Introducing type induction for DataSeries

Author: olekscode

DataFrame-Core.package/DataFrame.class/properties.json

@@ -4,7 +4,8 @@
 	"instvars" : [
 		"contents",
 		"rowNames",
-		"columnNames"
+		"columnNames",
+		"columnTypes"
 	],
 	"name" : "DataFrame",
 	"commentStamp" : "<historical>",

DataFrame-Core.package/DataSeries.class/class/fromSeries..st

@@ -6,6 +6,7 @@ fromSeries: aSeries
 
 	series keys: aSeries keys.
 	series name: aSeries name.
+	series type: aSeries type.
 
 	^ series
 

DataFrame-Core.package/DataSeries.class/class/newFrom..st

@@ -5,6 +5,9 @@ comparing
 	self name = otherSeries name
 		ifFalse: [ ^ false ].
 
+	self type = otherSeries type
+		ifFalse: [ ^ false ].
+		
 	self keys = otherSeries keys
 		ifFalse: [ ^ false ].
 

DataFrame-Core.package/DataSeries.class/instance/^equals.st

@@ -1,4 +1,16 @@
 accessing
 at: aNumber put: value
 
-	contents at: aNumber put: value.
+	contents at: aNumber put: value.
+	
+	self type isNil
+		"In case we fill the empty series with elements (e.g. collect)"
+		ifTrue: [ type := value class ]
+		
+		"In case we add an element to the existing series"
+		ifFalse: [ 
+			| inductor |
+			inductor := DataTypeInductor new.
+			type := inductor
+				leastCommonSuperclassOf: value class
+				and: self type. ].

DataFrame-Core.package/DataSeries.class/instance/at.put..st

@@ -4,4 +4,6 @@ fillWithValuesOf: anArray
 This method is private and should not be used in custom applications"
 
 	anArray doWithIndex: [ :each :i |
-		contents at: i put: each ].
+		contents at: i put: each ].
+	
+	self induceType.

DataFrame-Core.package/DataSeries.class/instance/fillWithValuesOf..st

@@ -0,0 +1,8 @@
+as yet unclassified
+induceType
+"Determines the least common superclass of all the values inside self and stores this class in type instance variable"
+
+	| inductor |
+	inductor := DataTypeInductor new.
+	
+	type := inductor typeOf: self.

DataFrame-Core.package/DataSeries.class/instance/induceType.st

@@ -0,0 +1 @@
+I induce the type of all the values inside DataSeries or DataFrame

DataFrame-Core.package/DataTypeInductor.class/README.md

@@ -0,0 +1,13 @@
+private
+leastCommonSuperclassOf: anArray
+"Determines the closest element of class hierarchy which is the common ancestor of all the classes in the array"
+
+	| commonSuperclass |
+	commonSuperclass := anArray first.
+	
+	2 to: anArray size do: [ :i |
+		commonSuperclass := self
+			leastCommonSuperclassOf: (anArray at: i)
+			and: commonSuperclass. ].
+	
+	^ commonSuperclass.

DataFrame-Core.package/DataTypeInductor.class/instance/leastCommonSuperclassOf..st

@@ -0,0 +1,21 @@
+private
+leastCommonSuperclassOf: firstClass and: secondClass
+"Determines the closest element of class hierarchy which is the common ancestor of two given classes"
+
+	| classA classB |
+	classA := firstClass.
+	classB := secondClass.
+	
+	[ classA = Object or: (classB = Object) ]
+		whileFalse: [ 
+			((classA inheritsFrom: classB) or:
+			(classA == classB)) 
+				ifTrue: [ ^ classB ].
+				
+			(classB inheritsFrom: classA)
+				ifTrue: [ ^ classA ].
+				
+			classA := classA superclass.
+			classB := classB superclass. ].
+	
+	^ Object.