rehash/update hash #key2 none ;; delete a [key value] pair == true rehash/retrieve hash #key2 ;; check it has gone == none ]