Started to Implement Evaluation

Corrected Some Errors
Cleaned Code

MathPad/Base.lproj/MPDocument.xib

@@ -22,15 +22,28 @@
                 <autoresizingMask key="autoresizingMask"/>
                 <subviews>
                     <customView translatesAutoresizingMaskIntoConstraints="NO" id="lcd-Ip-jjR" customClass="MPExpressionView">
-                        <rect key="frame" x="20" y="20" width="467" height="211"/>
+                        <rect key="frame" x="20" y="61" width="467" height="170"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                     </customView>
+                    <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="lvU-8o-qPV">
+                        <rect key="frame" x="207" y="13" width="93" height="32"/>
+                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
+                        <buttonCell key="cell" type="push" title="Evaluate" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="Zda-mn-Rjr">
+                            <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
+                            <font key="font" metaFont="system"/>
+                        </buttonCell>
+                        <connections>
+                            <action selector="evaluateExpressiom:" target="-2" id="jUp-32-wwK"/>
+                        </connections>
+                    </button>
                 </subviews>
                 <constraints>
-                    <constraint firstItem="lcd-Ip-jjR" firstAttribute="leading" secondItem="gIp-Ho-8D9" secondAttribute="leading" constant="20" symbolic="YES" id="8Li-0i-x3o"/>
+                    <constraint firstAttribute="bottom" secondItem="lvU-8o-qPV" secondAttribute="bottom" constant="20" symbolic="YES" id="5ws-Hh-dXO"/>
-                    <constraint firstItem="lcd-Ip-jjR" firstAttribute="top" secondItem="gIp-Ho-8D9" secondAttribute="top" constant="20" symbolic="YES" id="MPQ-lK-4d0"/>
+                    <constraint firstItem="lvU-8o-qPV" firstAttribute="top" secondItem="lcd-Ip-jjR" secondAttribute="bottom" constant="20" symbolic="YES" id="CEh-81-Hu6"/>
-                    <constraint firstAttribute="bottom" secondItem="lcd-Ip-jjR" secondAttribute="bottom" constant="20" symbolic="YES" id="hi3-fp-zJn"/>
+                    <constraint firstItem="lcd-Ip-jjR" firstAttribute="top" secondItem="gIp-Ho-8D9" secondAttribute="top" constant="20" symbolic="YES" id="Raj-xq-imM"/>
-                    <constraint firstAttribute="trailing" secondItem="lcd-Ip-jjR" secondAttribute="trailing" constant="20" symbolic="YES" id="xiK-zs-2rs"/>
+                    <constraint firstAttribute="trailing" secondItem="lcd-Ip-jjR" secondAttribute="trailing" constant="20" symbolic="YES" id="Xh2-Qb-urL"/>
+                    <constraint firstItem="lcd-Ip-jjR" firstAttribute="centerX" secondItem="lvU-8o-qPV" secondAttribute="centerX" id="pq6-dU-P1M"/>
+                    <constraint firstItem="lcd-Ip-jjR" firstAttribute="leading" secondItem="gIp-Ho-8D9" secondAttribute="leading" constant="20" symbolic="YES" id="wPr-ZO-8KR"/>
                 </constraints>
             </view>
             <connections>

MathPad/MPDocument.h

@@ -10,9 +10,8 @@
 
 @interface MPDocument : NSDocument
 
-@property (weak) IBOutlet MPExpressionView *termExpressionView;
 @property (weak) IBOutlet MPExpressionView *resultExpressionView;
 
-- (IBAction)changeExpression:(id)sender;
+- (IBAction)evaluateExpressiom:(id)sender;
 
 @end

MathPad/MPDocument.m

@@ -7,7 +7,6 @@
 //
 
 #import "MPDocument.h"
-#import "MPModel.h"
 #import "MPView.h"
 
 @implementation MPDocument
@@ -59,8 +58,12 @@
 }
 
 #pragma mark Actions
-- (IBAction)changeExpression:(id)sender {
+- (IBAction)evaluateExpressiom:(id)sender {
-    [self.resultExpressionView.expressionStorage insertElement:@"abc" atLocation:6];
+    NSError *error;
+    NSLog(@"Result: %f", [self.resultExpressionView.expressionStorage evaluateExpression:&error]);
+    if (error) {
+        NSLog(@"Error: %@", error);
+    }
 }
 
 @end

MathPad/MPExpression.h

@@ -9,7 +9,7 @@
 @import Foundation;
 #import "NSString+MPExpressionElement.h"
 
-@class MPExpression, MPFunction, MPRangePath;
+@class MPExpression, MPFunction, MPRangePath, MPExpressionEvaluator;
 @protocol MPExpressionElement;
 
 /*!
@@ -269,8 +269,26 @@
 - (void)replaceSymbolsInRange:(NSRange)range
                  withElements:(NSArray *)elements;
 
-#warning Evaluating must possibly return error
+
-- (double)doubleValue; // Evaluates Expression
+/*!
+ @method     elements
+ @brief      Returns an array of all elements in the receiver.
+ 
+ @discussion The elements in the returned array are not copied before they are
+ returned.
+ 
+ @return     An array of all elements from the receiver.
+ */
+- (NSArray *)elements;
+
+
+#pragma mark Evaluating Expressions
+
+- (double)evaluateExpression:(NSError *__autoreleasing *)error;
+
+
+// TODO: Private?
+@property (readonly, nonatomic, strong) MPExpressionEvaluator *evaluator;
 
 #pragma mark Notifications
 // All notification methods should create a new rangePath with the receiver's index added to the beginning of the path and then ascend the message to it's parent
@@ -312,7 +330,7 @@
     @return     @c YES if @c anExpression is equal to the receiver, @c NO
                 otherwise.
  */
-- (BOOL)isEqualToExpression:(MPExpression *)anExpression;
+// - (BOOL)isEqualToExpression:(MPExpression *)anExpression;
 
 - (NSString *)description;
 - (NSUInteger)hash;
@@ -534,21 +552,6 @@
 - (void)deleteElementsInRange:(NSRange)range;
 
 
-#pragma mark Querying Expressions
-
-
-/*!
-    @method     elements
-    @brief      Returns an array of all elements in the receiver.
- 
-    @discussion The elements in the returned array are not copied before they are
-                returned.
- 
-    @return     An array of all elements from the receiver.
- */
-- (NSArray *)elements;
-
-
 /*!
     @method     mutableElements
     @brief      Returns a proxy mutable array object that responds to all methods
@@ -564,3 +567,4 @@
 // - (NSMutableArray *)mutableElements;
 
 @end
+

MathPad/MPExpression.m

@@ -6,6 +6,8 @@
 //  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
 //
 
+// TODO: Reorganise header/implementation order. Drop the primitive/not primitive Approach
+
 #import "MPExpression.h"
 #import "MPFunction.h"
 #import "MPRangePath.h"
@@ -13,8 +15,11 @@
 #import "NSIndexPath+MPAdditions.h"
 #import "MPException.h"
 
-@interface MPExpression ()
+#import "MPExpressionEvaluator.h"
-@property (readonly, nonatomic, strong) NSMutableArray *elements;
+
+@interface MPExpression () {
+    NSMutableArray *__strong _elements;
+}
 @end
 
 @interface MPExpression (MPExpressionPrivate)
@@ -64,8 +69,8 @@
         NSString *splitElement = (NSString *)self.elements[splitElementIndex];
         NSString *leftPart = [splitElement substringToIndex:splitOffset];
         NSString *rightPart = [splitElement substringFromIndex:splitOffset];
-        [self.elements replaceObjectsInRange:NSMakeRange(splitElementIndex, 1)
+        [_elements replaceObjectsInRange:NSMakeRange(splitElementIndex, 1)
-                        withObjectsFromArray:@[leftPart, rightPart]];
+                    withObjectsFromArray:@[leftPart, rightPart]];
         ++splitElementIndex;
     }
     *insertionIndex = splitElementIndex;
@@ -81,8 +86,6 @@
     NSUInteger _replacementLength;
 }
 
-@synthesize elements = _elements;
-
 #pragma mark Creation Methods
 - (instancetype)init
 {
@@ -114,14 +117,14 @@
         id<MPExpressionElement> current = self.elements[index];
         if ([current isString]) {
             if (current.length == 0) {
-                [self.elements removeObjectAtIndex:index];
+                [_elements removeObjectAtIndex:index];
                 if (index >= _editedRange.location && index < NSMaxRange(_editedRange)) {
                     --_replacementLength;
                 }
                 --index;
             } else if ([next isString]) {
                 NSString *new = [NSString stringWithFormat:@"%@%@", current, next];
-                [self.elements replaceObjectsInRange:NSMakeRange(index, 2)
+                [_elements replaceObjectsInRange:NSMakeRange(index, 2)
                                 withObjectsFromArray:@[new]];
                 NSUInteger maxReplacementIndex = _editedRange.location + _replacementLength;
                 if (index == _editedRange.location - 1) {
@@ -244,7 +247,7 @@
     // Perform the replacement
     NSMutableArray *newElements = [[NSMutableArray alloc] initWithArray:elements
                                                               copyItems:YES];
-    [self.elements replaceObjectsInRange:NSMakeRange(startIndex, endIndex-startIndex)
+    [_elements replaceObjectsInRange:NSMakeRange(startIndex, endIndex-startIndex)
                     withObjectsFromArray:newElements];
     
     _cachedLength = 0;
@@ -260,11 +263,23 @@
                      replacementLength:_replacementLength];
 }
 
-
+- (NSArray *)elements
-- (double)doubleValue
 {
-#warning Unimplemented Method
+    return _elements;
-    return 0;
+}
+
+- (double)evaluateExpression:(NSError *__autoreleasing *)error
+{
+    return [self.evaluator evaluateWithError:error];
+}
+
+@synthesize evaluator = _evaluator;
+- (MPExpressionEvaluator *)evaluator
+{
+    if (!_evaluator) {
+        _evaluator = [[MPExpressionEvaluator alloc] initWithExpression:self];
+    }
+    return _evaluator;
 }
 
 #pragma mark Notifications
@@ -272,8 +287,7 @@
                    replacementLength:(NSUInteger)replacementLength
 {
     NSUInteger selfIndex = [self.parent indexOfChild:self];
-    MPRangePath *newPath = rangePath.copy;
+    MPRangePath *newPath = MPMakeRangePath([rangePath.location indexPathByPreceedingIndex:selfIndex], rangePath.length);
-    newPath.location = [newPath.location indexPathByPreceedingIndex:selfIndex];
     [self.parent didChangeElementsInRangePath:newPath
                             replacementLength:replacementLength];
 }

MathPad/MPExpressionLayout.m

@@ -16,7 +16,6 @@
 @interface MPExpressionLayout (MPLineGeneration)
 
 - (CTLineRef)lineForElementAtIndex:(NSUInteger)index;
-- (CTLineRef)createLineForString:(NSString *)aString;
 
 @end
 
@@ -36,16 +35,6 @@
     return (__bridge CTLineRef)lineObject;
 }
 
-- (CTLineRef)createLineForString:(NSString *)aString
-{
-    NSAttributedString *text = [[NSAttributedString alloc] initWithString:aString
-                                                               attributes:@{NSFontAttributeName: self.font}];
-    CFAttributedStringRef attributedString = CFBridgingRetain(text);
-    CTLineRef line = CTLineCreateWithAttributedString(attributedString);
-    CFRelease(attributedString); // TODO: Is this release appropriate?
-    return line;
-}
-
 @end
 
 @implementation MPExpressionLayout

MathPad/MPExpressionView.m

@@ -51,7 +51,7 @@
 {
     NSRect expressionBounds = [self.expressionStorage.rootLayout bounds];
     CGFloat y = (self.bounds.size.height - expressionBounds.size.height) / 2 + fabs(expressionBounds.origin.y);
-    return NSMakePoint(self.bounds.origin.x, self.bounds.origin.y + y);
+    return NSMakePoint(0, y);
 }
 
 @end
@@ -124,15 +124,19 @@
 
 - (void)initializeExpressionView
 {
+    // Setup the Expression Storage
     MPExpressionStorage *expressionStorage = [[MPExpressionStorage alloc] initWithElements:@[@"12345", [[MPSumFunction alloc] init], [[MPSumFunction alloc] init]]];
     expressionStorage.expressionView = self;
     _expressionStorage = expressionStorage;
-    NSRect frame = NSMakeRect(10, 10, 500, 500);
+    
-    NSButton *button = [[NSButton alloc] initWithFrame:frame];
+    // Setup the Functions Button
+    NSButton *button = [[NSButton alloc] initWithFrame:NSZeroRect];
     button.buttonType = NSSwitchButton;
     [button setTitle:@"Functions"];
     self.functionsButton = button;
     [self addSubview:self.functionsButton];
+    
+    // Setup Selection
     self.selection = [[MPRangePath alloc] initWithRange:NSMakeRange(0, 0)];
     self.caretBlinkRate = 1.0;
     [self restartCaretTimer];
@@ -202,7 +206,9 @@
 - (void)keyDown:(NSEvent *)theEvent
 {
     NSString *characters = theEvent.characters;
-    if (characters.length == 1 && [characters stringByTrimmingCharactersInSet:[NSCharacterSet decimalDigitCharacterSet]].length == 0) {
+    NSMutableCharacterSet *allowedCharacters = [NSMutableCharacterSet alphanumericCharacterSet];
+    [allowedCharacters addCharactersInString:@"+-*/= "];
+    if (characters.length == 1 && [characters stringByTrimmingCharactersInSet:allowedCharacters].length == 0) {
         MPExpression *targetExpression = [self.expressionStorage elementAtIndexPath:[self.selection.location indexPathByRemovingLastIndex]];
         [targetExpression replaceSymbolsInRange:self.selection.rangeAtLastIndex withElements:@[characters]];
         self.selection = MPMakeRangePath([self.selection.location indexPathByIncrementingLastIndex], 0);
@@ -277,7 +283,8 @@
 
 - (void)moveToEndOfLine:(id)sender
 {
-    
+    MPExpression *targetExpression = [self.expressionStorage elementAtIndexPath:[self.selection.location indexPathByRemovingLastIndex]];
+    self.selection = MPMakeRangePath([self.selection.location indexPathByReplacingLastIndexWithIndex:targetExpression.length], 0);
 }
 
 - (void)moveLeftAndModifySelection:(id)sender
@@ -317,12 +324,12 @@
 
 - (void)moveWordRightAndModifySelection:(id)sender
 {
-    
+#warning Unimplemented Method
 }
 
 - (void)moveWordLeftAndModifySelection:(id)sender
 {
-    
+#warning Unimplemented Method
 }
 
 - (void)selectAll:(id)sender
@@ -361,7 +368,7 @@
     // Draw the background
     [super drawRect:dirtyRect];
     [[NSColor whiteColor] set];
-    NSRectFill(self.bounds);
+    NSRectFill(dirtyRect);
     
     // Calculate the position of the expression (probably also forces layout of the expression the first time)
     NSPoint expressionOrigin = self.expressionOrigin;

MathPad/MPFunction.h

@@ -37,7 +37,7 @@
 - (id)elementAtIndexPath:(NSIndexPath *)indexPath;
 
 #pragma mark Evaluating Functions
-- (double)doubleValue; // Override
+- (double)evaluateFunction:(NSError *__autoreleasing *)error;
 
 #pragma mark Messages
 - (void)didChangeElementsInRangePath:(MPRangePath *)rangePath
@@ -46,7 +46,7 @@
 - (void)didChangeChildAtIndex:(NSUInteger)index;
 
 #pragma mark Working With Functions
-- (BOOL)isEqualToFunction:(MPFunction *)aFunction; // Override
+// - (BOOL)isEqualToFunction:(MPFunction *)aFunction; // Override
 
 - (NSString *)description; // Should be overridden
 - (NSUInteger)hash;// Override

MathPad/MPFunction.m

@@ -82,7 +82,7 @@
 }
 
 #pragma mark Evaluating Functions
-- (double)doubleValue
+- (double)evaluateFunction:(NSError *__autoreleasing *)error
 {
     return 0;
 }
@@ -92,8 +92,7 @@
                    replacementLength:(NSUInteger)replacementLength
 {
     NSUInteger selfIndex = [self.parent indexOfElement:self];
-    MPRangePath *newPath = rangePath.copy;
+    MPRangePath *newPath = MPMakeRangePath([rangePath.location indexPathByPreceedingIndex:selfIndex], rangePath.length);
-    newPath.location = [newPath.location indexPathByPreceedingIndex:selfIndex];
     [self.parent didChangeElementsInRangePath:newPath
                             replacementLength:replacementLength];
 }

MathPad/MPLayout.h

@@ -41,6 +41,8 @@
 - (void)invalidate;
 
 #pragma mark Calculation and Drawing Methods
+- (CTLineRef)createLineForString:(NSString *)aString;
+
 @property (nonatomic, getter = isFlipped) BOOL flipped;
 @property (nonatomic) BOOL usesSmallSize;
 - (NSRect)bounds;

MathPad/MPLayout.m

@@ -128,6 +128,16 @@
 }
 
 #pragma mark Calculation and Drawing Methods
+- (CTLineRef)createLineForString:(NSString *)aString
+{
+    NSAttributedString *text = [[NSAttributedString alloc] initWithString:aString
+                                                               attributes:@{NSFontAttributeName: self.font}];
+    CFAttributedStringRef attributedString = CFBridgingRetain(text);
+    CTLineRef line = CTLineCreateWithAttributedString(attributedString);
+    CFRelease(attributedString); // TODO: Is this release appropriate?
+    return line;
+}
+
 - (NSRect)bounds
 {
     if (NSEqualRects(_cachedBounds, NSZeroRect)) {
@@ -162,32 +172,3 @@
 }
 
 @end
-
-@implementation MPLayout (MPSubclassImplement)
-
-- (MPLayout *)childLayoutAtIndex:(NSUInteger)index
-{
-    return nil;
-}
-
-- (NSRect)generateBounds
-{
-    return NSZeroRect;
-}
-
-- (NSRect)boundingRectForRange:(NSRange)range
-{
-    return NSZeroRect;
-}
-
-- (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
-{
-    return NSZeroPoint;
-}
-
-- (void)draw
-{
-    
-}
-
-@end

MathPad/MPSumFunction.m

@@ -97,10 +97,10 @@
 }
 
 #pragma mark Evaluating Functions
-- (double)doubleValue
+- (double)evaluateFunction:(NSError *__autoreleasing *)error
 {
 #warning Unimplemented Method
-    return 0;
+    return 0.0;
 }
 
 #pragma mark Working With Functions

MathPad/MPSumFunctionLayout.m

@@ -26,13 +26,7 @@
 - (CTLineRef)line
 {
     CTLineRef line = [self lineForPrivateCacheIndex:0 generator:^CTLineRef{
-        NSAttributedString *text =
+        return [self createLineForString:@"∑"];
-            [[NSAttributedString alloc] initWithString:@"∑"
-                                            attributes:@{NSFontAttributeName: self.font}];
-        CFAttributedStringRef attributedString = CFBridgingRetain(text);
-        CTLineRef line = CTLineCreateWithAttributedString(attributedString);
-        CFRelease(attributedString); // TODO: Is this release appropriate
-        return line;
     }];
     return line;
 }