Improved Model

Added Keyboard Selection Support
Added Mouse Selection Support
Added Keyboard Editing Support
Corrected Some Bugs
Abstracted the Layout System further
Added Functions Button (test)

MathPad/NSIndexPath+MPAdditions.m

@@ -10,6 +10,16 @@
 
 @implementation NSIndexPath (MPAdditions)
 
+- (NSUInteger)lastIndex
+{
+    return [self indexAtPosition:self.length-1];
+}
+
+- (NSIndexPath *)indexPathByReplacingLastIndexWithIndex:(NSUInteger)index
+{
+    return [[self indexPathByRemovingLastIndex] indexPathByAddingIndex:index];
+}
+
 - (NSIndexPath *)indexPathByRemovingFirstIndex
 {
     if (self.length <= 1) {
@@ -34,4 +44,18 @@
     return [[NSIndexPath alloc] initWithIndexes:newIndexes length:self.length+1];
 }
 
+- (NSIndexPath *)indexPathByIncrementingLastIndex
+{
+    NSUInteger lastIndex = [self lastIndex];
+    lastIndex++;
+    return [[self indexPathByRemovingLastIndex] indexPathByAddingIndex:lastIndex];
+}
+
+- (NSIndexPath *)indexPathByDecrementingLastIndex
+{
+    NSUInteger lastIndex = [self lastIndex];
+    lastIndex--;
+    return [[self indexPathByRemovingLastIndex] indexPathByAddingIndex:lastIndex];
+}
+
 @end