I am starting to add a basic table view to Morphic.

package-sources/Morphic.Core/DataSource.sysmel

@@ -0,0 +1,7 @@
+public abstract class DataSource definition: {
+    public abstract method numberOfElements => Size
+        := self subclassResponsibility.
+
+    public abstract method elementAtRow: (rowIndex: Size) ::=> AnyValue
+        := self subclassResponsibility.
+}.

package-sources/Morphic.Core/ListViewMorph.sysmel

@@ -0,0 +1,20 @@
+public class ListViewMorph superclass: TableViewMorph; definition: {
+    protected field listDataSource => SimpleListDataSource.
+
+    public override method initialize => Void := {
+        super initialize.
+        listDataSource := SimpleListDataSource new.
+        self dataSource: listDataSource.
+    }.
+
+    public method removeAll => Void := {
+        listDataSource removeAll.
+        self changed.
+    }.
+
+    public method addItem: item ::=> Size := {
+        let index := listDataSource addItem: item.
+        self changed.
+        index
+    }.
+}.

package-sources/Morphic.Core/Morph.sysmel

@@ -73,11 +73,14 @@ public class Morph superclass: MorphLayoutElement; definition: {
         builder translate: localSceneGraph -- childrenSceneGraph with: self position
     }.
 
+    public virtual method validSubmorphs => Array
+        := submorphs.
+
     public virtual method buildChildrenSceneGraphWith: (builder: FormSGBuilder) ::=> FormSGNode := {
-        submorphs isEmpty ifTrue: {return: builder null}.
+        self validSubmorphs isEmpty ifTrue: {return: builder null}.
 
-        let nodeSceneGraphList := Array new: submorphs size.
-        submorphs doWithIndex: {:(Morph)childMorph :(Size)childMorphIndex :: Void |
+        let nodeSceneGraphList := Array new: self validSubmorphs size.
+        self validSubmorphs doWithIndex: {:(Morph)childMorph :(Size)childMorphIndex :: Void |
             nodeSceneGraphList at: childMorphIndex put: (childMorph buildFullSceneGraphWith: builder)
         }.
 
@@ -135,6 +138,18 @@ public class Morph superclass: MorphLayoutElement; definition: {
         submorphs := #().
     }.
 
+    public method replaceAllMorphsWith: (newMorphs: Collection) ::=> Void := {
+        self removeAllMorphs.
+
+        let newSubmorphs := Array new: newMorphs size.
+        newMorphs doWithIndex: {:(Morph)each :(Size)index :: Void |
+            each owner: self.
+            newSubmorphs at: index put: each.
+        }.
+
+        submorphs := newSubmorphs.
+    }.
+
     public method removeMorph: (morph: Morph) ::=> Void := {
         self assert: morph owner == self.
         submorphs := submorphs copyWithout: morph
@@ -146,7 +161,7 @@ public class Morph superclass: MorphLayoutElement; definition: {
 
     public virtual method processMouseButtonPressedEvent: (event: MouseButtonPressedEvent) ::=> Void := {
         event withLocalTranslation: self position do: {:: Void |
-            submorphs reverseDo: {:(Morph)each :: Void |
+            self validSubmorphs reverseDo: {:(Morph)each :: Void |
                 (each bounds includesPoint: event position) ifTrue: {
                     each processMouseButtonPressedEvent: event
                 }
@@ -164,7 +179,7 @@ public class Morph superclass: MorphLayoutElement; definition: {
 
     public virtual method processMouseButtonReleasedEvent: (event: MouseButtonReleasedEvent) ::=> Void := {
         event withLocalTranslation: self position do: {:: Void |
-            submorphs reverseDo: {:(Morph)each :: Void |
+            self validSubmorphs reverseDo: {:(Morph)each :: Void |
                 (each bounds includesPoint: event position) ifTrue: {
                     each processMouseButtonReleasedEvent: event
                 }
@@ -182,7 +197,7 @@ public class Morph superclass: MorphLayoutElement; definition: {
 
     public virtual method processMouseMoveEvent: (event: MouseMoveEvent) ::=> Void := {
         event withLocalTranslation: self position do: {:: Void |
-            submorphs reverseDo: {:(Morph)each :: Void |
+            self validSubmorphs reverseDo: {:(Morph)each :: Void |
                 (each bounds includesPoint: event position) ifTrue: {
                     each processMouseMoveEvent: event
                 }

package-sources/Morphic.Core/MorphBoxLayout.sysmel

@@ -6,17 +6,17 @@ public abstract class MorphBoxLayout superclass: MorphLayout; definition: {
         elements := OrderedCollection new.
     }.
 
-    public method add: (target: MorphLayoutElement) proportion: (proportion: UInt32) borderWidth: (borderWidth: Float32) ::=> Void := {
+    public method add: (target: MorphLayoutElement) proportion: (proportion: Float32) borderWidth: (borderWidth: Float32) ::=> Void := {
         elements add: (MorphBoxLayoutElement new
             target: target;
             proportion: proportion;
             borderWidth: borderWidth;
             yourself)
     }.
 
-    public method add: (target: MorphLayoutElement) proportion: (proportion: UInt32) ::=> Void
+    public method add: (target: MorphLayoutElement) proportion: (proportion: Float32) ::=> Void
         := self add: target proportion: proportion borderWidth: 0f32.
 
     public method add: (element: MorphLayoutElement) ::=> Void
-        := self add: element proportion: 0u32.
+        := self add: element proportion: 0f32.
 }.

package-sources/Morphic.Core/MorphBoxLayoutElement.sysmel

@@ -1,13 +1,13 @@
 public class MorphBoxLayoutElement superclass: MorphLayoutElement; definition: {
     public field target => MorphLayoutElement.
-    public field proportion => UInt32.
+    public field proportion => Float32.
     public field borderWidth => Float32.
 
     public override method bounds => RectangleF32
         := target bounds expandBy: borderWidth@borderWidth.
 
     public override method bounds: (newBounds: RectangleF32) ::=> Void := {
-        proportion = 0u32 ifTrue: {
+        proportion = 0f32 ifTrue: {
             target position: newBounds min + (borderWidth@borderWidth)
         } ifFalse: {
             target bounds: (newBounds insetBy: borderWidth@borderWidth)

package-sources/Morphic.Core/MorphHorizontalBoxLayout.sysmel

@@ -1,12 +1,12 @@
 public class MorphHorizontalBoxLayout superclass: MorphBoxLayout; definition: {
     public override method bounds: (newBounds: RectangleF32) ::=> Void := {
         let usedWidth mutable := 0f32.
-        let totalProportion mutable := 0u32.
+        let totalProportion mutable := 0f32.
 
         ## Compute the used height and the total proportion.
         elements do: {:(MorphBoxLayoutElement)element :: Void |
             let proportion := element proportion.
-            proportion = 0u32 ifTrue: {
+            proportion = 0f32 ifTrue: {
                 usedWidth := usedWidth + element bounds width
             } ifFalse: {
                 totalProportion := totalProportion + proportion
@@ -22,9 +22,9 @@ public class MorphHorizontalBoxLayout superclass: MorphBoxLayout; definition: {
         let destY := newBounds min y.
         elements do: {:(MorphBoxLayoutElement)element :: Void |
             let proportion := element proportion.
-            let elementWidth := proportion = 0u32
+            let elementWidth := proportion = 0f32
                 ifTrue: (element bounds width)
-                ifFalse: (availableWidth * proportion asFloat32 / totalProportion asFloat32).
+                ifFalse: (availableWidth * proportion / totalProportion).
 
             let elementBounds := destX@destY extent: elementWidth@availableHeight.
             element bounds: elementBounds.

package-sources/Morphic.Core/MorphVerticalBoxLayout.sysmel

@@ -1,12 +1,12 @@
 public class MorphVerticalBoxLayout superclass: MorphBoxLayout; definition: {
     public override method bounds: (newBounds: RectangleF32) ::=> Void := {
         let usedHeight mutable := 0f32.
-        let totalProportion mutable := 0u32.
+        let totalProportion mutable := 0f32.
 
         ## Compute the used height and the total proportion.
         elements do: {:(MorphBoxLayoutElement)element :: Void |
             let proportion := element proportion.
-            proportion = 0u32 ifTrue: {
+            proportion = 0f32 ifTrue: {
                 usedHeight := usedHeight + element bounds height
             } ifFalse: {
                 totalProportion := totalProportion + proportion
@@ -21,9 +21,9 @@ public class MorphVerticalBoxLayout superclass: MorphBoxLayout; definition: {
         let destY mutable := newBounds min y.
         elements do: {:(MorphBoxLayoutElement)element :: Void |
             let proportion := element proportion.
-            let elementHeight := proportion = 0u32
+            let elementHeight := proportion = 0f32
                 ifTrue: (element bounds height)
-                ifFalse: (availableHeight * proportion asFloat32 / totalProportion asFloat32).
+                ifFalse: (availableHeight * proportion / totalProportion).
 
             let elementBounds := destX@destY extent: availableWidth@elementHeight.
             element bounds: elementBounds.

package-sources/Morphic.Core/SimpleListDataSource.sysmel

@@ -0,0 +1,26 @@
+public class SimpleListDataSource superclass: DataSource; definition: {
+    public field items => OrderedCollection.
+
+    public override method initialize => Void := {
+        super initialize.
+        items := OrderedCollection new.
+    }.
+
+    public override method numberOfElements => Size
+        := items size.
+
+    public override method elementAtRow: (rowIndex: Size) ::=> AnyValue
+        := rowIndex < items size
+            ifTrue: (items at: rowIndex)
+            ifFalse: nil.
+
+    public method removeAll => Void := {
+        items removeAll
+    }.
+
+    public method addItem: item ::=> Size := {
+        let index := items size.
+        items add: item.
+        index
+    }.
+}.

package-sources/Morphic.Core/StringTableViewColumn.sysmel

@@ -0,0 +1,17 @@
+public class StringTableViewColumn superclass: TableViewColumn; definition: {
+    let DisplayBlockType := (AnyValue) => String.
+
+    public field display => DisplayBlockType.
+
+    public override method initialize => Void := {
+        super initialize.
+        display := {:element :: String | element asString }.
+    }.
+
+    public override method createCellMorphForElement: element ::=> Morph
+        := display(element) asMorph.
+
+    public override method updateCellMorph: (morph: Morph) withElement: element ::=> Void := {
+        (morph downCastTo: StringMorph) contents: display(element)
+    }.
+}.

package-sources/Morphic.Core/TableRowSelection.sysmel

@@ -0,0 +1,16 @@
+public class TableRowSelection definition: {
+    public field selectedIndices => Array.
+
+    __Meta__ definition: {
+        public method with: (index: Size) ::=> self
+            := self new selectedIndices: (Array with: index); yourself
+    }.
+
+    public override method initialize => Void := {
+        super initialize.
+        selectedIndices := #().
+    }.
+
+    public method includesRowIndex: (index: Size) ::=> Boolean
+        := selectedIndices includes: index.
+}.

package-sources/Morphic.Core/TableViewColumn.sysmel

@@ -0,0 +1,14 @@
+public abstract class TableViewColumn definition: {
+    public field name => String.
+    public field width => Float32.
+
+    public virtual method minimalCellExtent ::=> Float32x2
+        := 0f32 @ FontFace default height.
+
+    public virtual method createCellMorphForElement: element ::=> Morph
+        := Morph new.
+
+    public virtual method updateCellMorph: (morph: Morph) withElement: element ::=> Void := {
+        ## By default do nothing.
+    }.
+}.

package-sources/Morphic.Core/TableViewContentMorph.sysmel

@@ -0,0 +1,122 @@
+TableViewContentMorph definition: {
+    protected field visibleRows => Array.
+
+    public override method initialize => Void := {
+        super initialize.
+        visibleRows := #().
+    }.
+
+    public method tableViewMorph => TableViewMorph
+        := owner downCastTo: TableViewMorph.
+
+    public method dataSource => DataSource
+        := self tableViewMorph dataSource.
+
+    public method columns => OrderedCollection
+        := self tableViewMorph columns.
+
+    public method rowHeight => Float32
+        := self tableViewMorph rowHeight.
+
+    public override method defaultColor => Color
+        := Color transparent.
+
+    public override method validSubmorphs => Array := {
+        self ensureThatVisibleRowsExists.
+        super validSubmorphs
+    }.
+
+    public method updateContent => Void := {
+        self ensureThatVisibleRowsExists.
+        visibleRows do: {:(TableViewRowMorph)eachRow :: Void |
+            eachRow updateContent
+        }
+    }.
+
+    public override method updateLayout => Void := {
+        let rowHeight := self rowHeight.
+        let rowExtent := self extent x @ rowHeight.
+
+        visibleRows do: {:(TableViewRowMorph)eachRow :: Void |
+            let rowPosition := 0f32 @ (eachRow rowIndex asFloat32 * rowHeight).
+            eachRow bounds: (rowPosition extent: rowExtent)
+        }.
+    }.
+
+    public method computeVisibleRowRangeFrom: (firstVisibleRow: Size ref) to: (lastVisibleRow: Size ref) ::=> Void := {
+        let visibleBounds := self localBounds.
+        let rowHeight := self rowHeight.
+        let dataSource := self dataSource.
+        let elementCount := dataSource ifNil: 0sz ifNotNil: dataSource numberOfElements.
+        let maxRowIndex := elementCount > 0sz ifTrue: elementCount - 1sz ifFalse: 0sz.
+
+        firstVisibleRow := ((visibleBounds min y / rowHeight) floor max: 0f32) asSize min: maxRowIndex.
+        lastVisibleRow := ((visibleBounds max y / rowHeight) ceiling max: 0f32) asSize min: maxRowIndex.
+    }.
+
+    public method ensureThatVisibleRowsExists => Void := {
+        let dataSource := self dataSource.
+        dataSource isNil || (dataSource numberOfElements = 0sz) ifTrue: {
+            self removeAllMorphs.
+            visibleRows := #().
+            return: void
+        }.
+
+        let firstVisibleRowIndex mutable := 0sz.
+        let lastVisibleRowIndex mutable := 0sz.
+        self computeVisibleRowRangeFrom: firstVisibleRowIndex to: lastVisibleRowIndex.
+
+        visibleRows isNotEmpty &&
+        (firstVisibleRowIndex = visibleRows first rowIndex) && 
+        (lastVisibleRowIndex = visibleRows last rowIndex) ifTrue: {
+            return: void
+        }.
+
+        let overlappingRows := visibleRows select: {:(TableViewRowMorph)eachRowMorph :: Boolean |
+            (firstVisibleRowIndex <= eachRowMorph rowIndex) && (eachRowMorph rowIndex <= lastVisibleRowIndex)
+        }.
+
+        let previousEndIndex := overlappingRows isEmpty
+            ifTrue: (firstVisibleRowIndex)
+            ifFalse: (overlappingRows first rowIndex).
+        let nextStartIndex := overlappingRows isEmpty
+            ifTrue: (firstVisibleRowIndex)
+            ifFalse: (overlappingRows last rowIndex + 1sz).
+
+        let newVisibleRows := OrderedCollection new.
+
+        {
+            let i mutable := firstVisibleRowIndex.
+            while: (i < previousEndIndex) do: {
+                let rowMorph := TableViewRowMorph new.
+                self addMorph: rowMorph.
+
+                newVisibleRows add: (rowMorph
+                    rowIndex: i;
+                    createCells;
+                    updateContent;
+                    yourself)
+            } continueWith: (i := i + 1sz).
+        }.
+
+        newVisibleRows addAll: overlappingRows.
+
+        {
+            let i mutable := nextStartIndex.
+            while: (i <= lastVisibleRowIndex) do: {
+                let rowMorph := TableViewRowMorph new.
+                self addMorph: rowMorph.
+
+                newVisibleRows add: (rowMorph
+                    rowIndex: i;
+                    createCells;
+                    updateContent;
+                    yourself)
+            } continueWith: (i := i + 1sz).
+        }.
+
+        visibleRows := newVisibleRows asArray.
+        self replaceAllMorphsWith: visibleRows.
+        self updateLayout.
+    }.
+}.

package-sources/Morphic.Core/TableViewHeaderMorph.sysmel

@@ -0,0 +1,3 @@
+TableViewHeaderMorph definition: {
+
+}.