-- adt IntList module IntList (List, nil, adjoin, isNull, ilHead, ilTail, equal) where -- representation data List = Nil | Cell Integer List deriving Show -- operations nil = Nil adjoin x l = Cell x l isNull Nil = True isNull (Cell _ _) = False ilHead Nil = error "no head" ilHead (Cell x _) = x ilTail Nil = error "no tail" ilTail (Cell _ l) = l equal Nil m = isNull m equal (Cell x l') m = not (isNull m) && x == ilHead m && equal l' (ilTail m)
'From Squeak3.6'! Object subclass: #Cell instanceVariableNames: 'head tail ' classVariableNames: '' poolDictionaries: '' category: 'Category-ProceduralDataAbstraction'! !Cell methodsFor: 'testing'! isNull ^ false! ! !Cell methodsFor: 'accessing'! head ^ head! ! !Cell methodsFor: 'accessing'! tail ^ tail! ! !Cell methodsFor: 'testing'! equal: m ^ m isNull not and: [self head = m head and: [self tail equal: m tail]]! ! !Cell methodsFor: 'private'! head: anInteger tail: tree head := anInteger. tail := tree! ! !Cell methodsFor: 'printing'! printOn: aStream aStream nextPutAll: self class printString, ' adjoin: ', head printString, ' with: '. tail isNull ifFalse: [aStream nextPut: $(]. aStream print: tail. tail isNull ifFalse: [aStream nextPut: $)]! ! !Cell class methodsFor: 'instance creation'! adjoin: anInteger with: tree ^ super new head: anInteger tail: tree; yourself! ! Object subclass: #Nil instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'Category-ProceduralDataAbstraction'! !Nil methodsFor: 'testing'! isNull ^ true! ! !Nil methodsFor: 'accessing'! head ^ self error: 'no head'! ! !Nil methodsFor: 'accessing'! tail ^ self error: 'no tail'! ! !Nil methodsFor: 'testing'! equal: m ^ m isNull! ! !Nil methodsFor: 'printing'! printOn: aStream aStream nextPutAll: self class name, ' new'! ! Object subclass: #IntList instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'Category-ProceduralDataAbstraction'! !IntList class methodsFor: 'example'! example "IntList example" | list list2 getBlockSource samples | getBlockSource := [ :block | | node method map startpc endpc start stop code index | node := block methodNode. method := block method. map := node sourceMap. startpc := block startpc. endpc := (method at: startpc-2)\\16-4*256 + (method at: startpc-1) + startpc - 1. stop := ((Dictionary newFrom: map) at: endpc) value last. index := map findLast: [ :each | each key < startpc]. index < 2 ifTrue: [start := 1] ifFalse: [ start := (map at: index) value last + 1. start > stop ifTrue: [start := 1]]. code := node sourceText copyFrom: start to: stop - 1. code allButFirst: (code indexOf: $[)]. samples := { [list := Cell adjoin: 1 with: (Cell adjoin: 2 with: Nil new).]. [list isNull.]. [list head.]. [list tail.]. [list tail head.]. [list2 := Nil new.]. [list2 isNull.]. [list equal: list2.]. [list equal: list copy.]}. World findATranscript: nil. samples do: [ :block | Transcript cr. Transcript show: (getBlockSource value: block). Transcript show: ' " ==> ', block value printString, ' "'] .[ "an output: " list := Cell adjoin: 1 with: (Cell adjoin: 2 with: Nil new). list isNull. " ==> false " list head. " ==> 1 " list tail. " ==> Cell adjoin: 2 with: Nil new " list tail head. " ==> 2 " list2 := Nil new. " ==> Nil new " list2 isNull. " ==> true " list equal: list2. " ==> false " list equal: list copy. " ==> true " ].! !
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