Model Redesign: Added Reference Frames

Added Inverse Functions
UI Redesign
Cleaned Code

MathPad/MPTokenStream.m

@@ -9,7 +9,6 @@
 #import "MPTokenStream.h"
 
 @implementation MPTokenStream {
-    NSUInteger currentTokenIndex;
     NSUInteger eofLocation;
 }
 
@@ -32,37 +31,34 @@
     if (!self.isIgnoringWhitespaceTokens) {
         return;
     }
-    while (currentTokenIndex < self.tokens.count) {
-        MPToken *token = self.tokens[currentTokenIndex];
+    while (self.currentTokenIndex < self.tokens.count) {
+        MPToken *token = self.tokens[self.currentTokenIndex];
         if (token.tokenType != MPWhitespaceToken) {
             return;
         }
-        self.currentLocation = NSMaxRange(token.range);
-        ++currentTokenIndex;
+        ++self.currentTokenIndex;
     }
 }
 
 - (void)reset
 {
-    currentTokenIndex = 0;
-    self.currentLocation = 0;
+    self.currentTokenIndex = 0;
     [self skipWhitespaces];
 }
 
 - (BOOL)hasMoreTokens
 {
     [self skipWhitespaces];
-    return currentTokenIndex < self.tokens.count;
+    return self.currentTokenIndex < self.tokens.count;
 }
 
 - (MPToken *)nextToken
 {
     [self skipWhitespaces];
-    if (currentTokenIndex >= self.tokens.count) {
+    if (self.currentTokenIndex >= self.tokens.count) {
         return [[MPToken alloc] initEOFTokenAtLocation:eofLocation];
     } else {
-        MPToken *token = self.tokens[currentTokenIndex++];
-        self.currentLocation = NSMaxRange(token.range);
+        MPToken *token = self.tokens[self.currentTokenIndex++];
         return token;
     }
 }
@@ -70,15 +66,14 @@
 - (MPToken *)nextTokenOfType:(MPTokenType)type
 {
     [self skipWhitespaces];
-    if (currentTokenIndex >= self.tokens.count) {
+    if (self.currentTokenIndex >= self.tokens.count) {
         return nil;
     } else {
-        MPToken *token = self.tokens[currentTokenIndex];
+        MPToken *token = self.tokens[self.currentTokenIndex];
         if (token.tokenType != type) {
             return nil;
         }
-        ++currentTokenIndex;
-        self.currentLocation = NSMaxRange(token.range);
+        ++self.currentTokenIndex;
         return token;
     }
 }