Add solución con ifs. pasa tests ej a

15-Stack/Stack-Exercise.st

@@ -139,24 +139,112 @@ test10CanNotTopWhenThereAreNoObjectsInTheStack
 
 !classDefinition: #SentenceFinderByPrefixTest category: #'Stack-Exercise'!
 TestCase subclass: #SentenceFinderByPrefixTest
-	instanceVariableNames: ''
+	instanceVariableNames: 'stack results'
 	classVariableNames: ''
 	poolDictionaries: ''
 	category: 'Stack-Exercise'!
 
+!SentenceFinderByPrefixTest methodsFor: 'setUp/tearDown' stamp: 'JPC 5/14/2020 23:56:31'!
+setup
+	
+	stack _ OOStack new.
+	stack push: 'winter is coming'.
+	stack push: 'winning is everything'.
+	stack push: 'The winds of Winter'.
+	stack push: 'Winter is here'.! !
+
+
+!SentenceFinderByPrefixTest methodsFor: 'testing' stamp: 'JPC 5/15/2020 00:15:55'!
+test01BuscarAlgoQueNoExisteDevuelveSetVacio
+	
+	results _ SentenceFinderByPrefix find: 'foo' inOOStack: stack.
+
+	self assert: results equals: Set new.! !
+
+
+!classDefinition: #Cons category: #'Stack-Exercise'!
+Object subclass: #Cons
+	instanceVariableNames: 'head tail object elements_CHANGE_ME'
+	classVariableNames: ''
+	poolDictionaries: ''
+	category: 'Stack-Exercise'!
+
+!Cons methodsFor: 'initialization' stamp: 'JPC 5/14/2020 23:15:24'!
+initializeWithHead: anObject tail: aCons 
+	head _ anObject.
+	tail _ aCons.! !
+
+
+!Cons methodsFor: 'accessing' stamp: 'JPC 5/14/2020 23:17:17'!
+head
+	^head! !
+
+!Cons methodsFor: 'accessing' stamp: 'JPC 5/14/2020 23:17:37'!
+tail
+	^tail! !
+
+
+!Cons methodsFor: 'as yet unclassified' stamp: 'JPC 5/14/2020 23:26:12'!
+size
+  ^ tail ifNil: [1] ifNotNil: [1 + tail size].! !
+
+"-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- "!
+
+!classDefinition: 'Cons class' category: #'Stack-Exercise'!
+Cons class
+	instanceVariableNames: 'object elements_CHANGE_ME'!
+
+!Cons class methodsFor: 'instance creation' stamp: 'JPC 5/14/2020 23:13:56'!
+initializeWithHead: aString tail: anUndefinedObject 
+	"DO NOT FORGET TO RENAME COLLABORATORS AND REMOVE THIS COMMENT!!!!"
+	self shouldBeImplemented.
+	^self new initializeInitializeWithHead: aString tail: anUndefinedObject ! !
+
 
 !classDefinition: #OOStack category: #'Stack-Exercise'!
 Object subclass: #OOStack
-	instanceVariableNames: ''
+	instanceVariableNames: 'elements'
 	classVariableNames: ''
 	poolDictionaries: ''
 	category: 'Stack-Exercise'!
 
+!OOStack methodsFor: 'testing' stamp: 'JPC 5/14/2020 21:40:59'!
+isEmpty
+	^ elements isNil.! !
+
+
+!OOStack methodsFor: 'insertion' stamp: 'JPC 5/14/2020 23:14:36'!
+push: anObject 
+	elements _ Cons new initializeWithHead: anObject tail: elements.! !
+
+
+!OOStack methodsFor: 'FIXME' stamp: 'JPC 5/14/2020 23:34:29'!
+pop
+	| topObject |
+	
+	elements ifNil: [^ self error: self class stackEmptyErrorDescription].
+	
+	topObject _ elements head.
+	elements _ elements tail.
+	^ topObject.! !
+
+!OOStack methodsFor: 'FIXME' stamp: 'JPC 5/14/2020 23:22:59'!
+size
+	^ elements size.! !
+
+
+!OOStack methodsFor: 'accessing' stamp: 'JPC 5/14/2020 23:35:28'!
+top
+	
+	elements ifNil: [^ self error: self class stackEmptyErrorDescription].
+
+	^ elements head.! !
+
 "-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- "!
 
 !classDefinition: 'OOStack class' category: #'Stack-Exercise'!
 OOStack class
-	instanceVariableNames: ''!
+	instanceVariableNames: 'elements'!
 
 !OOStack class methodsFor: 'error descriptions' stamp: 'HernanWilkinson 5/7/2012 11:51'!
 stackEmptyErrorDescription