Added Lots of Documentation

Added some nice to haves
Improved and Unified General Code Layout

MathKit/MPElementaryFunctionTerm.h

@@ -9,15 +9,63 @@
 #import "MPTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPElementaryFunction</code> class.
+ */
+
+
 
 @class MPElementaryFunctionTerm;
 
 
+/*!
+    @class      MPElementaryFunctionTerm
+    @abstract   A <code>MPElementaryFunction</code> implements various
+                mathematical functions that have a valid text representation.
+ */
 @interface MPElementaryFunctionTerm : MPTerm
 
+/*!
+    @method     initWithFunctionIdentifier:term:
+    @abstract   Initializes a function term using the specified textual
+                representation of the function and a term as its value.
+ 
+    @param      function
+                The textual representation of the function to use. Valid values
+                are <code>"sin"</code>, <code>"cos"</code>, <code>"tan"</code>,
+                <code>"asin"</code>, <code>"arcsin"</code>, <code>"acos"</code>,
+                <code>"arccos"</code>, <code>"atan"</code>,
+                <code>"arctan"</code>, <code>"log"</code>, <code>"lg"</code> and
+                <code>"ln"</code>.
+ 
+    @param      term
+                The term that should be evaluated using <code>function</code>.
+ 
+    @return     A new <code>MPElementaryFunctionTerm</code> instance.
+ */
 - (instancetype)initWithFunctionIdentifier:(NSString *)function
                                       term:(MPTerm *)term; /* designated initializer */
 
+
+/*!
+    @property   functionIdentifier
+    @abstract   The identifier of the receiver.
+ 
+    @discussion The identifier of a function is the string of letters it is
+                mathematically defined of (e.g. <code>"sin"</code> for the sine
+                function).
+ */
+@property (readonly, nonatomic, copy) NSString *functionIdentifier;
+
+
+/*!
+    @property   term
+    @abstract   The receiver's term.
+ 
+    @discussion Depending on the actual function the value of the
+                <code>term</code> may be converted from radians into degrees.
+ */
 @property (readonly, nonatomic, strong) MPTerm *term;
 
 @end

MathKit/MPElementaryFunctionTerm.m

@@ -9,13 +9,10 @@
 #import "MPElementaryFunctionTerm.h"
 
 #import "MPParsedExpression.h"
-#import "MPPowerFunction.h"
-#import "MPProductTerm.h"
-#import "MPToken.h"
-
-#import "MPExpression.h"
 #import "MPMathRules.h"
 
+
+
 @implementation MPElementaryFunctionTerm {
     NSDecimalNumber *(^_function)(NSDecimalNumber *);
 }
@@ -53,16 +50,18 @@
         } else if ([function isEqualToString:@"ln"]) {
             func = &log;
         } else {
-            NSAssert(true, @"function must be one of (sin, cos, tan, asin, acos, atan, lg, log, ln).");
+            NSAssert(true, @"function must be one of (sin, cos, tan, asin, arcsin, acos, arccos, atan, arctan, lg, log, ln).");
         }
         [self setFunction:func
             takesArcValue:takesArc
           returnsArcValue:returnsArc];
         _term = term;
+        _functionIdentifier = function.copy;
     }
     return self;
 }
 
+
 - (void)setFunction:(double (*)(double))function
       takesArcValue:(BOOL)takesArc
     returnsArcValue:(BOOL)returnsArc
@@ -80,6 +79,7 @@
     };
 }
 
+
 - (NSDecimalNumber *)convertToRadiantsIfNecessary:(NSDecimalNumber *)degrees
 {
     if ([MPMathRules sharedRules].isUsingDegrees) {
@@ -90,6 +90,7 @@
     }
 }
 
+
 - (NSDecimalNumber *)convertToDegreesIfNecessary:(NSDecimalNumber *)radiants
 {
     if ([MPMathRules sharedRules].isUsingDegrees) {
@@ -100,13 +101,24 @@
     }
 }
 
+
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
     NSDecimalNumber *value = [self.term evaluate:error];
     if (!value) {
         return nil;
     }
-    return _function(value);
+    NSDecimalNumber *result = _function(value);
+    if ([result isEqualToNumber:[NSDecimalNumber notANumber]]) {
+        result = nil;
+        if (error) {
+            NSString *errorDescription = [NSString stringWithFormat:NSLocalizedString(@"%@ is not defined for the value %@.", nil), self.functionIdentifier, [value descriptionWithLocale:[NSLocale currentLocale]]];
+            *error = [NSError errorWithDomain:MPMathKitErrorDomain
+                                         code:102
+                                     userInfo:@{NSLocalizedDescriptionKey: errorDescription}];
+        }
+    }
+    return result;
 }
 
 @end

MathKit/MPEvaluationContext.h

@@ -7,21 +7,117 @@
 //
 
 
+/*!
+ @header
+ This file contains the <code>MPEvaluationContext</code> class.
+ 
+ The evaluation context is organized in so called levels. Every level of a
+ context contains a unique set of variables. Only the highest level is
+ accessible. Before any lower level can be accessed the higher ones have to be
+ discarded. A higher level can not define variables that are already defined in
+ a lower level. Similarly variables can only be undefined if they are defined at
+ the current level. Discarding (popping) a level always undefines all variables
+ defined on that level.
+ */
+
+
 
 @class MPEvaluationContext;
 
 
+/*!
+    @class      MPEvaluationContext
+    @abstract   The evaluation context maintains a map of variables and
+                associates them with a certain level.
+ 
+    @discussion Different levels are nested using <code>@link
+                //apple_ref/occ/instm/MPEvaluationContext/push@/link</code> and
+                <code>@link
+                //apple_ref/occ/instm/MPEvaluationContext/pop@/link</code>
+                messages.
+ 
+                <code>MPEvaluationContext</code> is a singletone class. There can
+                only exist one instance (the shared instance) at any time.
+ */
 @interface MPEvaluationContext : NSObject
 
+/*!
+    @method     sharedContext
+    @abstract   Returns the shared evaluation context.
+ */
 + (MPEvaluationContext *)sharedContext;
 
+
+/*!
+    @method     push
+    @abstract   Pushes a new level on context.
+ */
 - (void)push;
+
+
+/*!
+    @method     pop
+    @abstract   Pops a level off the context.
+ 
+    @discussion Popping a level also undefines all variables that were defined in
+                that level.
+ */
 - (void)pop;
 
+
+/*!
+    @method     defineVariable:value:
+    @abstract   Defines a variable with the specified value at the current level.
+ 
+    @discussion The variable can only be defined if it has not been defined
+                previously in a lower level. If the variable has been defined at
+                the current level its value will be overwritten to the specified
+                one.
+ 
+    @param      variable
+                The name of the variable. Typically this is a one-letter string.
+ 
+    @param      value
+                The value of the variable.
+ 
+    @return     <code>YES</code> if the variable was defined successfully,
+                <code>NO</code> if it is already defined in a lower level.
+ */
 - (BOOL)defineVariable:(NSString *)variable
                  value:(NSDecimalNumber *)value;
+
+
+/*!
+    @method     undefineVariable:
+    @abstract   Undefines a variable that has previously been defined.
+ 
+    @discussion Variables can only be undefined if they have been defined at the
+                same level. If the variable to be undefined was defined at a
+                different level this method does nothing.
+ 
+                Normally there is very little reason to call this method since
+                all variables defined on one level are automatically undefined
+                when the level is popped.
+ 
+    @param      variable
+                The variable to be undefined.
+ */
 - (void)undefineVariable:(NSString *)variable;
 
+
+/*!
+    @method     valueForVariable:
+    @abstract   Returns the value for the specified variable.
+ 
+    @discussion If the <code>variable</code> has not been defined previously this
+                method returns <code>nil</code>.
+ 
+    @param      variable
+                The variable whose value is to be retrieved.
+ 
+    @return     The value <code>variable</code> was defined with or
+                <code>nil</code> if it was not defined.
+ */
 - (NSDecimalNumber *)valueForVariable:(NSString *)variable;
 
 @end

MathKit/MPEvaluationContext.m

@@ -8,13 +8,21 @@
 
 #import "MPEvaluationContext.h"
 
+
+
 @interface MPEvaluationContext ()
+
 @property (nonatomic, strong) NSMutableArray *stack;
+
 @end
 
+
+
 @implementation MPEvaluationContext
 
 static MPEvaluationContext *sharedContext;
+
+
 + (MPEvaluationContext *)sharedContext
 {
     if (!sharedContext) {
@@ -23,6 +31,7 @@ static MPEvaluationContext *sharedContext;
     return sharedContext;
 }
 
+
 - (instancetype)init
 {
     if (sharedContext) {
@@ -40,16 +49,19 @@ static MPEvaluationContext *sharedContext;
     return self;
 }
 
+
 - (void)push
 {
     [self.stack addObject:[[NSMutableDictionary alloc] init]];
 }
 
+
 - (void)pop
 {
     [self.stack removeLastObject];
 }
 
+
 - (BOOL)defineVariable:(NSString *)variable
                  value:(NSDecimalNumber *)value
 {
@@ -62,17 +74,20 @@ static MPEvaluationContext *sharedContext;
     return YES;
 }
 
+
 - (void)undefineVariable:(NSString *)variable
 {
     NSMutableDictionary *currentBindings = self.stack.lastObject;
     [currentBindings removeObjectForKey:variable];
 }
 
+
 - (BOOL)isVariableDefined:(NSString *)variable
 {
     return [self valueForVariable:variable] != nil;
 }
 
+
 - (NSDecimalNumber *)valueForVariable:(NSString *)variable
 {
     NSUInteger currentIndex = self.stack.count;

MathKit/MPExpression.h

@@ -10,6 +10,9 @@
 
 /*!
  @header
+ This file contains the <code>MPExpression</code> class and the
+ <code>MPExpressionElement</code> protocol.
+
  The <code>MPExpression</code> class is used to represent a mathematical
  expression. It is used in the storage layer of the MathKit Expression System. An
  instance of the <code>MPExpression</code> class stores all contents related to
@@ -108,6 +111,58 @@
  */
 
 
+/*!
+    @const      MPIllegalElementException
+    @abstract   Name for an exception that is raised if an invalid element is
+                added to an expression.
+ 
+    @discussion This exception may be raised during initialization of an
+                expression or when the expression is mutated. This exception
+                contains the invalid element in its <code>userInfo</code>
+                dictionary. You can query it using the
+                <code>MPIllegalElementExceptionElementKey</code> key.
+ */
+FOUNDATION_EXPORT NSString *const MPIllegalElementException;
+
+
+/*!
+    @const      MPIllegalElementExceptionElementKey
+    @abstract   Predefined key for an invalid element that caused a
+                <code>MPIllegalElementException</code> to be raised.
+ 
+    @discussion The invalid element can be of any type. Numbers and structs are
+                wrapped in an <code>NSNumber</code> or <code>NSValue</code>
+                instance respectively.
+ */
+FOUNDATION_EXPORT NSString *const MPIllegalElementExceptionElementKey;
+
+
+/*!
+    @typedef    MPReferenceFrame
+    @abstract   A reference frame specifies the way an <i>item</i> is to be
+                interpreted.
+ 
+    @constant   MPElementReferenceFrame
+                Specifies that items should be interpreted as elements.
+ 
+    @constant   MPSymbolReferenceFrame
+                Specifies that items should be interpreted as symbols.
+ 
+    @constant   MPTokenReferenceFrame
+                Specifies that items should be interpreted as tokens.
+  */
+typedef enum {
+    MPElementReferenceFrame,
+    MPSymbolReferenceFrame,
+    MPTokenReferenceFrame
+} MPReferenceFrame;
+
+
+
+@class MPExpression, MPFunction, MPRangePath, MPParsedExpression;
+@protocol MPExpressionElement, MPToken;
+
+
 /*!
     @protocol   MPExpressionElement
     @abstract   This protocol defines the functionality an element in an
@@ -161,58 +216,6 @@
 
 
 
-/*!
-    @const      MPIllegalElementException
-    @abstract   Name for an exception that is raised if an invalid element is
-                added to an expression.
- 
-    @discussion This exception may be raised during initialization of an
-                expression or when the expression is mutated. This exception
-                contains the invalid element in its <code>userInfo</code>
-                dictionary. You can query it using the
-                <code>MPIllegalElementExceptionElementKey</code> key.
- */
-FOUNDATION_EXPORT NSString *const MPIllegalElementException;
-
-
-/*!
-    @const      MPIllegalElementExceptionElementKey
-    @abstract   Predefined key for an invalid element that caused a
-                <code>MPIllegalElementException</code> to be raised.
- 
-    @discussion The invalid element can be of any type. Numbers and structs are
-                wrapped in an <code>NSNumber</code> or <code>NSValue</code>
-                instance respectively.
- */
-FOUNDATION_EXPORT NSString *const MPIllegalElementExceptionElementKey;
-
-
-/*!
-    @typedef    MPReferenceFrame
-    @abstract   A reference frame specifies the way an <i>item</i> is to be
-                interpreted.
- 
-    @constant   MPElementReferenceFrame
-                Specifies that items should be interpreted as elements.
- 
-    @constant   MPSymbolReferenceFrame
-                Specifies that items should be interpreted as symbols.
- 
-    @constant   MPTokenReferenceFrame
-                Specifies that items should be interpreted as tokens.
-  */
-typedef enum {
-    MPElementReferenceFrame,
-    MPSymbolReferenceFrame,
-    MPTokenReferenceFrame
-} MPReferenceFrame;
-
-
-
-@class MPExpression, MPFunction, MPRangePath, MPParsedExpression;
-@protocol MPExpressionElement, MPToken;
-
-
 /*!
     @class      MPExpression
     @abstract   A <code>MPExpression</code> instance represents a mathematical

MathKit/MPExpression.m

@@ -21,11 +21,11 @@
 #import "NSIndexPath+MPAdditions.h"
 
 
-
 NSString *const MPIllegalElementException = @"Illegal Element Exception";
 NSString *const MPIllegalElementExceptionElementKey = @"MPIllegalElementExceptionElementKey";
 
 
+
 @interface MPExpression () {
     NSMutableArray * _elements;
 }
@@ -299,7 +299,6 @@ NSString *const MPIllegalElementExceptionElementKey = @"MPIllegalElementExceptio
 }
 
 
-#warning If multiple equal expressions exist errors may occur...
 - (NSUInteger)indexOfElement:(id<MPExpressionElement>)element
 {
     return [_elements indexOfObject:element];
@@ -656,7 +655,7 @@ NSString *const MPIllegalElementExceptionElementKey = @"MPIllegalElementExceptio
 
 - (NSString *)description
 {
-#warning Bad Implementation
+#warning Incomplete Implementation
     NSMutableString *description = [[NSMutableString alloc] init];
     NSUInteger index = 0;
     for (id element in _elements) {

MathKit/MPExpressionLayout.h

@@ -9,14 +9,53 @@
 #import "MPLayout.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPExpressionLayout</code> class.
+ */
+
+
 
 @class MPExpressionLayout, MPExpression, MPFunctionLayout;
 
+
+/*!
+    @class      MPExpressionLayout
+    @abstract   An expression layout draws an <code>@link
+                //apple_ref/occ/cl/MPExpression@/link</code>.
+ 
+    @discussion For more information on the layout system see the documentation
+                on the <code>@link //apple_ref/occ/cl/MPLayout@/link</code>
+                class.
+ */
 @interface MPExpressionLayout : MPLayout
 
+/*!
+    @method     initWithExpression:parent:
+    @abstract   Initializes an expression layout with the specified expression
+                and parent layout.
+ 
+    @discussion To initialize a layout for the root expression of an expression
+                tree specify <code>nil</code> as the <code>parent</code>.
+ 
+    @param      expression
+                The expression that sould be represented by the receiver. Must
+                not be <code>ni</code>.
+ 
+    @param      parent
+                The parent layout of the receiver. Specify <code>nil</code> to
+                initalize a root expression layout.
+ 
+    @return     A newly initialized expression layout.
+ */
 - (instancetype)initWithExpression:(MPExpression *)expression
                             parent:(MPFunctionLayout *)parent;
 
+
+/*!
+    @property   expression
+    @abstract   The expression represented by the receiver.
+ */
 @property (readonly, nonatomic, weak) MPExpression *expression;
 
 @end

MathKit/MPExpressionLayout.m

@@ -9,21 +9,23 @@
 #import "MPExpressionLayout.h"
 
 #import "MPExpression.h"
-#import "MPExpression.h"
-#import "MPPowerFunction.h"
-
+#import "MPFunction.h"
 #import "MPFunctionLayout.h"
 #import "MPPowerFunctionLayout.h"
 
 #import "MPToken.h"
 #import "NSIndexPath+MPAdditions.h"
 
+
+
 @interface MPExpressionLayout (MPLineGeneration)
 
 - (CTLineRef)lineForElementAtIndex:(NSUInteger)index;
 
 @end
 
+
+
 @implementation MPExpressionLayout (MPLineGeneration)
 
 - (CTLineRef)lineForElementAtIndex:(NSUInteger)index
@@ -60,9 +62,13 @@
 
 @end
 
+
+
 @implementation MPExpressionLayout
 
 # pragma mark Creation Methods
+
+
 - (instancetype)initWithExpression:(MPExpression *)expression
                             parent:(MPFunctionLayout *)parent
 {
@@ -73,12 +79,16 @@
     return self;
 }
 
+
 #pragma mark Cache Methods
+
+
 - (NSUInteger)numberOfChildren
 {
     return self.expression.countElements;
 }
 
+
 - (MPLayout *)childLayoutAtIndex:(NSUInteger)index
 {
     id cachedObject = [self cachableObjectForIndex:index generator:^id{
@@ -95,6 +105,7 @@
     return nil;
 }
 
+
 - (NSRect)boundsOfElementAtIndex:(NSUInteger)index
 {
     id symbol = [self.expression elementAtIndex:index];
@@ -109,7 +120,10 @@
     }
 }
 
+
 #pragma mark Drawing Methods
+
+
 - (NSRect)generateBounds
 {
     if (self.expression.countElements == 0) {
@@ -125,6 +139,7 @@
     return NSMakeRect(x, y, width, height);
 }
 
+
 - (NSRect)boundingRectForRange:(NSRange)range
 {
     NSUInteger startOffset;
@@ -184,6 +199,7 @@
     return NSMakeRect(x, self.bounds.origin.y, width, self.bounds.size.height);
 }
 
+
 - (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
 {
     CGFloat x = 0;
@@ -193,6 +209,7 @@
     return NSMakePoint(x, 0);
 }
 
+
 - (NSIndexPath *)indexPathForMousePoint:(NSPoint)point
 {
     NSUInteger currentPosition = 0;
@@ -235,11 +252,13 @@
     }
 }
 
+
 - (BOOL)drawsChildrenManually
 {
     return YES;
 }
 
+
 - (void)draw
 {
     // Get the current context

MathKit/MPExpressionParser.h

@@ -9,6 +9,8 @@
 
 /*!
  @header
+ This file contains the <code>MPExpressionParser</code> class.
+ 
  The <code>MPExpressionParser</code> converts a <code>@link
  MPExpression@/link</code> instance into a <code>@link
  //apple_ref/occ/cl/MPParsedExpression@/link</code> instance. The rules that are

MathKit/MPExpressionParser.m

@@ -8,25 +8,27 @@
 
 #import "MPExpressionParser.h"
 
-#import "MPExpression.h"
-#import "MPTerm.h"
 #import "MPToken.h"
+#import "MPExpression.h"
+#import "MPParsedExpression.h"
+
+#import "MPTerm.h"
 #import "MPSumTerm.h"
 #import "MPProductTerm.h"
-#import "MPFactorialTerm.h"
-#import "MPElementaryFunctionTerm.h"
-#import "MPFunctionTerm.h"
-#import "MPPowerTerm.h"
-#import "MPParsedExpression.h"
 #import "MPNegatedTerm.h"
-
+#import "MPFunctionTerm.h"
+#import "MPElementaryFunctionTerm.h"
 #import "MPNumber.h"
 #import "MPVariable.h"
 #import "MPFactorialTerm.h"
+#import "MPPowerTerm.h"
+
 
 #define success() state = 0
 #define fail() self.errorTokenIndex = self.currentTokenIndex; state = -1
 
+
+
 @interface MPExpressionParser ()
 
 @property (nonatomic, strong) NSArray *tokens;
@@ -46,6 +48,8 @@
 
 @end
 
+
+
 @implementation MPExpressionParser
 
 - (instancetype)initWithExpression:(MPExpression *)expression
@@ -58,12 +62,14 @@
     return self;
 }
 
+
 - (MPParsedExpression *)parse:(NSArray *__autoreleasing *)errors
 {
     return [self parseExpectingVariableDefinition:NO
                                            errors:errors];
 }
 
+
 - (MPParsedExpression *)parseExpectingVariableDefinition:(BOOL)flag
                                                   errors:(NSArray *__autoreleasing *)errors
 {
@@ -120,6 +126,7 @@
     return result;
 }
 
+
 - (void)runParserMachine
 {
     NSInteger state = 1;
@@ -251,6 +258,7 @@
     }
 }
 
+
 - (void)skipWhitespaces
 {
     while ([self currentToken] != nil && [self currentToken].tokenType == MPWhitespaceToken) {
@@ -258,6 +266,7 @@
     }
 }
 
+
 - (id<MPToken>)currentToken
 {
     if (self.currentTokenIndex >= self.tokens.count) {
@@ -266,11 +275,13 @@
     return self.tokens[self.currentTokenIndex];
 }
 
+
 - (void)nextToken
 {
     self.currentTokenIndex++;
 }
 
+
 - (NSMutableArray *)errors
 {
     if (!_errors) {
@@ -279,6 +290,7 @@
     return _errors;
 }
 
+
 - (NSMutableArray *)summands
 {
     if (!_summands) {
@@ -287,6 +299,7 @@
     return _summands;
 }
 
+
 - (NSMutableArray *)factors
 {
     if (!_factors) {
@@ -295,6 +308,7 @@
     return _factors;
 }
 
+
 - (NSMutableArray *)functionStack
 {
     if (!_functionStack) {
@@ -303,6 +317,7 @@
     return _functionStack;
 }
 
+
 - (NSMutableArray *)valueGroup
 {
     if (!_valueGroup) {
@@ -311,6 +326,7 @@
     return _valueGroup;
 }
 
+
 - (BOOL)parseOperatorList:(id<MPToken>)token // Returns YES if list is overall negative
 {
     NSString *operatorString = [[token.stringValue stringByReplacingOccurrencesOfString:@" " withString:@""]
@@ -318,17 +334,20 @@
     return (operatorString.length & 1) == 1;
 }
 
+
 - (NSDecimalNumber *)parseNumber:(id<MPToken>)token
 {
     return [NSDecimalNumber decimalNumberWithString:token.stringValue
                                              locale:[NSLocale currentLocale]];
 }
 
+
 - (NSString *)parseVariable:(id<MPToken>)token
 {
     return token.stringValue;
 }
 
+
 - (void)collapseSummand
 {
     if (self.factors.count > 0) {
@@ -342,6 +361,7 @@
     self.summandNegative = NO;
 }
 
+
 - (void)collapseFactor
 {
     if (self.valueGroup.count > 0) {
@@ -360,6 +380,7 @@
     self.factorNegative = NO;
 }
 
+
 - (void)runSuffixMachine
 {
     BOOL checkMore = YES;
@@ -388,6 +409,7 @@
     }
 }
 
+
 - (void)addErrorWithCode:(NSInteger)code
     localizedDescription:(NSString *)description
                 useRange:(BOOL)flag
@@ -408,6 +430,7 @@
                                                       MPErrorRangeKey: [NSValue valueWithRange:errorRange]}]];
 }
 
+
 - (BOOL)errorOccured
 {
     [self skipWhitespaces];

MathKit/MPExpressionStorage.h

@@ -9,13 +9,51 @@
 #import "MPExpression.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPExpressionStorage</code> class.
+ */
+
+
 
 @class MPExpressionStorage, MPExpressionView, MPExpressionLayout;
 
 
+/*!
+    @class      MPExpressionStorage
+    @abstract   An expression storage manages the contents of an expression view
+                and notifies it when the underlying expression changes.
+ */
 @interface MPExpressionStorage : MPExpression
 
-@property (nonatomic, weak) MPExpressionView *expressionView; // Do not set
+/*!
+    @property   expressionView
+    @abstract   The receiver's expression view.
+ 
+    @discussion The expression view is the view that displays the contents of the
+                expression storage. Normally you should not call the setter of
+                this property. It is automatically assigned when the <code>@link
+                //apple_ref/occ/instp/MPExpressionView/expressionStorage@/link</code>
+                property of the <code>@link
+                //apple_ref/occ/cl/MPExpressionView@/link</code> class is set.
+ 
+                When this property is set the receiver assumes that the
+                displaying expression view has changed. It then adapts to the
+                properties of the new expression view and discards the root
+                layout.
+ */
+@property (nonatomic, weak) MPExpressionView *expressionView;
+
+
+/*!
+    @property   rootLayout
+    @abstract   The receiver's root layout.
+ 
+    @discussion The root layout is the root node of the layout tree that draws
+                the receiver's contents. For more information see the
+                documentation on the <code>@link
+                //apple_ref/occ/cl/MPLayout@/link</code> class.
+ */
 @property (nonatomic, strong) MPExpressionLayout *rootLayout;
 
 @end

MathKit/MPExpressionStorage.m

@@ -9,17 +9,22 @@
 #import "MPExpressionStorage.h"
 
 #import "MPExpressionView.h"
-#import "MPLayout.h"
 #import "MPExpressionLayout.h"
 
 #import "MPRangePath.h"
 
+
+
 @interface MPExpressionStorage ()
+
 @property (nonatomic, strong) NSLayoutManager *layoutManager;
 @property (nonatomic, strong) NSTextContainer *textContainer;
 @property (nonatomic, strong) NSTextStorage *textStorage;
+
 @end
 
+
+
 @implementation MPExpressionStorage
 
 - (instancetype)initWithElements:(NSArray *)elements
@@ -31,6 +36,7 @@
     return self;
 }
 
+
 - (void)setExpressionView:(MPExpressionView *)expressionView
 {
     _expressionView = expressionView;
@@ -38,6 +44,7 @@
     self.rootLayout.flipped = expressionView.flipped;
 }
 
+
 - (void)changedElementsInRangePath:(MPRangePath *)rangePath
                    replacementLength:(NSUInteger)replacementLength
 {

MathKit/MPExpressionTokenizer.h

@@ -7,6 +7,12 @@
 //
 
 
+/*!
+ @header
+ This file contains the <code>MPExpressionTokenizer</code> class.
+ */
+
+
 
 @class MPExpressionTokenizer, MPExpression;
 

MathKit/MPExpressionTokenizer.m

@@ -52,7 +52,7 @@
                             @"((?:\\d+%@(?!\\d+))|(?:(?:\\d*%@){2,}\\d*)|%@(?!\\d+))|" // Substitute with decimal separator 3 times
                             @"((?:\\d+(?:%@\\d+)?)|(?:%@\\d+))|" // Substitute with decimal separator 2 times
                             @"(sin|cos|tan|asin|arcsin|acos|arccos|atan|arctan|lg|log|ln)|"
-                            @"([A-Za-z])|"
+                            @"([A-Za-zπ])|"
                             @"(!)|"
                             @"(=)|"
                             @"(\\s+)"

MathKit/MPExpressionView.h

@@ -6,68 +6,195 @@
 //  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
 //
 
-// TODO: Undo/Redo + Delegate (evaluateExpressionView:evaluate...)
+
+/*!
+ @header
+ This file contains the <code>MPExpressionView</code> class.
+ 
+ <h2>The MathKit Expression System</h2>
+ MathKit contains class es that make up the so called <i>expression system</i>.
+ The expression system is divided into three layers: the model, the view and the
+ controller layer. The <code>MPExpressionView</code> class represents the view
+ layer and interacts with the Cocoa <code>NSView</code> system. The model is
+ represented by the classes <code>@link
+ //apple_ref/occ/cl/MPExpression@/link</code> and <code>@link
+ //apple_ref/occ/cl/MPFunction@/link</code>. The controller layer between the two
+ consists of the class <code>@link //apple_ref/occ/cl/MPLayout@/link</code> and
+ its subclasses. The purpose of the expression system is presenting expressions
+ to the user and offering possibilities to manipulate and work with expressions.
+ */
 
 
 
 @class MPExpressionView, MPExpressionStorage, MPFunction, MPRangePath;
-//@protocol MPExpressionViewDelegate;
 
 
+/*!
+    @class      MPExpressionView
+    @abstract   The <code>MPExpressionView</code> class is the front-end class of
+                the MathKit expression system.
+ 
+    @discussion The class draws the expression managed by the the back-end class
+                <code>@link //apple_ref/occ/cl/MPExpressionStorage@/link</code>
+                and is the interface between Application Kit's view system and
+                the MathKit expression system.
+ */
 @interface MPExpressionView : NSView <NSUserInterfaceValidations>
 
 #pragma mark Creation Methods
+/*!
+ @methodgroup Creation Methods
+ */
 
+
+/*!
+    @method     initWithFrame:
+    @abstract   Initializes a <code>MPExpressionView</code> instance.
+ 
+    @discussion This method sets up all layers of the expression system including
+                an empty expression storage.
+ 
+                This method is the designated initializer of the
+                <code>MPExpressionView</code> class.
+ 
+    @param      frameRect
+                The frame rectangle for the created view.
+ 
+    @return     An initialized <code>MPExpressionView</code> or <code>nil</code>
+                if the object could not be created.
+ */
 - (id)initWithFrame:(NSRect)frameRect;
 
+
 #pragma mark Properties
+/*!
+ @methodgroup Properties
+ */
 
-@property (readonly, nonatomic, strong) MPExpressionStorage *expressionStorage;
 
-//@property (nonatomic, weak) id<MPExpressionViewDelegate> delegate;
+/*!
+    @property   expressionStorage
+    @abstract   The receiver's expression storage.
  
+    @discussion The expression storage maintains the contents of the receiver.
+                User interactions change the underlying data. If the expression
+                storage or the underlying expression change the expression
+                storage updates the receiver.
+ */
+@property (nonatomic, strong) MPExpressionStorage *expressionStorage;
+
+
+/*!
+    @property   selection
+    @abstract   The receiver's selection.
+ */
 @property (nonatomic, strong) MPRangePath *selection;
 
+
+/*!
+    @property   mathError
+    @abstract   If set the receiver will display the localized description of the
+                specified error.
+ 
+    @discussion There can only be one math error at a time. This property should
+                not be set simutaneously with the <code>@link
+                //apple_ref/occ/instp/MPExpressionView/syntaxErrors@/link</code>.
+ */
 @property (nonatomic, strong) NSError *mathError;
+
+
+/*!
+    @property   syntaxErrors
+    @abstract   If set the receiver will display a dropdown list of syntax
+                errors.
+ 
+    @discussion The array must only contain <code>NSError</code> instances. In
+                addition to that every instance must contain a valid
+                <code>NSIndexPath</code> for the <code>@link
+                //apple_ref/c/data/MPPathToExpressionKey@/link</code> in its
+                <code>userDict</code> acompanied by a <code>NSRange</code> 
+                wrapped in a <code>NSValue</code> instance for the <code>@link
+                //apple_ref/c/data/MPErrorRangeKey@/link</code>.
+ 
+                If the user selects an item from the dropdown list the part of
+                the expression displayed by the receiver will be selected that is
+                specified by the values in the corresponding <code>NSError</code>
+                instance.
+ */
 @property (nonatomic, strong) NSArray *syntaxErrors;
 
+
+/*!
+    @property   target
+    @abstract   The target object to receive action messages from the receiver.
+ */
 @property (nonatomic, weak) id target;
+
+
+/*!
+    @property   action
+    @abstract   The receiver's action method to the specified selector.
+ 
+    @discussion The action method is invoked when the user presses <i>enter</i>
+                in the receiver. Typically this is understood as evaluation
+                request.
+ */
 @property (nonatomic) SEL action;
 
-//@property (nonatomic) BOOL editable;
-//@property (nonatomic) BOOL selectable;
 
 #pragma mark Actions
-// Radians - Degrees
+/*!
+ @methodgroup Actions
+ */
+
+
+/*!
+    @method     switchToRadians:
+    @abstract   Tells the receiver that it should switch the interpretation of
+                trigonometric function values to radians.
+ 
+    @param      sender
+                Typically the object that invoked the method.
+ */
 - (IBAction)switchToRadians:(id)sender;
+
+
+/*!
+    @method     switchToDegrees:
+    @abstract   Tells the receiver that it should switch the interpretation of
+                trigonometric function values to degrees.
+ 
+    @param      sender
+                Typically the object that invoked the method.
+ */
 - (IBAction)switchToDegrees:(id)sender;
+
+
+/*!
+    @method     switchRadiansDegrees:
+    @abstract   Tells the receiver that it should switch the interpretation of 
+                trigonometric function values.
+ 
+    @discussion If the interpretation is currently degrees it is changed to
+                radians or vice versa.
+ 
+    @param      sender
+                Typically the object that invoked the method.
+ */
 - (IBAction)switchRadiansDegrees:(id)sender;
-// Functions
+
+
+/*!
+    @method     toggleFunctionsPopover:
+    @abstract   Tells the receiver to toggle the visibility of the functions
+                popover.
+ 
+    @discussion From the functions popover the user can select and insert
+                functions into the displayed expression
+ 
+    @param      sender
+                Typically the object that invoked the method.
+ */
 - (IBAction)toggleFunctionsPopover:(id)sender;
 
 @end
-
-
-//@protocol MPExpressionViewDelegate <NSObject>
-//@optional
-//
-//#pragma mark Editing
-//- (MPRangePath *)expressionView:(MPExpressionView *)expressionView willChangeSelectionFromRangePath:(MPRangePath *)oldSelection toRangePath:(MPRangePath *)newSelection;
-//- (void)expressionView:(MPExpressionView *)expressionView didChangeSelectionFromRangePath:(MPRangePath *)oldSelection toRangePath:(MPRangePath *)newSelection;
-//
-//- (BOOL)expressionView:(MPExpressionView *)expressionView shouldChangeSymbolsInRangePath:(MPRangePath *)rangePath replacementElements:(NSArray *)replacement;
-//- (BOOL)expressionView:(MPExpressionView *)expressionView shouldInsertFunction:(MPFunction *)function replacingRangePath:(MPRangePath *)currentSelection;
-//- (void)expressionViewDidChange:(MPExpressionView *)expressionView;
-//
-//- (BOOL)expressionViewShouldBeginEditing:(MPExpressionView *)expressionView;
-//- (BOOL)expressionViewShouldEndEditing:(MPExpressionView *)expressionView;
-//- (void)expressionViewDidBeginEditing:(MPExpressionView *)expressionView;
-//- (void)expressionDidEndEditing:(MPExpressionView *)expressionView;
-//
-//// TODO: Errors...
-//#pragma mark Evaluation
-//
-//- (BOOL)expressionViewShouldEvaluate:(MPExpressionView *)expressionView;
-//- (void)expressionViewDidEvaluate:(MPExpressionView *)expressionView;
-//
-//@end

MathKit/MPExpressionView.m

@@ -8,26 +8,25 @@
 
 #import "MPExpressionView.h"
 
-#import "MPExpression.h"
-#import "MPExpression.h"
-#import "MPParsedExpression.h"
-
-#import "MPPowerFunction.h"
-#import "MPParenthesisFunction.h"
-#import "MPFractionFunction.h"
-
-#import "MPToken.h"
-#import "MPRangePath.h"
-#import "MPMathRules.h"
-
 #import "MPExpressionStorage.h"
 #import "MPExpressionLayout.h"
-#import "MPFunctionLayout.h"
 
 #import "MPFunctionsViewController.h"
 
+#import "MPFunctionLayout.h"
+#import "MPFractionFunction.h"
+#import "MPParenthesisFunction.h"
+#import "MPPowerFunction.h"
+
+#import "MPParsedExpression.h"
+#import "MPMathRules.h"
+#import "MPToken.h"
+
+#import "MPRangePath.h"
 #import "NSIndexPath+MPAdditions.h"
 
+
+
 @interface MPExpressionView ()
 
 @property (nonatomic, strong) NSButton *functionsButton;
@@ -58,6 +57,7 @@
 
 
 @interface MPExpressionView (MPSelectionHelper)
+
 - (void)restartCaretTimer;
 - (void)updateCaret:(NSTimer *)timer;
 
@@ -101,6 +101,7 @@
     [self updateCaret:self.caretTimer];
 }
 
+
 - (void)updateCaret:(NSTimer *)timer
 {
     self.caretVisible = !self.caretVisible;
@@ -111,6 +112,7 @@
     [self setNeedsDisplayInRect:updatedRect];
 }
 
+
 - (NSRect)selectionRect
 {
     NSRect selectionRect = [self.expressionStorage.rootLayout boundingRectForRangePath:self.selection];
@@ -120,6 +122,7 @@
     return selectionRect;
 }
 
+
 - (NSIndexPath *)selectionToTheRightOf:(NSIndexPath *)selectionPath
                   byExtendingSelection:(BOOL)extendingSelection
                            selectWords:(BOOL)selectWords
@@ -186,6 +189,7 @@
     return [selectionPath indexPathByReplacingLastIndexWithIndex:locationInTarget];
 }
 
+
 - (NSIndexPath *)selectionToTheLeftOf:(NSIndexPath *)selectionPath
                  byExtendingSelection:(BOOL)extendingSelection
                           selectWords:(BOOL)selectWords
@@ -257,6 +261,7 @@
     return [selectionPath indexPathByReplacingLastIndexWithIndex:locationInTarget];
 }
 
+
 - (MPRangePath *)rangePathEnclosingAnchorPath:(NSIndexPath *)anchorPath
                              newSelectionPath:(NSIndexPath *)newSelectionPath
 {
@@ -312,9 +317,13 @@
 
 
 #pragma mark -
+
+
 @implementation MPExpressionView
 
 #pragma mark Creation Methods
+
+
 - (id)initWithFrame:(NSRect)frame
 {
     self = [super initWithFrame:frame];
@@ -324,6 +333,7 @@
     return self;
 }
 
+
 - (id)initWithCoder:(NSCoder *)aDecoder
 {
     self = [super initWithCoder:aDecoder];
@@ -333,6 +343,7 @@
     return self;
 }
 
+
 - (void)initializeExpressionView
 {
     // Setup the Expression Storage
@@ -348,6 +359,7 @@
     [self restartCaretTimer];
 }
 
+
 - (void)initializeButtons
 {
     NSButton *functionsButton = self.functionsButton;
@@ -368,6 +380,7 @@
                                                       constant:0]];
 }
 
+
 - (void)initializeErrorsViews
 {
     
@@ -394,34 +407,42 @@
                                                                    views:variableBindings]];
 }
 
+
 #pragma mark - NSView Configuration
+
+
 - (BOOL)acceptsFirstResponder
 {
     return YES;
 }
 
+
 - (BOOL)canBecomeKeyView
 {
     return YES;
 }
 
+
 - (BOOL)isOpaque
 {
     return YES;
 }
 
+
 - (void)resetCursorRects
 {
     [self addCursorRect:self.bounds
                  cursor:[NSCursor IBeamCursor]];
 }
 
+
 - (BOOL)becomeFirstResponder
 {
     [self restartCaretTimer];
     return [super becomeFirstResponder];
 }
 
+
 - (BOOL)resignFirstResponder
 {
     [self.caretTimer invalidate];
@@ -430,12 +451,14 @@
     return [super resignFirstResponder];
 }
 
+
 - (void)setFrame:(NSRect)frameRect
 {
     [self setNeedsLayout:YES];
     [super setFrame:frameRect];
 }
 
+
 - (NSSize)intrinsicContentSize
 {
     NSSize size = self.expressionStorage.rootLayout.bounds.size;
@@ -443,7 +466,10 @@
     return size;
 }
 
+
 #pragma mark - Properties
+
+
 - (void)setExpressionStorage:(MPExpressionStorage *)expressionStorage
 {
     _expressionStorage.expressionView = nil;
@@ -452,6 +478,7 @@
     [self invalidateIntrinsicContentSize];
 }
 
+
 - (void)setSelection:(MPRangePath *)selection
 {
     _selection = selection;
@@ -459,6 +486,7 @@
     self.needsDisplay = YES;
 }
 
+
 - (void)setSyntaxErrors:(NSArray *)syntaxErrors
 {
     _syntaxErrors = syntaxErrors;
@@ -491,12 +519,14 @@
     }
 }
 
+
 - (void)setMathError:(NSError *)mathError
 {
     _mathError = mathError;
     self.mathErrorTextField.stringValue = mathError != nil ? mathError.localizedDescription : @"";
 }
 
+
 - (NSButton *)functionsButton
 {
     if (!_functionsButton) {
@@ -520,6 +550,7 @@
     return _functionsButton;
 }
 
+
 - (NSPopUpButton *)syntaxErrorsPopUpButton
 {
     if (!_syntaxErrorsPopUpButton) {
@@ -539,6 +570,7 @@
     return _syntaxErrorsPopUpButton;
 }
 
+
 - (NSTextField *)mathErrorTextField
 {
     if (!_mathErrorTextField) {
@@ -555,6 +587,7 @@
     return _mathErrorTextField;
 }
 
+
 - (void)didSelectError:(NSPopUpButton *)sender
 {
     NSError *error = self.syntaxErrors[sender.indexOfSelectedItem-1];
@@ -564,7 +597,10 @@
     self.selection = MPMakeRangePath(pathToExpression, errorRange.length);
 }
 
+
 #pragma mark - Mouse Event Handling
+
+
 - (void)mouseDown:(NSEvent *)theEvent
 {
     NSPoint pointInView = [self convertPoint:theEvent.locationInWindow
@@ -577,6 +613,7 @@
     self.selection = MPMakeRangePath(selectionPath, 0);
 }
 
+
 - (void)mouseDragged:(NSEvent *)theEvent
 {
     NSPoint pointInView = [self convertPoint:theEvent.locationInWindow
@@ -590,7 +627,10 @@
                                        newSelectionPath:mouseSelectionPath];
 }
 
+
 #pragma mark Key Event Handling
+
+
 - (void)keyDown:(NSEvent *)theEvent
 {
     NSString *characters = theEvent.characters;
@@ -617,6 +657,15 @@
     [allowedCharacters addCharactersInString:[NSString stringWithFormat:@"+-*= !%@", decimalSeparator]];
     
     if (characters.length == 1 && [characters stringByTrimmingCharactersInSet:allowedCharacters].length == 0) {
+        if ([characters isEqualTo:@"i"]) {
+            if (self.selection.location.lastIndex > 0) {
+                id<MPExpressionElement> symbol = [self.expressionStorage symbolAtIndex:self.selection.location.lastIndex-1];
+                if ([symbol isEqual:@"p"]) {
+                    self.selection = MPMakeRangePath([self.selection.location indexPathByDecrementingLastIndex], self.selection.length+1);
+                    characters = @"π";
+                }
+            }
+        }
         if ([characters isEqualToString:@"*"]) {
             characters = @"⋅";
         }
@@ -629,22 +678,28 @@
     }
 }
 
+
 #pragma mark - Actions
+
+
 - (void)switchToDegrees:(id)sender
 {
     [MPMathRules sharedRules].isUsingDegrees = YES;
 }
 
+
 - (void)switchToRadians:(id)sender
 {
     [MPMathRules sharedRules].isUsingDegrees = NO;
 }
 
+
 - (void)switchRadiansDegrees:(id)sender
 {
     [MPMathRules sharedRules].isUsingDegrees = ![MPMathRules sharedRules].isUsingDegrees;
 }
 
+
 - (IBAction)toggleFunctionsPopover:(id)sender
 {
     if (self.functionsPopover == nil || self.functionsViewController == nil) {
@@ -663,6 +718,7 @@
     }
 }
 
+
 - (void)insertFunction:(MPFunction *)function
 {
     [self.functionsPopover close];
@@ -678,8 +734,10 @@
     self.selection = MPMakeRangePath([[functionPath indexPathByAddingIndex:functionLayout.indexOfLeadingChild] indexPathByAddingIndex:0], 0);
 }
 
+
 #pragma mark Editing Actions
 
+
 - (void)insertParenthesisFunction:(id)sender
 {
     MPExpression *selectedElementsExpression = [self.expressionStorage subexpressionWithRangePath:self.selection
@@ -698,6 +756,7 @@
     self.selection = MPMakeRangePath([[functionPath indexPathByAddingIndex:0] indexPathByAddingIndex:0], self.selection.length);
 }
 
+
 - (void)insertClosingParenthesis
 {
     if (self.selection.length > 0) {
@@ -721,6 +780,7 @@
     }
 }
 
+
 - (void)insertPowerFunction
 {
     MPExpression *selectedElementsExpression = [self.expressionStorage subexpressionWithRangePath:self.selection
@@ -739,6 +799,7 @@
     self.selection = MPMakeRangePath([[functionPath indexPathByAddingIndex:0] indexPathByAddingIndex:0], self.selection.length);
 }
 
+
 - (void)insertFractionFunction
 {
     if (self.selection.length == 0) {
@@ -792,6 +853,7 @@
     }
 }
 
+
 - (void)insertNewline:(id)sender
 {
     if (self.target && self.action) {
@@ -801,6 +863,7 @@
     }
 }
 
+
 - (void)deleteBackward:(id)sender
 {
     if (self.selection.length > 0) {
@@ -853,6 +916,7 @@
     }
 }
 
+
 - (void)delete:(id)sender
 {
     [self.expressionStorage replaceItemsInRangePath:self.selection
@@ -861,8 +925,10 @@
     self.selection = MPMakeRangePath(self.selection.location, 0);
 }
 
+
 #pragma mark Selection Actions
 
+
 - (void)moveRight:(id)sender
 {
     if (self.selection.length > 0) {
@@ -875,6 +941,7 @@
     }
 }
 
+
 - (void)moveLeft:(id)sender
 {
     if (self.selection.length > 0) {
@@ -887,6 +954,7 @@
     }
 }
 
+
 - (void)moveWordRight:(id)sender
 {
     NSIndexPath *location = self.selection.maxRangePath;
@@ -896,6 +964,7 @@
     self.selection = MPMakeRangePath(newSelectionLocation, 0);
 }
 
+
 - (void)moveWordLeft:(id)sender
 {
     NSIndexPath *location = self.selection.location;
@@ -905,17 +974,20 @@
     self.selection = MPMakeRangePath(newSelectionLocation, 0);
 }
 
+
 - (void)moveToBeginningOfLine:(id)sender
 {
     self.selection = MPMakeRangePath([self.selection.location indexPathByReplacingLastIndexWithIndex:0], 0);
 }
 
+
 - (void)moveToEndOfLine:(id)sender
 {
     MPExpression *targetExpression = [self.expressionStorage elementAtIndexPath:[self.selection.location indexPathByRemovingLastIndex]];
     self.selection = MPMakeRangePath([self.selection.location indexPathByReplacingLastIndexWithIndex:targetExpression.countSymbols], 0);
 }
 
+
 - (void)moveLeftAndModifySelection:(id)sender
 {
     if (self.selection.length == 0) {
@@ -935,6 +1007,7 @@
     self.selection = [self rangePathEnclosingAnchorPath:maxLocation newSelectionPath:location];
 }
 
+
 - (void)moveRightAndModifySelection:(id)sender
 {
     if (self.selection.length == 0) {
@@ -955,6 +1028,7 @@
     self.selection = MPMakeRangePath(location, maxLocation.lastIndex-location.lastIndex);
 }
 
+
 - (void)moveWordRightAndModifySelection:(id)sender
 {
     if (self.selection.length == 0) {
@@ -977,6 +1051,7 @@
     self.selection = MPMakeRangePath(location, maxLocation.lastIndex-location.lastIndex);
 }
 
+
 - (void)moveWordLeftAndModifySelection:(id)sender
 {
     if (self.selection.length == 0) {
@@ -999,6 +1074,7 @@
     self.selection = MPMakeRangePath(location, maxLocation.lastIndex-location.lastIndex);
 }
 
+
 - (void)moveUp:(id)sender
 {
     NSIndexPath *targetExpressionPath = [self.selection.location indexPathByRemovingLastIndex];
@@ -1011,6 +1087,7 @@
     }
 }
 
+
 - (void)moveDown:(id)sender
 {
     NSIndexPath *targetExpressionPath = [self.selection.location indexPathByRemovingLastIndex];
@@ -1023,13 +1100,17 @@
     }
 }
 
+
 - (void)selectAll:(id)sender
 {
     NSIndexPath *location = [NSIndexPath indexPathWithIndex:0];
     self.selection = MPMakeRangePath(location, self.expressionStorage.countSymbols);
 }
 
+
 #pragma mark Drawing Methods
+
+
 - (void)drawRect:(NSRect)dirtyRect
 {
     // Draw the background
@@ -1066,6 +1147,7 @@
 
 #pragma mark - User Interface Validations
 
+
 - (BOOL)validateUserInterfaceItem:(id<NSValidatedUserInterfaceItem>)anItem
 {
     BOOL degrees = [MPMathRules sharedRules].isUsingDegrees;

MathKit/MPFactorialTerm.h

@@ -9,6 +9,12 @@
 #import "MPTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPFactorialTerm</code> class.
+ */
+
+
 
 @class MPFactorialTerm;
 

MathKit/MPFactorialTerm.m

@@ -8,6 +8,8 @@
 
 #import "MPFactorialTerm.h"
 
+
+
 @implementation MPFactorialTerm
 
 - (instancetype)initWithTerm:(MPTerm *)term
@@ -20,6 +22,7 @@
     return self;
 }
 
+
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
     NSDecimalNumber *value = [self.term evaluate:error];

MathKit/MPFractionFunction.h

@@ -9,6 +9,12 @@
 #import "MPFunction.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPFractionFunction</code> class.
+ */
+
+
 
 @class MPFractionFunction, MPExpression;
 

MathKit/MPFractionFunction.m

@@ -11,21 +11,26 @@
 #import "MPFractionTerm.h"
 #import "MPExpression.h"
 
+
+
 @implementation MPFractionFunction
 
 MPFunctionAccessorImplementation(NominatorExpression, _nominatorExpression)
 MPFunctionAccessorImplementation(DenominatorExpression, _denominatorExpression)
 
+
 - (NSArray *)childrenAccessors
 {
     return @[@"nominatorExpression", @"denominatorExpression"];
 }
 
+
 - (Class)functionTermClass
 {
     return [MPFractionTerm class];
 }
 
+
 - (NSString *)description
 {
     return [NSString stringWithFormat:@"%@ / %@", self.nominatorExpression, self.denominatorExpression];

MathKit/MPFractionFunctionLayout.h

@@ -9,12 +9,32 @@
 #import "MPFunctionLayout.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPFractionFunctionLayout</code> class.
+ */
+
+
 
 @class MPFractionFunctionLayout, MPFractionFunction;
 
 
+/*!
+    @class      MPFractionFunctionLayout
+    @abstract   A fraction function layout displays a <code>@link
+                //apple_ref/occ/cl/MPFractionFunction@/link</code>.
+ 
+    @discussion The nominator is displayed above the denominator. Between the two
+                children a horizontal bar is drawn.
+ */
 @interface MPFractionFunctionLayout : MPFunctionLayout
 
+/*!
+    @method     fractionFunction
+    @abstract   Returns the <code>@link
+                //apple_ref/occ/cl/MPFractionFunction@/link</code> represented by
+                the receiver.
+ */
 - (MPFractionFunction *)fractionFunction;
 
 @end

MathKit/MPFractionFunctionLayout.m

@@ -10,6 +10,7 @@
 
 #import "MPFractionFunction.h"
 
+
 #define kFractionFunctionLineWidth 1.0
 #define kFractionFunctionHorizontalInset 2.0
 #define kFractionFunctionNominatorOffset 0
@@ -17,6 +18,8 @@
 
 #define MPFractionMiddle (CTFontGetCapHeight((CTFontRef)self.font) / 2)
 
+
+
 @implementation MPFractionFunctionLayout
 
 - (MPFractionFunction *)fractionFunction
@@ -24,21 +27,25 @@
     return (MPFractionFunction *)self.function;
 }
 
+
 - (NSUInteger)indexOfChildBelowChildAtIndex:(NSUInteger)index
 {
     return 1;
 }
 
+
 - (NSUInteger)indexOfChildAboveChildAtIndex:(NSUInteger)index
 {
     return 0;
 }
 
+
 - (NSIndexSet *)indexesOfRemainingChildren
 {
     return [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, 2)];
 }
 
+
 - (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
 {
     NSRect bounds = self.bounds;
@@ -54,11 +61,13 @@
     }
 }
 
+
 - (BOOL)childAtIndexUsesSmallSize:(NSUInteger)index
 {
     return YES;
 }
 
+
 - (NSIndexPath *)indexPathForLocalMousePoint:(NSPoint)point
 {
     if (point.x < self.bounds.size.width / 2) {
@@ -68,6 +77,7 @@
     }
 }
 
+
 - (NSRect)generateBounds
 {
     NSRect nominatorBounds = [self childLayoutAtIndex:0].bounds;
@@ -80,6 +90,7 @@
     return bounds;
 }
 
+
 - (void)draw
 {
     CGFloat y = MPFractionMiddle - kFractionFunctionLineWidth / 2;

MathKit/MPFractionTerm.h

@@ -9,10 +9,24 @@
 #import "MPFunctionTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPFractionTerm</code> class.
+ */
+
+
 
 @class MPFractionTerm;
 
 
+/*!
+    @class      MPFractionTerm
+    @abstract   Represens a <code>@link
+                //apple_ref/occ/cl/MPFractionFunction@/link</code>.
+ 
+    @discussion A fraction is evaluating by dividing the nominator by the
+                denominator.
+ */
 @interface MPFractionTerm : MPFunctionTerm
 
 @end

MathKit/MPFractionTerm.m

@@ -10,6 +10,8 @@
 
 #import "MPParsedExpression.h"
 
+
+
 @implementation MPFractionTerm
 
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error

MathKit/MPFunction+MPToken.h

@@ -10,6 +10,12 @@
 #import "MPToken.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPFunction(MPToken) category</code>.
+ */
+
+
 
 /*!
     @category   MPFunction (MPToken)

MathKit/MPFunction.h

@@ -11,6 +11,8 @@
 
 /*!
  @header
+ This file contains the <code>MPFunction</code> class.
+ 
  <code>MPFunction</code> is a half abstract class that is designed to be
  subclassed. Subclasses of the <code>MPFunction</code> class (subsequently called
  <i>functions</i>) need to regard the following guidelines:
@@ -41,7 +43,6 @@
  */
 
 
-
 /*!
     @define     MPFunctionAccessorImplementation
     @abstract   This macro implements the setter of a previously declared

MathKit/MPFunction.m

@@ -18,7 +18,6 @@
 
 @implementation MPFunction
 
-
 #pragma mark Creation Methods
 
 

MathKit/MPFunctionLayout.h

@@ -9,53 +9,334 @@
 #import "MPLayout.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPFunctionLayout</code> class.
+ 
+ The <code>MPFunctionLayout</code> class is an abstract class that implements
+ many of the methods from the layout system. Concrete subclasses implement the
+ actual layout of a specific function and its children. For that reason
+ <code>MPFunctionLayout</code> features a private cache. In that cache any
+ subclass can store objects so they do not need to be recreated everytime the
+ function is rendered.
+ */
+
+
 
 @class MPFunctionLayout, MPFunction, MPExpressionLayout;
 
 
+/*!
+    @class      MPFunctionLayout
+    @abstract   A function layout represents a <code>@link
+                //apple_ref/occ/cl/MPFunction@/link</code>.
+ 
+    @discussion <code>MPFunctionLayout</code> is an abstract class that
+                implements many required methods of the layout system. For more
+                information about the layout system see the documentation on the
+                <code>@link //apple_ref/occ/cl/MPLayout@/link</code> class.
+ */
 @interface MPFunctionLayout : MPLayout
 
+/*!
+    @method     functionLayoutForFunction:parent:
+    @abstract   Creates a function layout that can draw the specified function.
+ 
+    @discussion This method is the preferred whay to construct function layouts.
+ 
+    @param      function
+                The function to create a layout for. Must not be
+                <code>nil</code>.
+ 
+    @param      parent
+                The parent of the created function layout. May be
+                <code>nil</code>.
+ 
+    @return     A newly created function layout.
+ */
 + (MPFunctionLayout *)functionLayoutForFunction:(MPFunction *)function
                                          parent:(MPExpressionLayout *)parent;
 
-@property (readonly, nonatomic, weak) MPFunction *function;
 
-@end
+/*!
+    @method     initWithFunction:parent:
+    @abstract   Initializes the receiver with the specified function and parent.
  
-@interface MPFunctionLayout (MPSubclassOverride)
+    @discussion This method should not be called direcly. It is however possible
+                do perform custom initialization in sublcasses by overriding this method.
  
+                This method is the designated initializer of the
+                <code>MPFunctionLayout</code> class.
+
+    @param      function
+                The function represented by the receiver. Must not be
+                <code>nil</code>.
+ 
+    @param      parent
+                The parent of the receiver or <code>nil</code> if it does not
+                have one.
+ 
+    @return     A newly initialized <code>MPFunctionLayout</code> instance.
+ */
 - (instancetype)initWithFunction:(MPFunction *)function
                           parent:(MPExpressionLayout *)parent;
 
-#pragma mark Cache Methods
+
+/*!
+    @property   function
+    @abstract   The function represented by the receiver.
+ */
+@property (readonly, nonatomic, weak) MPFunction *function;
+
+
+/*!
+    @method     lineForPrivateCacheIndex:generator:
+    @abstract   Returns the cached line for the specified private index.
+ 
+    @discussion This is a convenience method that calls <code>@link
+                //apple_ref/occ/instm/MPFunctionLayout/objectForPrivateCacheIndex:generator:@/link</code>.
+                See the documentation on that method for details.
+ 
+    @param      index
+                The index of the line to retrieve. Private cache indexes start at <code>0</code>.
+ 
+    @param      generator
+                A block that generates a line in case there is no cached one.
+ 
+    @return     The cached line or the newly generated one if there was no cache value.
+ */
 - (CTLineRef)lineForPrivateCacheIndex:(NSUInteger)index
                             generator:(CTLineRef (^)())generator;
+
+
+/*!
+    @method     objectForPrivateCacheIndex:generator:
+    @abstract   Returns the cached value for the specified private index.
+ 
+    @discussion If there is no object in the private cache for the specified
+                index the specified <code>generator</code> is invoked. The result
+                of the <code>generator</code> is then stored at the specified
+                <code>index</code> and returned.
+ 
+    @param      index
+                The index of the private cache item to retrieve. Private cache
+                indexes start at <code>0</code>.
+
+    @param      generator
+                A block that generates an object in case there is no cached one.
+ 
+    @return     The cached object or the newly generated one if there was no
+                cache value.
+ */
 - (id)objectForPrivateCacheIndex:(NSUInteger)index
                        generator:(id (^)())generator;
 
-// Should also implement accessor method for special function type:
-// - (MPCustomFunction *)customFunction
-// {
-//      return (MPCustomFunction *)self.function;
-// }
+@end
 
-#pragma mark Size and Drawing Methods
+
+
+/*!
+    @category   MPFunctionLayout (MPSubclassOverride)
+    @abstract   The methods defined in this category must be implemented by any
+                concrete subclass of <code>MPFunctionLayout</code>.
+ */
+@interface MPFunctionLayout (MPSubclassOverride)
+
+/* Apart from the methods below it is recommended (although not required) to
+ * implement a method in the following form:
+ * - (CustomFunctionType *)customFunction
+ * {
+ *     return (CustomFunctionType *)self.function;
+ * }
+ */
+
+
+/*!
+    @method     childAtIndexUsesSmallSize:
+    @abstract   Determines whether the child expression at the specified index
+                should be drawn using the small font.
+ 
+    @discussion This method may be overridden to change the default behaviour.
+ 
+    @param      index
+                The index of the child whose size is to be determined.
+
+    @return     <code>YES</code> if the receiver's child at the specified
+                <code>index</code> should use the small font, <code>NO</code>
+                otherwise. The default implementation returns <code>NO</code>.
+ */
 - (BOOL)childAtIndexUsesSmallSize:(NSUInteger)index; // May be implemented
-- (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index; // To be implemented
-- (NSIndexPath *)indexPathForMousePoint:(NSPoint)point;
-- (NSIndexPath *)indexPathForLocalMousePoint:(NSPoint)point; // To be implemented
-- (NSRect)generateBounds; // To be implemented
-- (void)draw; // To be implemented
 
-// Specify the child that is used when the cursor enters the function from the left or right respectively
-- (NSUInteger)indexOfLeadingChild; // To be implemented
-- (NSUInteger)indexOfTrailingChild; // To be implemented
 
-// The index of the child before (left) or after (right) the child at @c index. return NSNotFound if there is no child before or after @c index.
-- (NSUInteger)indexOfChildBeforeChildAtIndex:(NSUInteger)index; // May be implemented
-- (NSUInteger)indexOfChildAfterChildAtIndex:(NSUInteger)index; // May be implemented
-- (NSUInteger)indexOfChildBelowChildAtIndex:(NSUInteger)index; // May be implemented
-- (NSUInteger)indexOfChildAboveChildAtIndex:(NSUInteger)index; // May be implemented
-- (NSIndexSet *)indexesOfRemainingChildren; // May be implemented
+/*!
+    @method     offsetOfChildLayoutAtIndex:
+    @abstract   Implementation requirement from superclass. See <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/offsetOfChildLayoutAtIndex:@/link</code>
+                for details.
+ */
+- (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index;
+
+
+/*!
+    @method     indexPathForLocalMousePoint:
+    @abstract   Performs hit testing.
+ 
+    @discussion This method is called when the user selected a point in a
+                function that is not in any of its children. The return value of
+                this method identifies the position relative to the function
+                represented by the receiver where the caret is to be placed.
+ 
+                This method must be implemented by subclasses.
+ 
+    @param      point
+                The location the user clicked at relative to the receiver.
+ 
+    @return     An index path identifying the new caret position relative to the
+                function represented by the receiver. Use an index path
+                containing a single index to place the caret before or after the
+                represented function (<code>0</code> means before, <code>1</code>
+                means after).
+ */
+- (NSIndexPath *)indexPathForLocalMousePoint:(NSPoint)point;
+
+
+/*!
+    @method     generateBounds
+    @abstract   Implementation requirement from superclass. See <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/generateBounds@/link</code>
+                for details.
+ */
+- (NSRect)generateBounds;
+
+
+/*!
+    @method     draw
+    @abstract   Implementation requirement from superclass. See <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/draw@/link</code>
+                for details.
+ */
+- (void)draw;
+
+
+/*!
+    @method     indexOfLeadingChild
+    @abstract   Identifies the index of the receiver's child that will get
+                selected when the cursor <i>enters</i> the function in the
+                direction of reading.
+ 
+    @discussion You may implement this method do override the default behaviour.
+ 
+    @return     The index of the leading child. The default implementation
+                returns <code>0</code>.
+ */
+- (NSUInteger)indexOfLeadingChild;
+
+
+/*!
+    @method     indexOfTrailingChild
+    @abstract   Identifies the index of the receiver's child that will get
+                selected when the cursor <i>enters</i> the function in the
+                direction opposite to reading.
+ 
+    @discussion You may implement this method do override the default behaviour.
+ 
+    @return     The index of the trailing child. The default implementation
+                returns <code>0</code>.
+ */
+- (NSUInteger)indexOfTrailingChild;
+
+
+/*!
+    @method     indexOfChildBeforeChildAtIndex:
+    @abstract   Identifies the index of the receiver's child that will get
+                selected when the cursor <i>leaves</i> the child at the specified
+                index in the direction opposite to reading.
+ 
+    @discussion Return <code>NSNotFound</code> from this method if the function
+                should be <i>left</i> when the child at the specified index is
+                <i>left</i>.
+ 
+                You may implement this method to override the default behaviour.
+ 
+    @param      index
+                The index of the child the caret <i>left</i>.
+ 
+    @return     The index of the child that is to be <i>entered</i> or
+                <code>NSNotFound</code> if there are no more children. The
+                default implementation returns <code>NSNotFound</code>.
+ */
+- (NSUInteger)indexOfChildBeforeChildAtIndex:(NSUInteger)index;
+
+
+/*!
+    @method     indexOfChildAfterChildAtIndex:
+    @abstract   Identifies the index of the receiver's child that will get
+                selected when the cursor <i>leaves</i> the child at the specified
+                index in the direction of reading.
+ 
+    @discussion Return <code>NSNotFound</code> from this method if the function
+                should be <i>left</i> when the child at the specified index is
+                <i>left</i>.
+ 
+                You may implement this method to override the default behaviour.
+ 
+    @param      index
+                The index of the child the caret <i>left</i>.
+ 
+    @return     The index of the child that is to be <i>entered</i> or
+                <code>NSNotFound</code> if there are no more children.
+ */
+- (NSUInteger)indexOfChildAfterChildAtIndex:(NSUInteger)index;
+
+
+/*!
+    @method     indexOfChildBelowChildAtIndex:
+    @abstract   Returns the index of the child that is graphically positioned
+                below the child at the specified index.
+ 
+    @discussion If there are no other children below the one at the specified
+                index this method should return <code>index</code>.
+ 
+                You may implement this method to override the default behaviour.
+ 
+    @param      index
+                The index of the child whose neighbor is to be determined.
+ 
+    @return     The index of the child directly below the one at the specified
+                index. The default implementation returns <code>index</code>.
+ */
+- (NSUInteger)indexOfChildBelowChildAtIndex:(NSUInteger)index;
+
+
+/*!
+    @method     indexOfChildAboveChildAtIndex:
+    @abstract   Returns the index of the child that is graphically positioned
+                above the child at the specified index.
+ 
+    @discussion If there are no other children above the one at the specified
+                index this method should return <code>index</code>.
+ 
+                You may implement this method to override the default behaviour.
+ 
+    @param      index
+                The index of the child whose neighbor is to be determined.
+ 
+    @return     The index of the child directly above the one at the specified
+                index. The default implementation returns <code>index</code>.
+ */
+- (NSUInteger)indexOfChildAboveChildAtIndex:(NSUInteger)index;
+
+
+/*!
+    @method     indexesOfRemainingChildren
+    @abstract   Returns the indexes of the receiver's children that should
+                replace the receiver if it is deleted.
+ 
+    @discussion You may implement this method to override the default behaviour.
+ 
+    @return     The indexes of the children that replace the receiver when it is
+                deleted. The default implementation returns an empty index set.
+ */
+- (NSIndexSet *)indexesOfRemainingChildren;
 
 @end

MathKit/MPFunctionLayout.m

@@ -8,24 +8,28 @@
 
 #import "MPFunctionLayout.h"
 
-#import "MPExpression.h"
+#import "MPExpressionLayout.h"
+
 #import "MPFunction.h"
-#import "MPSumFunction.h"
+#import "MPFractionFunction.h"
 #import "MPParenthesisFunction.h"
 #import "MPPowerFunction.h"
-#import "MPFractionFunction.h"
+#import "MPSumFunction.h"
 
-#import "MPExpressionLayout.h"
-#import "MPSumFunctionLayout.h"
+#import "MPFractionFunctionLayout.h"
 #import "MPParenthesisFunctionLayout.h"
 #import "MPPowerFunctionLayout.h"
-#import "MPFractionFunctionLayout.h"
+#import "MPSumFunctionLayout.h"
 
 #import "NSIndexPath+MPAdditions.h"
 
+
+
 @implementation MPFunctionLayout
 
 #pragma mark Creation Methods
+
+
 + (MPFunctionLayout *)functionLayoutForFunction:(MPFunction *)function
                                          parent:(MPExpressionLayout *)parent
 {
@@ -43,6 +47,7 @@
                                    parent:parent];
 }
 
+
 - (instancetype)initWithFunction:(MPFunction *)function
                           parent:(MPExpressionLayout *)parent
 {
@@ -53,7 +58,9 @@
     return self;
 }
 
+
 #pragma mark Cache Methods
+
 - (CTLineRef)lineForPrivateCacheIndex:(NSUInteger)index
                             generator:(CTLineRef (^)())generator
 {
@@ -67,6 +74,7 @@
     return (__bridge CTLineRef)(lineObject);
 }
 
+
 - (id)objectForPrivateCacheIndex:(NSUInteger)index
                        generator:(id (^)())generator
 {
@@ -74,11 +82,13 @@
     return [self cachableObjectForIndex:actualIndex generator:generator];
 }
 
+
 - (NSUInteger)numberOfChildren
 {
     return self.function.numberOfChildren;
 }
 
+
 - (MPLayout *)childLayoutAtIndex:(NSUInteger)index
 {
     return [self cachableObjectForIndex:index generator:^id{
@@ -91,11 +101,13 @@
     }];
 }
 
+
 - (BOOL)childAtIndexUsesSmallSize:(NSUInteger)index
 {
     return NO;
 }
 
+
 - (NSIndexPath *)indexPathForMousePoint:(NSPoint)point
 {
     // A single index is used to communicate back wether the
@@ -116,36 +128,43 @@
     return [self indexPathForLocalMousePoint:point];
 }
 
+
 - (NSUInteger)indexOfLeadingChild
 {
     return 0;
 }
 
+
 - (NSUInteger)indexOfTrailingChild
 {
     return 0;
 }
 
+
 - (NSUInteger)indexOfChildBeforeChildAtIndex:(NSUInteger)index
 {
     return NSNotFound;
 }
 
+
 - (NSUInteger)indexOfChildAfterChildAtIndex:(NSUInteger)index
 {
     return NSNotFound;
 }
 
+
 - (NSUInteger)indexOfChildBelowChildAtIndex:(NSUInteger)index
 {
     return index;
 }
 
+
 - (NSUInteger)indexOfChildAboveChildAtIndex:(NSUInteger)index
 {
     return index;
 }
 
+
 - (NSIndexSet *)indexesOfRemainingChildren
 {
     return [NSIndexSet indexSet];

MathKit/MPFunctionTerm.h

@@ -8,6 +8,28 @@
 
 #import "MPTerm.h"
 
+/*!
+ @header
+ This file contains the <code>MPFunctionTerm</code> class.
+ */
+
+
+/*!
+    @define     MPEvaluateExpression
+    @abstract   Evaluates the receiver's child at the specified index and assigns
+                the evaluation result to a variable.
+ 
+    @discussion If errors occur during evaluation this macro returns
+                <code>nil</code>. Also there has to exist a <code>NSError *__autoreleasing *</code> pointer called <code>error</code>.
+ 
+    @param      var
+                The name of the variable that will be declared in this macro. It
+                will be of the type <code>NSDecimalNumber *</code> and contain
+                the result of the evaluation.
+ 
+    @param      index
+                The index of the child to be evaluated.
+ */
 #define MPEvaluateExpression(var, index) NSDecimalNumber *var = [[self expressionAtIndex:index] evaluate:error]; if (var == nil) return nil
 
 
@@ -15,11 +37,62 @@
 @class MPFunctionTerm, MPFunction, MPParsedExpression;
 
 
+/*!
+    @class      MPFunctionTerm
+    @abstract   A function term represents the term of a generic function.
+ 
+    @discussion This class is an abstract class that can not be evaluated. It is
+                the common superclass of all terms that represent <code>@link
+                //apple_ref/occ/cl/MPFunction@/link</code> instances.
+ */
 @interface MPFunctionTerm : MPTerm
 
+/*!
+    @method     initWithFunction:errors:
+    @abstract   Initializes a <code>MPFunctionTerm</code> from the specified
+                <code>@link //apple_ref/occ/cl/MPFunction@/link</code> instance.
+ 
+    @discussion This method parses the children of the specified
+                <code>function</code> and stores the respective parsed
+                expressions. They are accessible using the <code>@link
+                //apple_ref/occ/instm/MPFunctionTerm/expressionAtIndex:@/link</code>
+                method.
+ 
+                Whether the children should contain a variable definition is
+                determined using the <code>@link
+                //apple_ref/occ/instm/MPFunction/expectsVariableDefinitionInChildAtIndex:@/link</code>
+
+    @param      function
+                The function to initialize the receiver with. This method parses
+                the function's children. If any of them contain syntax errors
+                they are returned indirectly through the <code>errors</code>
+                parameter.
+ 
+    @param      errors
+                If any of the <code>function</code>'s children contain syntax
+                errors they are returned indirectly through this parameter. In
+                that case the method returns <code>nil</code>. If there are no
+                errors the parameter is not modified. This parameter is never set
+                to an empty array.
+ 
+    @return     A new <code>MPFunctionTerm</code> instance.
+ */
 - (instancetype)initWithFunction:(MPFunction *)function
                           errors:(NSArray *__autoreleasing *)errors; /* designated initializer */
 
+
+/*!
+    @method     expressionAtIndex:
+    @abstract   Returns a <code>@link
+                //apple_ref/occ/cl/MPParsedExpression@/link</code> instance that
+                represents the child at <code>anIndex</code> of the function that
+                is represented by the receiver.
+ 
+    @param      anIndex
+                The index of the child.
+ 
+    @return     A parsed expression that represents th
+ */
 - (MPParsedExpression *)expressionAtIndex:(NSUInteger)anIndex;
 
 @end

MathKit/MPFunctionTerm.m

@@ -9,10 +9,6 @@
 #import "MPFunctionTerm.h"
 
 #import "MPFunction.h"
-#import "MPExpression.h"
-#import "MPParsedExpression.h"
-
-#import "MPToken.h"
 
 
 
@@ -64,6 +60,7 @@
     return self;
 }
 
+
 - (MPParsedExpression *)expressionAtIndex:(NSUInteger)anIndex
 {
     return [self.parsedExpressions objectAtIndex:anIndex];

MathKit/MPFunctionsViewController.h

@@ -7,19 +7,74 @@
 //
 
 
+/*!
+ @header
+ This file contains the <code>MPFunctionsViewController</code> class.
+ */
+
+
 
 @class MPFunctionsViewController, MPFunctionsCollectionView;
 
 
+/*!
+    @class      MPFunctionsViewController
+    @abstract   Controls a view from which the user can select function to be
+                inserted into a <code>@link
+                //apple_ref/occ/cl/MPExpressionView@/link</code>.
+ 
+    @discussion The view contain a <code>NSCollectionView</code> displaying the
+                prototypes an a <code>NSTextField</code> displaying a description
+                of the currently selected prototype.
+ */
 @interface MPFunctionsViewController : NSViewController
 
-- (id)init;
+/*!
+    @property   collectionView
+    @abstract   The <code>NSCollectionView</code> that displays the function
+                prototypes.
+ */
+@property (weak) IBOutlet NSCollectionView *collectionView;
 
-@property (weak) IBOutlet MPFunctionsCollectionView *collectionView;
+
+/*!
+    @property   functionPrototypes
+    @abstract   Contains the <code>@link
+                //apple_ref/occ/cl/MPFunction@/link</code> objects that get
+                inserted into an expression if selected.
+ 
+    @discussion Every object in the array must be an <code>@link
+                //apple_ref/occ/cl/MPFunction@/link</code> instance.
+ */
 @property (nonatomic, strong) NSArray *functionPrototypes;
+
+
+/*!
+    @property   currentDescription
+    @abstract   The string that describes the function prototype that is
+                currently selected.
+ 
+    @discussion If this string is empty a placeholder value will be displayed.
+ */
 @property (nonatomic, strong) NSString *currentDescription;
 
+
+/*!
+    @property   target
+    @abstract   The target object to receive action messages from the receiver.
+ */
 @property (nonatomic, weak) id target;
-@property (nonatomic) SEL action; // 1 argument: The function to insert
+
+
+/*!
+    @property   action
+    @abstract   The receiver's action method to the specified selector.
+ 
+    @discussion The action method is invoked when the user selects one of the 
+                function prototypes in the collection view. The prototype that
+                was selected is passed as the one and only argument to
+                the specified selector.
+ */
+@property (nonatomic) SEL action;
 
 @end

MathKit/MPFunctionsViewController.m

@@ -8,18 +8,21 @@
 
 #import "MPFunctionsViewController.h"
 
-#import "MPExpression.h"
-#import "NSString+MPExpressionElement.h"
 #import "MPFunction.h"
-#import "MPSumFunction.h"
+#import "MPFractionFunction.h"
 #import "MPParenthesisFunction.h"
 #import "MPPowerFunction.h"
-#import "MPFractionFunction.h"
+#import "MPSumFunction.h"
 
 #import "MPFunctionLayout.h"
 
+#import "NSString+MPExpressionElement.h"
+
+
+
 @class MPFunctionsCollectionView, MPFunctionTemplateView, MPFunctionTemplateItem;
 
+
 @interface MPFunctionsCollectionView : NSCollectionView
 
 @property (nonatomic, weak) MPFunctionTemplateItem *hoverItem;
@@ -30,6 +33,7 @@
 @end
 
 
+
 @interface MPFunctionTemplateView : NSView
 
 @property (nonatomic, strong) MPFunction *functionTemplate;
@@ -42,16 +46,20 @@
 
 
 @interface MPFunctionTemplateItem : NSCollectionViewItem
+
 @property (nonatomic, copy) NSString *templateName;
+
 @end
 
 
+
 @implementation MPFunctionsCollectionView
 
 - (void)mouseDown:(NSEvent *)theEvent
 {
 }
 
+
 - (void)mouseUp:(NSEvent *)theEvent
 {
     NSPoint pointInView = [self convertPoint:theEvent.locationInWindow
@@ -87,25 +95,30 @@
     [super updateTrackingAreas];
 }
 
+
 - (void)mouseEntered:(NSEvent *)theEvent
 {
     self.mouseOver = YES;
     self.needsDisplay = YES;
 }
 
+
 - (void)mouseExited:(NSEvent *)theEvent
 {
     self.mouseOver = NO;
     self.needsDisplay = YES;
 }
 
+
 - (void)setFunctionTemplate:(MPFunction *)functionTemplate
 {
     _functionTemplate = functionTemplate;
     _functionTemplateLayout = nil;
 }
 
+
 @synthesize functionTemplateLayout = _functionTemplateLayout;
+
 - (MPFunctionLayout *)functionTemplateLayout
 {
     
@@ -117,16 +130,19 @@
     return _functionTemplateLayout;
 }
 
+
 - (NSSize)intrinsicContentSize
 {
     return [self.functionTemplateLayout bounds].size;
 }
 
+
 - (BOOL)isOpaque
 {
     return NO;
 }
 
+
 - (void)drawRect:(NSRect)dirtyRect
 {
     if (self.mouseOver) {
@@ -150,11 +166,13 @@
 
 static void *MPFunctionTemplateViewMouseOverContext = @"MPFunctionTemplateViewMouseOverContext";
 
+
 - (id)awakeAfterUsingCoder:(NSCoder *)aDecoder
 {
     return [super awakeAfterUsingCoder:aDecoder];
 }
 
+
 - (void)observeValueForKeyPath:(NSString *)keyPath
                       ofObject:(id)object
                         change:(NSDictionary *)change
@@ -171,6 +189,7 @@ static void *MPFunctionTemplateViewMouseOverContext = @"MPFunctionTemplateViewMo
     }
 }
 
+
 - (void)setRepresentedObject:(id)representedObject
 {
     MPFunctionTemplateView *view = (MPFunctionTemplateView *)self.view;
@@ -191,6 +210,8 @@ static void *MPFunctionTemplateViewMouseOverContext = @"MPFunctionTemplateViewMo
 
 @end
 
+
+
 @implementation MPFunctionsViewController
 
 - (id)init
@@ -199,6 +220,7 @@ static void *MPFunctionTemplateViewMouseOverContext = @"MPFunctionTemplateViewMo
                           bundle:[NSBundle bundleForClass:[self class]]];
 }
 
+
 - (void)awakeFromNib
 {
     MPFunction *sumFunction = [[MPSumFunction alloc] init];
@@ -227,40 +249,45 @@ static void *MPFunctionTemplateViewMouseOverContext = @"MPFunctionTemplateViewMo
                           forKeyPath:@"hoverItem"
                              options:0
                              context:MPCollectionViewHoverItemChangeContext];
-    self.collectionView.target = self.target;
-    self.collectionView.action = self.action;
+    ((MPFunctionsCollectionView *)self.collectionView).target = self.target;
+    ((MPFunctionsCollectionView *)self.collectionView).action = self.action;
 }
 
+
 static void *MPCollectionViewHoverItemChangeContext = @"MPCollectionViewHoverItemChangeContext";
 
+
 - (void)setView:(NSView *)view
 {
     [super setView:view];
 }
 
+
 - (void)setTarget:(id)target
 {
     _target = target;
     if (self.collectionView) {
-        self.collectionView.target = target;
+        ((MPFunctionsCollectionView *)self.collectionView).target = target;
     }
 }
 
+
 - (void)setAction:(SEL)action
 {
     _action = action;
     if (self.collectionView) {
-        self.collectionView.action = action;
+        ((MPFunctionsCollectionView *)self.collectionView).action = action;
     }
 }
 
+
 - (void)observeValueForKeyPath:(NSString *)keyPath
                       ofObject:(id)object
                         change:(NSDictionary *)change
                        context:(void *)context
 {
     if (context == MPCollectionViewHoverItemChangeContext) {
-        self.currentDescription = self.collectionView.hoverItem.templateName;
+        self.currentDescription = ((MPFunctionsCollectionView *)self.collectionView).hoverItem.templateName;
     } else {
         [super observeValueForKeyPath:keyPath
                              ofObject:object

MathKit/MPLayout.h

@@ -6,12 +6,82 @@
 //  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
 //
 
+
+/*!
+ @header
+ This file contains the <code>MPLayout</code> class.
+ 
+ The <code>MPLayout</code> class renders an expression to be displayed in an
+ <code>@link //apple_ref/occ/cl/MPExpressionView@/link</code>. There are multiple
+ subclasses of <code>MPLayout</code> the most important of which are <code>@link
+ //apple_ref/occ/cl/MPExpressionLayout@/link</code> and <code>@link
+ //apple_ref/occ/cl/MPFunctionLayout@/link</code> for rendering expressions and
+ functions respectively.
+ 
+ Both types of layouts can occur in two different sizes: normal and small. The
+ root expression ueses the normal size. Depending on the concrete subclass of
+ <code>@link //apple_ref/occ/cl/MPFunctionLayout@/link</code> that is used a
+ function's children (and any subsequent children) may be rendered using the
+ small size. Also there are two different fonts available for layouts: a normal
+ and a special font. The special font should only be used to emphasize special
+ content that uses the normal font.
+ 
+ If an expression is empty an empty box is rendered instead. That box (called the
+ <i>empty box</i> uses the font metrics of the empty expression it represents.
+ That means it uses different sizes depending on whether the expression uses a
+ small or normal sized font. Also it is drawn a little smaller than the actual
+ box's height is because it looks nicer. Depending on your needs you can query
+ the metrics of the empty box using the <code>kMPEmptyBox...</code> or
+ <code>kMPEmptyBoxDrawing...</code> macros. These macros must not be used outside
+ of the <code>MPLayout</code> class or any of it subclasses.
+ */
+
+
+/*!
+    @define     kMPEmptyBoxWidth
+    @abstract   The width of the empty box.
+ */
 #define kMPEmptyBoxWidth (self.usesSmallSize ? 2.0 : 3.0)
+
+
+/*!
+    @define     kMPEmptyBoxHeight
+    @abstract   The actual height of the empty box.
+ */
 #define kMPEmptyBoxHeight (CTFontGetDescent((CTFontRef)self.font) + CTFontGetAscent((CTFontRef)self.font) + CTFontGetLeading((CTFontRef)self.font))
+
+
+/*!
+    @define     kMPEmptyBoxYOrigin
+    @abstract   The actual vertical origin of the empty box.
+ 
+    @discussion The vertical origin is a negative value to be compliant with the
+                metrics of strings.
+ */
 #define kMPEmptyBoxYOrigin (-(CTFontGetDescent((CTFontRef)self.font) + CTFontGetLeading((CTFontRef)self.font)))
 
+
+/*!
+    @define     kMPEmptyBoxDrawingWidth
+    @abstract   The with the empty box is rendered with.
+ */
 #define kMPEmptyBoxDrawingWidth kMPEmptyBoxWidth
+
+
+/*!
+    @define     kMPEmptyBoxDrawingHeight
+    @abstract   The height the empty box is drawn with.
+ */
 #define kMPEmptyBoxDrawingHeight (CTFontGetDescent((CTFontRef)self.font) + CTFontGetAscent((CTFontRef)self.font))
+
+
+/*!
+    @define     kMPEmptyBoxDrawingYOrigin
+    @abstract   The vertical origin the empty box is drawn at.
+ 
+    @discussion The vertical origin is a negative value to be compliant with the
+                metrics of strings.
+ */
 #define kMPEmptyBoxDrawingYOrigin (-(CTFontGetDescent((CTFontRef)self.font) + CTFontGetLeading((CTFontRef)self.font)/2))
 
 
@@ -19,58 +89,548 @@
 @class MPLayout, MPRangePath;
 
 
+/*!
+    @class      MPLayout
+    @abstract   This is an abstract class that defines the basic methods that
+                must be implemented by other layout classes. It also defines some
+                useful helper methods.
+ 
+    @discussion The <code>MPLayout</code> class maintains a generic cache. It is
+                used to store child layouts and actual cache information.
+ 
+                Every layout instance represents either an expression or a
+                function. The instance's children represent the children of the
+                represented object.
+ */
 @interface MPLayout : NSObject
 
 #pragma mark Creation Methods
+/*!
+ @methodgroup Creation Methods
+ */
+
+
+/*!
+    @method     init
+    @abstract   Initializes the receiver.
+ 
+    @discussion This method should only be used to initialize the expression
+                layout that renders the root layout.
+
+                This method is the designated initializer of the
+                <code>MPLayout</code> class.
+ 
+    @return     A newly initialized <code>MPLayout</code> instance.
+ */
 - (instancetype)init;
+
+
+/*!
+    @method     initWithParent:
+    @abstract   Initializes the receiver with the specified parent.
+ 
+    @discussion This method should generally be used when initializing layout
+                instances. In most cases it should be called at some point in the
+                implementation of the <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/childLayoutAtIndex:@/link</code>
+                method.
+ 
+    @param      parent
+                The receiver's parent.
+ 
+    @return     A newly initialized <code>MPLayout</code> instance.
+ */
 - (instancetype)initWithParent:(MPLayout *)parent;
 
-#pragma mark Properties
-- (NSFont *)normalFontWithSize:(CGFloat)size;
-- (NSFont *)specialFontWithSize:(CGFloat)size;
-- (CGFloat)contextInferredFontSize;
-- (CGFloat)normalFontSize;
-- (CGFloat)smallFontSize;
 
+#pragma mark Properties
+/*!
+ @methodgroup Properties
+ */
+
+
+/*!
+    @method     font
+    @abstract   Returns the receiver's context inferred font.
+ 
+    @discussion The context inferred font is the normal font using the context
+                inferred font size. Normally this method is used for any textual
+                content of a layout.
+
+    @return     The font the receiver should use for rendering textual content.
+ */
 - (NSFont *)font;
 
+
+/*!
+    @method     normalFontWithSize:
+    @abstract   Returns a <code>NSFont</code> object that represents the normal
+                font in the specified <code>size</code>.
+ 
+    @discussion Instead of this method you want to use <code>@link
+                //apple_ref/occ/instm/MPLayout/font@/link</code> instead in most
+                cases.
+ 
+    @param      size
+                The size of the font.
+ 
+    @return     A <code>NSFont</code> object that can be used to render textual
+                content of the receiver in the specified <code>size</code>.
+ */
+- (NSFont *)normalFontWithSize:(CGFloat)size;
+
+
+/*!
+    @method     specialFontWithSize:
+    @abstract   Returns a <code>NSFont</code> object that represents the special
+                font in the specified <code>size</code>.
+ 
+    @discussion Use fonts returned by this method only if you need to emphasize
+                text that is surrounded by other text that uses the normal font.
+ 
+    @param      size
+                The size of the font.
+ 
+    @return     A <code>NSFont</code> object that can be used to render special
+                textual content of the receiver in the specified
+                <code>size</code>.
+ */
+- (NSFont *)specialFontWithSize:(CGFloat)size;
+
+
+/*!
+    @method     contextInferredFontSize
+    @abstract   Returns the appropriate font size for the receiver based on the
+                context it will be rendered in.
+ */
+- (CGFloat)contextInferredFontSize;
+
+
+/*!
+    @method     normalFontSize
+    @abstract   Returns the font size that is used in the root expression.
+ */
+- (CGFloat)normalFontSize;
+
+
+/*!
+    @method     smallFontSize
+    @abstract   Returns the font size that is used in expressions that are using
+                the small size.
+ */
+- (CGFloat)smallFontSize;
+
+
 #pragma mark Cache Tree
+/*!
+ @methodgroup Cache Tree
+ */
+
+
+/*!
+    @property   parent
+    @abstract   The receiver's parent layout.
+ 
+    @discussion The parent layout is most likely the one that created the
+                receiver and is responsible for setting its attributes
+                appropriately based on the rendering context.
+ */
 @property (readonly, nonatomic, weak) MPLayout *parent;
 
+
 #pragma mark Cache Methods
-// Querying Caches
+/*!
+ @methodgroup Cache Methods
+ */
+
+
+/*!
+    @method     chacableObjectForIndex:generator:
+    @abstract   Returns the cached object for the specified <code>index</code> or
+                creates one if it does not exist.
+ 
+    @discussion This method only returns <code>nil</code> if the
+                <code>generator</code> returns <code>nil</code>.
+ 
+    @param      index
+                The index of the cached object to retrieve.
+ 
+    @param      generator
+                This block is executed if there is no cached object at
+                <code>index</code>. The result of this block is then cached at
+                the <code>index</code>.
+ 
+    @return     The cached object for <code>index</code> or the result of the
+                <code>generator</code> if there is no cached object.
+ */
 - (id)cachableObjectForIndex:(NSUInteger)index
                    generator:(id(^)())generator;
 
-// Clearing Caches
+
+/*!
+    @method     clearCacheInRange:replacementLength:
+    @abstract   Removes the objects in the specified from the cache and moves all
+                objects at subsequent indexes.
+ 
+    @discussion The objects at subsequent indexes are moved
+                <code>replacementLength - range.length</code> places. If
+                <code>replacementLength</code> is greater than
+                <code>range.length</code> they are moved to smaller indexes.
+ 
+    @param      range
+                The range of objects to be removed.
+ 
+    @param      replacementLength
+                The number of indexes replacing the ones specified by
+                <code>range</code>.
+ */
 - (void)clearCacheInRange:(NSRange)range
         replacementLength:(NSUInteger)replacementLength;
+
+
+/*!
+    @method     invalidate
+    @abstract   Invalidates the receiver.
+ 
+    @discussion Invalidating the receiver causes him to discard all cached
+                information about itself and send a <code>invalidate</code>
+                message to its parent. The cached information about the
+                receiver's children is <b>not</b> discarded. Use <code>@link
+                //apple_ref/occ/instm/MPLayout/clearCacheInRange:replacementLength:@/link</code>
+                for that purpose.
+ */
 - (void)invalidate;
 
+
+/*!
+    @method     childLayoutAtIndexPath:
+    @abstract   Returns the child layout at the specified index path.
+ 
+    @discussion If the <code>indexPath</code> is empty the receiver is returned.
+                If the child layout the index path specifies is not yet created
+                this method should do so and add it to the cache of the
+                respective parent layout.
+ 
+    @param      indexPath
+                The index path of the child.
+ 
+    @return     The child at the specified index path.
+ */
 - (MPLayout *)childLayoutAtIndexPath:(NSIndexPath *)indexPath;
 
-#pragma mark Calculation and Drawing Methods
+
+#pragma mark Rendering Methods
+/*!
+ @methodgroup Rendering Methods
+ */
+
+
+/*!
+    @method     createLineForString:
+    @abstract   Renders the specified string.
+ 
+    @discussion This method uses the normal font and the context inferred font
+                size to render the string. In most cases this is the appropriate 
+                method for rendering textual content in a layout.
+ 
+    @param      aString
+                The string to be rendered.
+ 
+    @return     A <code>CTLineRef</code> representing the rendered string.
+ */
 - (CTLineRef)createLineForString:(NSString *)aString;
+
+
+/*!
+    @method     createLineForString:emphasize:
+    @abstract   Renders the specified string.
+ 
+    @discussion This method uses either the normal or the special font depending
+                on the <code>emphasize</code> flag. It uses the context inferred
+                font size.
+ 
+    @param      aString
+                The string to be rendered.
+ 
+    @param      emphasize
+                A flag indicating whether the special font should be used.
+ 
+    @return     A <code>CTLineRef</code> representing the rendered string.
+ */
 - (CTLineRef)createLineForString:(NSString *)aString emphasize:(BOOL)emphasize;
+
+
+/*!
+    @method     createLineForString:usingFont:
+    @abstract   Renders the specified string in the specified font.
+ 
+    @discussion In most cases you do should prefer <code>@link
+                //apple_ref/occ/instm/MPLayout/createLineForString:@/link</code>
+                or <code>@link
+                //apple_ref/occ/instm/MPLayout/createLineForString:emphasize:@/link</code>
+                over this method.
+ 
+    @param      aString
+                The string to be rendered.
+ 
+    @param      font
+                The font to render <code>aString</code> in.
+ 
+    @return     A <code>CTLineRef</code> representing the rendered string.
+ */
 - (CTLineRef)createLineForString:(NSString *)aString usingFont:(NSFont *)font;
 
+
+/*!
+    @property   flipped
+    @abstract   This property indicates whether the receiver uses a flipped
+                layout.
+ 
+    @discussion The value of this property should be the same in the receiver,
+                its parent and all of its children.
+ */
 @property (nonatomic, getter = isFlipped) BOOL flipped;
+
+
+/*!
+    @property   usesSmallSize
+    @abstract   This property indicates whether the receiver uses the small font
+                size.
+ 
+    @discussion This property is used to determine the <code>@link
+                //apple_ref/occ/instm/MPLayout/contextInferredFontSize@/link</code>.
+                If this value is <code>YES</code> all of the receiver's children
+                should also use the small size. If not the children may or may
+                not (depending on the actual layout implementation) use the small
+                size.
+ */
 @property (nonatomic) BOOL usesSmallSize;
+
+
+/*!
+    @method     bounds
+    @abstract   Returns the receiver's bounds.
+ 
+    @discussion If the receiver has cached bounds it will return the cached
+                value. The cached value can be removed using the <code>@link
+                //apple_ref/occ/instm/MPLayout/invalidate@/link</code> method. If
+                there is no cached value this method will generate a new cached
+                value by calling the <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/generateBounds@/link</code>
+                method.
+
+    @return     The receiver's bounds.
+ */
 - (NSRect)bounds;
 
+
+/*!
+    @method     boundingRectForRangePath:
+    @abstract   Returns the rect relative to the origin of the receiver's bounds
+                that contains the symbols identified by the specified range path.
+ 
+    @discussion Use this method to determine where the user's selection should be
+                drawn at.
+ 
+    @param      rangePath
+                The range path whose bounds are needed.
+ 
+    @return     The rectangle containing the symbols identified by
+                <code>rangePath</code>.
+ */
 - (NSRect)boundingRectForRangePath:(MPRangePath *)rangePath; /* if rangePath.length is 0 the returned rect will have a width of 0 */
 
+
+/*!
+    @method     drawAtPoint:
+    @abstract   Draws the receiver at the specified point.
+ 
+    @discussion If the receiver returns <code>NO</code> from its <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/drawsChildrenManually@/link</code>
+                method this method also draws every single child of the receiver.
+                The location the children are drawn at is determined by the
+                <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/offsetOfChildLayoutAtIndex:@/link</code>
+                method.
+ 
+    @param      point
+                The point the receiver is to be drawn at.
+ */
 - (void)drawAtPoint:(NSPoint)point;
 
 @end
 
+
+
+/*!
+    @category   MPLayout (MPSubclassImplement)
+    @abstract   The methods in this category must be implemented by any concrete
+                subclass of <code>MPLayout</code>.
+ */
 @interface MPLayout (MPSubclassImplement)
+
+/*!
+    @method     numberOfChildren
+    @abstract   Returns the number of sublayouts of the receiver.
+ 
+    @discussion This method must be implemented by subclasses.
+ */
 - (NSUInteger)numberOfChildren;
+
+
+/*!
+    @method     drawsChildrenManually
+    @abstract   Returns whether the receiver wants to take over responsibility of
+                drawing its children.
+ 
+    @discussion If you return <code>YES</code> from this method
+                <code>MPLayout</code> does not draw the receiver's children. The
+                receiver's <code>//apple_ref/occ/intfm/MPLayout/draw</code>
+                method has to implement that functionality. If you return
+                <code>NO</code> from this method the receiver must not draw its
+                children in the <code>//apple_ref/occ/intfm/MPLayout/draw</code>
+                method.
+ 
+                This method may be implemented by subclasses to opt in and change
+                the default behaviour.
+
+    @return     <code>YES</code> if the receiver draws its children
+                automatically, <code>NO</code> otherwise. The default
+                implementation returns <code>NO</code>.
+ */
 - (BOOL)drawsChildrenManually;
-- (MPLayout *)childLayoutAtIndex:(NSUInteger)index; // To be implemented
-- (NSRect)generateBounds; // To be implemented
-- (NSRect)boundingRectForRange:(NSRange)range; // To be implemented, use rangePath instead, this one has wrong origin
+
+
+/*!
+    @method     childLayoutAtIndex:
+    @abstract   Returns the receiver's child at the specified index.
+ 
+    @discussion As long as the specified <code>index</code> does not exceed the
+                receiver's number of children, this method should always return a
+                value based on the following criteria:
+                1. If the receiver represents a <code>@link
+                   //apple_ref/occ/cl/MPFunction@/link</code> instance it should
+                   always return a valid <code>MPLayout</code> instance.
+                2. If the receiver represents a <code>@link
+                   //apple_ref/occ/cl/MPExpression@/link</code> instance it
+                   returns only a valid <code>MPLayout</code> instance if the
+                   represented expression's element at <code>index</code> is a
+                   function.
+
+                This method should cache any generated child layout and use the
+                cache whenever possible in order to reduce resources needed for
+                rendering.
+ 
+                This method must be implemented by subclasses.
+ 
+    @param      index
+                The index of the requested child layout.
+ 
+    @return     A <code>MPLayout</code> instance representing the respective
+                child of the object that is represented by the receiver, or
+                <code>nil</code> if the child represents a string element in an
+                expression.
+ */
+- (MPLayout *)childLayoutAtIndex:(NSUInteger)index;
+
+
+/*!
+    @method     generateBounds
+    @abstract   Calculates the receiever's bounds.
+ 
+    @discussion This method should not use any cached values. Caching of the
+                calculated bounds is done automatically by the
+                <code>MPLayout</code> class. This method is only called if the
+                receiving <code>MPLayout</code> instance has been invalidated and
+                the receiver's bounds have been requested.
+ 
+                This method must be implemented by subclasses.
+
+    @return     The receiver's bounds.
+ */
+- (NSRect)generateBounds;
+
+
+/*!
+    @method     boundingRectForRange:
+    @abstract   Returns the rectangle that encloses the symbols in the specified
+                range.
+
+    @discussion This method is called to calculate the rectangle that encloses
+                the user's selection. If the specified <code>range</code> has a
+                length of <code>0</code> the returned rectangle should be the
+                bounds of the caret (which has a width of <code>0</code>). The
+                height and y-origin of the returned rectangle should be equal to
+                the respective values of the receiver.
+ 
+                This method must be implemented by subclasses.
+ 
+    @param      range
+                The range of the selection whose bounds should be calculated.
+ 
+    @return     A rectangle enclosing the user's selection.
+ */
+- (NSRect)boundingRectForRange:(NSRange)range;
+
+
+/*!
+    @method     offsetOfChildLayoutAtIndex:
+    @abstract   Returns the location of the child layout at the specified index.
+ 
+    @discussion This method must be implemented by subclasses even if the
+                subclass returns <code>YES</code> from the <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/drawsChildrenManually@/link</code>
+                method.
+ 
+    @param      index
+                The index of the child whose location is to be calculated.
+ 
+    @return     The location of the child layout at the specified index relative
+                to the receiver.
+ */
 - (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index;
+
+
+/*!
+    @method     indexPathForMousePoint:
+    @abstract   Performs hit testing.
+ 
+    @discussion This method tests the specified <code>point</code> against all of
+                its children and returns the index path (relative to the index
+                path of the receiver) that identifies the location inside the
+                expression tree the user selected. The specified point must be
+                inside of the receiver and must be specified relatively to the
+                receiver. If the specified point is not inside any of the
+                receiver's children but in the receiver itself the returned index
+                path must contain one index specifiying the location in the
+                receiver.
+ 
+                This method must be implemented by subclasses.
+ 
+    @param      point
+                The point inside the receiver that is to be tested.
+ 
+    @return     The index path that points to the point the user selected. All
+                indexes in the path except for the last one are specified in the
+                element reference frame. The last index is specified in the
+                symbol reference frame.
+ */
 - (NSIndexPath *)indexPathForMousePoint:(NSPoint)point;
-- (void)draw; // To be implemented
+
+
+/*!
+    @method     draw
+    @abstract   Draws the receiver.
+ 
+    @discussion If the receiver returns <code>YES</code> from its <code>@link
+                //apple_ref/occ/instm/MPLayout(MPSubclassImplement)/drawsChildrenManually@/link</code>
+                method the implementation of this method must also draw the
+                receiver's children.
+ 
+                This method must be implemented by subclasses. If the receiver
+                does not have anything to draw except for its children you should
+                implement this method with an empty method body.
+ */
+- (void)draw;
+
 @end

MathKit/MPLayout.m

@@ -11,20 +11,25 @@
 #import "MPRangePath.h"
 #import "NSIndexPath+MPAdditions.h"
 
+
+
 @interface MPLayout ()
 
-// Querying and Storing Caches
 - (BOOL)hasCacheForElementAtIndex:(NSUInteger)index;
 - (void)ensureCacheSizeForIndex:(NSUInteger)index;
 
 @end
 
+
+
 @implementation MPLayout {
     NSMutableArray *_cache;
     NSRect _cachedBounds;
 }
 
 #pragma mark Creation Methods
+
+
 - (id)init
 {
     self = [super init];
@@ -35,6 +40,7 @@
     return self;
 }
 
+
 - (instancetype)initWithParent:(MPLayout *)parent
 {
     self = [self init];
@@ -44,41 +50,51 @@
     return self;
 }
 
+
 #pragma mark Properties
+
+
 - (NSFont *)normalFontWithSize:(CGFloat)size
 {
     return [NSFont fontWithName:@"CMU Serif"
                            size:size];
 }
 
+
 - (NSFont *)specialFontWithSize:(CGFloat)size
 {
     return [NSFont fontWithName:@"CMU Serif Italic"
                            size:size];
 }
 
+
 - (CGFloat)contextInferredFontSize
 {
     return self.usesSmallSize ? self.smallFontSize : self.normalFontSize;
 }
 
+
 - (CGFloat)normalFontSize
 {
     return 18.0;
 }
 
+
 - (CGFloat)smallFontSize
 {
     return 12.0;
 }
 
+
 - (NSFont *)font
 {
     return [self normalFontWithSize:self.contextInferredFontSize];
 }
 
+
 #pragma mark Cache Tree
-// Querying and Storing Caches
+
+
 - (BOOL)hasCacheForElementAtIndex:(NSUInteger)index
 {
     if (index >= _cache.count) {
@@ -87,6 +103,7 @@
     return _cache[index] != [NSNull null];
 }
 
+
 - (id)cachableObjectForIndex:(NSUInteger)index
                    generator:(id (^)())generator
 {
@@ -99,6 +116,7 @@
     return object;
 }
 
+
 - (void)ensureCacheSizeForIndex:(NSUInteger)index
 {
     while (index >= _cache.count) {
@@ -106,7 +124,7 @@
     }
 }
 
-// Clearing Caches
+
 - (void)clearCacheInRange:(NSRange)range
         replacementLength:(NSUInteger)replacementLength
 {
@@ -119,12 +137,14 @@
     [self invalidate];
 }
 
+
 - (void)invalidate
 {
     _cachedBounds = NSZeroRect;
     [self.parent invalidate];
 }
 
+
 - (MPLayout *)childLayoutAtIndexPath:(NSIndexPath *)indexPath
 {
     if (indexPath.length == 0) {
@@ -134,19 +154,24 @@
     return [child childLayoutAtIndexPath:[indexPath indexPathByRemovingFirstIndex]];
 }
 
+
 #pragma mark Calculation and Drawing Methods
+
+
 - (CTLineRef)createLineForString:(NSString *)aString
 {
     return [self createLineForString:aString
                            usingFont:self.font];
 }
 
+
 - (CTLineRef)createLineForString:(NSString *)aString emphasize:(BOOL)emphasize
 {
     return [self createLineForString:aString
                            usingFont:[NSFont systemFontOfSize:[NSFont systemFontSize]]];
 }
 
+
 - (CTLineRef)createLineForString:(NSString *)aString
                        usingFont:(NSFont *)font
 {
@@ -158,6 +183,7 @@
     return line;
 }
 
+
 - (NSRect)bounds
 {
     if (NSEqualRects(_cachedBounds, NSZeroRect)) {
@@ -166,6 +192,7 @@
     return _cachedBounds;
 }
 
+
 - (NSRect)boundingRectForRangePath:(MPRangePath *)rangePath
 {
     if (rangePath.location.length == 1) {
@@ -180,11 +207,13 @@
     return bounds;
 }
 
+
 - (BOOL)drawsChildrenManually
 {
     return NO;
 }
 
+
 - (void)drawAtPoint:(NSPoint)point
 {
     NSAffineTransform *transform = [NSAffineTransform transform];

MathKit/MPMathRules.h

@@ -7,25 +7,49 @@
 //
 
 
+/*!
+ @header
+ This file contains the <code>MPMathRules</code> class.
+ */
 
-FOUNDATION_EXPORT NSString *MPMathRulesMaximumOperatorChainLengthKey;
-FOUNDATION_EXPORT NSString *MPMathRulesMaximumOperatorChainLengthInMultiplicationKey;
+
+/*!
+    @const      MPMathRulesIsUsingDegreesKey
+    @abstract   Predefined key that is used to store the properties of the
+                <code>MPMathRules</code> class in the <code>NSUserDefaults</code>
+                database.
+ */
 FOUNDATION_EXPORT NSString *MPMathRulesIsUsingDegreesKey;
 
 
+
 @class MPMathRules;
 
 
+/*!
+    @class      MPMathRules
+    @abstract   The math rules class stores global settings concerning
+                mathematical interpretations
+    
+    @discussion The <code>MPMathRules</code> class is a singletone class. There
+                can only exist one instance (the shared instance) at any time.
+ */
 @interface MPMathRules : NSObject
 
+/*!
+    @method     sharedRules
+    @abstract   Returnes the shared <code>MPMathRules</code> instance.
+ */
 + (MPMathRules *)sharedRules;
 
-@property (nonatomic, getter = isUsingUserDefaultValues) BOOL usingUserDefaultValues;
 
-// Default value uses the key "..." in NSUserDefaults or ... if the key does not exist.
-@property (nonatomic) NSUInteger maximumOperatorChainLength; // +--++-5 -> Chain length: 6, 2 default (sign of number and operator) (0 is invalid?)
-@property (nonatomic) NSUInteger maximumOperatorChainLengthInMultiplication; // Default: 1, 0 means actually 0
+/*!
+    @property   isUsingDegrees
+    @abstract   Specifies whether trigonometric functions use degree values.
  
+    @discussion If set to <code>NO</code> radians are used instead. The default
+                value is <code>NO</code>.
+ */
 @property (nonatomic) BOOL isUsingDegrees;
 
 @end

MathKit/MPMathRules.m

@@ -8,14 +8,16 @@
 
 #import "MPMathRules.h"
 
-NSString *MPMathRulesMaximumOperatorChainLengthKey = @"MPMathRulesMaximumOperatorChainLengthKey";
-NSString *MPMathRulesMaximumOperatorChainLengthInMultiplicationKey = @"MPMathRulesMaximumOperatorChainLengthInMultiplicationKey";
+
 NSString *MPMathRulesIsUsingDegreesKey = @"MPMathRulesIsUsingDegreesKey";
 
+
+
 @implementation MPMathRules
 
 static MPMathRules *sharedRules;
 
+
 + (MPMathRules *)sharedRules
 {
     if (!sharedRules) {
@@ -24,6 +26,7 @@ static MPMathRules *sharedRules;
     return sharedRules;
 }
 
+
 - (instancetype)init
 {
     if (sharedRules) {
@@ -31,53 +34,21 @@ static MPMathRules *sharedRules;
     }
     self = [super init];
     if (self) {
-        _usingUserDefaultValues = YES;
-        NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
-        NSNumber *userDefaultsMaximumOperatorChainLength = [userDefaults objectForKey:MPMathRulesMaximumOperatorChainLengthKey];
-        NSNumber *userDefaultsMaximumOperatorChainLengthInMultiplication = [userDefaults objectForKey:MPMathRulesMaximumOperatorChainLengthInMultiplicationKey];
-        NSNumber *userDefaultsIsUsingDegrees = [userDefaults objectForKey:MPMathRulesIsUsingDegreesKey];
-        
-        _maximumOperatorChainLength = userDefaultsMaximumOperatorChainLength != nil ? userDefaultsMaximumOperatorChainLength.unsignedIntegerValue : 2;
-        _maximumOperatorChainLengthInMultiplication = userDefaultsMaximumOperatorChainLengthInMultiplication != nil ? userDefaultsMaximumOperatorChainLengthInMultiplication.unsignedIntegerValue : 1;
-        _isUsingDegrees = userDefaultsIsUsingDegrees.boolValue;
     }
     return self;
 }
 
-- (void)setUsingUserDefaultValues:(BOOL)usingUserDefaultValues
+
+- (BOOL)isUsingDegrees
 {
-    _usingUserDefaultValues = usingUserDefaultValues;
-    // Save the current values
-    self.maximumOperatorChainLength = self.maximumOperatorChainLength;
-    self.maximumOperatorChainLengthInMultiplication = self.maximumOperatorChainLengthInMultiplication;
-    self.isUsingDegrees = self.isUsingDegrees;
+    return [[NSUserDefaults standardUserDefaults] boolForKey:MPMathRulesIsUsingDegreesKey];
 }
 
-- (void)setMaximumOperatorChainLength:(NSUInteger)maximumOperatorChainLength
-{
-    _maximumOperatorChainLength = maximumOperatorChainLength;
-    if (self.isUsingUserDefaultValues) {
-        [[NSUserDefaults standardUserDefaults] setObject:@(maximumOperatorChainLength)
-                                                  forKey:MPMathRulesMaximumOperatorChainLengthKey];
-    }
-}
-
-- (void)setMaximumOperatorChainLengthInMultiplication:(NSUInteger)maximumOperatorChainLengthInMultiplication
-{
-    _maximumOperatorChainLengthInMultiplication = maximumOperatorChainLengthInMultiplication;
-    if (self.isUsingUserDefaultValues) {
-        [[NSUserDefaults standardUserDefaults] setObject:@(maximumOperatorChainLengthInMultiplication)
-                                                  forKey:MPMathRulesMaximumOperatorChainLengthInMultiplicationKey];
-    }
-}
 
 - (void)setIsUsingDegrees:(BOOL)isUsingDegrees
 {
-    _isUsingDegrees = isUsingDegrees;
-    if (self.isUsingUserDefaultValues) {
-        [[NSUserDefaults standardUserDefaults] setBool:isUsingDegrees
+    [[NSUserDefaults standardUserDefaults] setBool:isUsingDegrees
                                                 forKey:MPMathRulesIsUsingDegreesKey];
-    }
 }
 
 @end

MathKit/MPNegatedTerm.h

@@ -9,6 +9,12 @@
 #import "MPTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPNegatedTerm</code> class.
+ */
+
+
 
 @class MPNegatedTerm;
 
@@ -20,7 +26,6 @@
  */
 @interface MPNegatedTerm : MPTerm
 
-
 /*!
     @method     initWithTerm:
     @abstract   Initializes a new negated term.
@@ -34,8 +39,8 @@
 
 
 /*!
- @property   term
- @abstract   The receiver's term.
+    @property   term
+    @abstract   The receiver's term.
  */
 @property (readonly, nonatomic, strong) MPTerm *term;
 

MathKit/MPNegatedTerm.m

@@ -8,6 +8,8 @@
 
 #import "MPNegatedTerm.h"
 
+
+
 @implementation MPNegatedTerm
 
 - (instancetype)initWithTerm:(MPTerm *)term
@@ -20,6 +22,7 @@
     return self;
 }
 
+
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
     NSDecimalNumber *value = [self.term evaluate:error];

MathKit/MPNumber.h

@@ -9,14 +9,44 @@
 #import "MPTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPNumber</code> class.
+ */
+
+
 
 @class MPNumber;
 
 
+/*!
+    @class      MPNumber
+    @abstract   This class represents a number that evaluates to itself.
+ 
+    @discussion Numbers include integers as well as floating point numbers. They
+                have to be representable as a decimal number literal (e.g.
+                <code>3.4</code>). Numbers that have periods or are irrational
+                are not implemented by this class.
+ */
 @interface MPNumber : MPTerm
 
+/*!
+    @method     initWithNumber:
+    @abstract   Initializes a number term with the specified <code>number</code>.
+ 
+    @param      number
+                The number that the term should evaluate to. Must not be
+                <code>nil</code>.
+ 
+    @return     A new <code>MPNumberTerm</code> instance.
+ */
 - (instancetype)initWithNumber:(NSDecimalNumber *)number; /* designated initializer */
 
+
+/*!
+    @property   number
+    @abstract   The receiver's number.
+ */
 @property (readonly, nonatomic, strong) NSDecimalNumber *number;
 
 @end

MathKit/MPNumber.m

@@ -8,9 +8,7 @@
 
 #import "MPNumber.h"
 
-#import "MPParsedExpression.h"
 
-#import "MPToken.h"
 
 @implementation MPNumber
 
@@ -24,6 +22,7 @@
     return self;
 }
 
+
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
     return self.number;

MathKit/MPParenthesisFunction.h

@@ -9,6 +9,12 @@
 #import "MPFunction.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPParenthesisFunction</code> class.
+ */
+
+
 
 @class MPParenthesisFunction, MPExpression;
 

MathKit/MPParenthesisFunction.m

@@ -18,16 +18,19 @@
 
 MPFunctionAccessorImplementation(Expression, _expression)
 
+
 - (NSArray *)childrenAccessors
 {
     return @[@"expression"];
 }
 
+
 - (Class)functionTermClass
 {
     return [MPParenthesisTerm class];
 }
 
+
 - (NSString *)description
 {
     return [NSString stringWithFormat:@"(%@)", self.expression.description];

MathKit/MPParenthesisFunctionLayout.h

@@ -9,12 +9,32 @@
 #import "MPFunctionLayout.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPParenthesisFunctionLayout</code> class.
+ */
+
+
 
 @class MPParenthesisFunctionLayout, MPParenthesisFunction;
 
 
+/*!
+    @class      MPParenthesisFunctionLayout
+    @abstract   A parenthesis function layout displays a <code>@link
+                //apple_ref/occ/cl/MPParenthesisFunction@/link</code>.
+ 
+    @discussion The child of the parenthesis function is encapsulated by standard
+                parenthesis that are scaled to the smae height as the child.
+ */
 @interface MPParenthesisFunctionLayout : MPFunctionLayout
 
+/*!
+    @method     parenthesisFunction
+    @abstract   Returns the <code>@link
+                //apple_ref/occ/cl/MPParenthesisFunction@/link</code> represented
+                by the receiver.
+ */
 - (MPParenthesisFunction *)parenthesisFunction;
 
 @end

MathKit/MPParenthesisFunctionLayout.m

@@ -10,9 +10,12 @@
 
 #import "MPParenthesisFunction.h"
 
+
 #define MPParenthesisFunctionOpeningParensOffset 2
 #define MPParenthesisFunctionClosingParensOffset 0
 
+
+
 @interface MPParenthesisFunctionLayout ()
 
 - (NSBezierPath *)openingParens;
@@ -25,6 +28,8 @@
 
 @end
 
+
+
 @implementation MPParenthesisFunctionLayout
 
 - (MPParenthesisFunction *)parenthesisFunction
@@ -32,6 +37,7 @@
     return (MPParenthesisFunction *)self.function;
 }
 
+
 - (NSBezierPath *)openingParens
 {
     NSBezierPath *parens = [self objectForPrivateCacheIndex:0 generator:^id{
@@ -60,6 +66,7 @@
     return parens;
 }
 
+
 - (NSBezierPath *)closingParens
 {
     NSBezierPath *parens = [self objectForPrivateCacheIndex:1 generator:^id{
@@ -88,6 +95,7 @@
     return parens;
 }
 
+
 - (NSBezierPath *)transformedOpeningParens
 {
     NSBezierPath *parens = self.openingParens.copy;
@@ -95,6 +103,7 @@
     return parens;
 }
 
+
 - (NSBezierPath *)transformedClosingParens
 {
     NSBezierPath *parens = self.closingParens.copy;
@@ -102,6 +111,7 @@
     return parens;
 }
 
+
 - (NSAffineTransform *)parenthesisTransform
 {
     NSAffineTransform *transform = [NSAffineTransform transform];
@@ -110,6 +120,7 @@
     return transform;
 }
 
+
 - (CGFloat)scaleFactor
 {
     NSRect parensBounds = self.openingParens.bounds;
@@ -122,22 +133,25 @@
     return expressionHeight / parensHeight;
 }
 
+
 - (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
 {
     return NSMakePoint(self.openingParens.bounds.size.width + MPParenthesisFunctionOpeningParensOffset, 0);
 }
 
+
 - (NSIndexPath *)indexPathForLocalMousePoint:(NSPoint)point
 {
-#warning Missing Implementation
     return [NSIndexPath indexPathWithIndex:0];
 }
 
+
 - (NSIndexSet *)indexesOfRemainingChildren
 {
     return [NSIndexSet indexSetWithIndex:0];
 }
 
+
 - (NSRect)generateBounds
 {
     NSRect openingParensBounds = self.transformedOpeningParens.bounds;
@@ -159,6 +173,7 @@
     return bounds;
 }
 
+
 - (void)draw
 {
     NSBezierPath *openingParens = self.transformedOpeningParens;

MathKit/MPParenthesisTerm.h

@@ -9,10 +9,24 @@
 #import "MPFunctionTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPParenthesisTerm</code> class.
+ */
+
+
 
 @class MPParenthesisTerm;
 
 
+/*!
+    @class      MPParenthesisTerm
+    @abstract   Represents a <code>@link
+                //apple_ref/occ/cl/MPParenthesisFunction@/link</code>.
+ 
+    @discussion A parenthesis function encapsulates a term and thus prioritizes
+                it in evaluation.
+ */
 @interface MPParenthesisTerm : MPFunctionTerm
 
 @end

MathKit/MPParenthesisTerm.m

@@ -10,6 +10,8 @@
 
 #import "MPParsedExpression.h"
 
+
+
 @implementation MPParenthesisTerm
 
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error

MathKit/MPParsedExpression.h

@@ -7,8 +7,10 @@
 //
 
 
-
-@class MPParsedExpression, MPTerm;
+/*!
+ @header
+ This file contains the <code>MPParsedExpression</code> class.
+ */
 
 
 /*!
@@ -50,6 +52,10 @@ FOUNDATION_EXPORT NSString *const MPPathToExpressionKey;
 FOUNDATION_EXPORT NSString *const MPErrorRangeKey;
 
 
+
+@class MPParsedExpression, MPTerm;
+
+
 /*!
     @class      MPParsedExpression
     @abstract   A parsed expression represents an expression whose syntax is
@@ -93,7 +99,7 @@ FOUNDATION_EXPORT NSString *const MPErrorRangeKey;
 
     @discussion This method is a convenience method for evaluating the receiver's
                 <code>@link
-                //apple_ref/occ/intfp/MPParsedExpression/term@/link</code>.
+                //apple_ref/occ/instp/MPParsedExpression/term@/link</code>.
  
     @param      error
                 If an error occured during evaluation it will be returned

MathKit/MPParsedExpression.m

@@ -9,13 +9,15 @@
 #import "MPParsedExpression.h"
 
 #import "MPToken.h"
-
 #import "MPTerm.h"
 
+
 NSString *const MPMathKitErrorDomain = @"MPMathKitErrorDomain";
 NSString *const MPPathToExpressionKey = @"MPPathToExpressionKey";
 NSString *const MPErrorRangeKey = @"MPErrorRangeKey";
 
+
+
 @implementation MPParsedExpression
 
 - (NSDecimalNumber *)evaluate:(NSError *__autoreleasing *)error

MathKit/MPPowerFunction.h

@@ -9,6 +9,12 @@
 #import "MPFunction.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPPowerFunction</code> class.
+ */
+
+
 
 @class MPPowerFunction, MPExpression;
 

MathKit/MPPowerFunction.m

@@ -10,15 +10,19 @@
 
 #import "MPExpression.h"
 
+
+
 @implementation MPPowerFunction
 
 MPFunctionAccessorImplementation(ExponentExpression, _exponentExpression)
 
+
 - (NSArray *)childrenAccessors
 {
     return @[@"exponentExpression"];
 }
 
+
 - (NSString *)description
 {
     return [NSString stringWithFormat:@"^%@", self.exponentExpression.description];

MathKit/MPPowerFunctionLayout.h

@@ -9,14 +9,46 @@
 #import "MPFunctionLayout.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPPowerFunctionLayout</code> class.
+ */
+
+
 
 @class MPPowerFunctionLayout, MPPowerFunction;
 
 
+/*!
+    @class      MPPowerFunctionLayout
+    @abstract   A power function layout displays a <code>@link
+                //apple_ref/occ/cl/MPPowerFunction@/link</code>.
+ 
+    @discussion A power function layout draws its child at the top right of the
+                base. Because of this the power function layout has a special
+                property that gets set during the drawing of an expression:
+                <code>@link
+                //apple_ref/occ/instp/MPPowerFunctionLayout/baseBounds@/link</code>.
+ */
 @interface MPPowerFunctionLayout : MPFunctionLayout
 
+/*!
+    @property   baseBounds
+    @abstract   The bounds of the expression that is the base of the receiving
+                power function layout.
+ 
+    @discussion This value should be considered very volatile. It may change even
+                if the power function itself didn't. This value is guaranteed to
+                stay the same only during a single cycle of drawing.
+ */
 @property (nonatomic) NSRect baseBounds;
 
+/*!
+    @method     powerFunction
+    @abstract   Returns the <code>@link
+                //apple_ref/occ/cl/MPPowerFunction@/link</code> represented by
+                the receiver.
+ */
 - (MPPowerFunction *)powerFunction;
 
 @end

MathKit/MPPowerFunctionLayout.m

@@ -10,9 +10,12 @@
 
 #import "MPPowerFunction.h"
 
+
 #define kPowerFunctionExponentXOffset 1
 #define kPowerFunctionTrailingOffset 2
 
+
+
 @implementation MPPowerFunctionLayout
 
 - (NSRect)baseBounds
@@ -23,16 +26,19 @@
     return _baseBounds;
 }
 
+
 - (MPPowerFunction *)powerFunction
 {
     return (MPPowerFunction *)self.function;
 }
 
+
 - (NSIndexSet *)indexesOfRemainingChildren
 {
     return [NSIndexSet indexSetWithIndex:0];
 }
 
+
 #warning Broken Power Layout
 - (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
 {
@@ -41,16 +47,19 @@
     return NSMakePoint(kPowerFunctionExponentXOffset, y);
 }
 
+
 - (BOOL)childAtIndexUsesSmallSize:(NSUInteger)index
 {
     return YES;
 }
 
+
 - (NSIndexPath *)indexPathForLocalMousePoint:(NSPoint)point
 {
     return [[NSIndexPath indexPathWithIndex:0] indexPathByAddingIndex:0];
 }
 
+
 - (NSRect)generateBounds
 {
     NSRect exponentBounds = [self childLayoutAtIndex:0].bounds;
@@ -59,9 +68,8 @@
     return NSMakeRect(0, 0, width, height);
 }
 
+
 - (void)draw
-{
-    [[NSBezierPath bezierPathWithRect:self.bounds] stroke];
-}
+{}
 
 @end

MathKit/MPPowerTerm.h

@@ -9,12 +9,33 @@
 #import "MPFunctionTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPPowerTerm</code> class.
+ */
+
+
 
 @class MPPowerTerm, MPTerm;
 
 
+/*!
+    @class      MPPowerTerm
+    @abstract   Represents a <code>@link
+                //apple_ref/occ/cl/MPPowerFunction@/link</code>.
+ 
+    @discussion A power function is evaluated using the C <code>pow</code>
+                function.
+ */
 @interface MPPowerTerm : MPFunctionTerm
 
+/*!
+    @property   baseTerm
+    @abstract   The base of the power.
+ 
+    @discussion This value is set during the evaluation of the power term and 
+                should be considered very volatile.
+ */
 @property (nonatomic, strong) MPTerm *baseTerm;
 
 @end

MathKit/MPPowerTerm.m

@@ -7,8 +7,11 @@
 //
 
 #import "MPPowerTerm.h"
+
 #import "MPParsedExpression.h"
 
+
+
 @implementation MPPowerTerm
 
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error

MathKit/MPProductTerm.h

@@ -9,6 +9,12 @@
 #import "MPTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPProductTerm</code> class.
+ */
+
+
 
 @class MPProductTerm;
 
@@ -22,7 +28,6 @@
  */
 @interface MPProductTerm : MPTerm
 
-
 /*!
     @method     initWithFactors:
     @abstract   Initializes a new product term with the specified

MathKit/MPProductTerm.m

@@ -8,17 +8,7 @@
 
 #import "MPProductTerm.h"
 
-#import "MPParsedExpression.h"
-#import "MPPowerFunction.h"
 
-#import "MPFunctionTerm.h"
-#import "MPElementaryFunctionTerm.h"
-#import "MPNumber.h"
-#import "MPFactorialTerm.h"
-#import "MPPowerTerm.h"
-#import "MPVariable.h"
-
-#import "MPToken.h"
 
 @implementation MPProductTerm
 
@@ -33,6 +23,7 @@
     return self;
 }
 
+
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
     NSDecimalNumber *value = [NSDecimalNumber one];

MathKit/MPRangePath.h

@@ -11,6 +11,8 @@
 
 /*!
  @header
+ This file contains the <code>MPRangePath</code> class.
+ 
  The <code>MPRangePath</code> combines an <code>NSIndexPath</code> with a
  <code>NSRange</code>. A range path is used in a tree structure to identify a
  number of subsequent nodes. This is achieved by combining a range path that
@@ -36,6 +38,7 @@
 #define MPMakeRangePath(loc, len) [MPRangePath rangePathWithLocation:(loc) length:(len)]
 
 
+
 @class MPRangePath, MPExpression;
 
 
@@ -268,7 +271,6 @@
 
 @interface MPExpression (MPRangeExtension)
 
-
 /*!
     @method     subexpressionWithRangePath:
     @abstract   Creates a new expression with the symbols in the specified range

MathKit/MPRangePath.m

@@ -12,7 +12,6 @@
 
 @implementation MPRangePath
 
-
 #pragma mark Creation Methods
 
 

MathKit/MPSumFunction.h

@@ -9,6 +9,12 @@
 #import "MPFunction.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPSumFunction</code> class.
+ */
+
+
 
 @class MPSumFunction, MPExpression;
 

MathKit/MPSumFunction.m

@@ -15,7 +15,6 @@
 
 @implementation MPSumFunction
 
-
 MPFunctionAccessorImplementation(StartExpression, _startExpression)
 MPFunctionAccessorImplementation(TargetExpression, _targetExpression)
 MPFunctionAccessorImplementation(SumExpression, _sumExpression)
@@ -26,11 +25,13 @@ MPFunctionAccessorImplementation(SumExpression, _sumExpression)
     return @[@"startExpression", @"targetExpression", @"sumExpression"];
 }
 
+
 - (BOOL)expectsVariableDefinitionInChildAtIndex:(NSUInteger)index
 {
     return index == 0;
 }
 
+
 - (Class)functionTermClass
 {
     return [MPSumFunctionTerm class];

MathKit/MPSumFunctionLayout.h

@@ -9,12 +9,33 @@
 #import "MPFunctionLayout.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPSumFunctionLayout</code> class.
+ */
+
+
 
 @class MPSumFunctionLayout, MPSumFunction;
 
 
+/*!
+    @class      MPSumFunctionLayout
+    @abstract   A sum function layout displays a <code>@link
+                //apple_ref/occ/cl/MPSumFunction@/link</code>.
+ 
+    @discussion A sum is drawn using a capital greeg sigma (∑) The three children
+                are placed around it: The start expression below, target
+                expression above and sum expression to the right of it.
+ */
 @interface MPSumFunctionLayout : MPFunctionLayout
 
+/*!
+    @method     sumFunction
+    @abstract   Returns the <code>@link
+                //apple_ref/occ/cl/MPSumFunction@/link</code> represented by the
+                receiver.
+ */
 - (MPSumFunction *)sumFunction;
 
 @end

MathKit/MPSumFunctionLayout.m

@@ -9,14 +9,16 @@
 #import "MPSumFunctionLayout.h"
 
 #import "MPSumFunction.h"
-
 #import "NSIndexPath+MPAdditions.h"
 
+
 #define kSumFunctionStartExpressionOffset 0
 #define kSumFunctionTargetExpressionOffset 0
 #define kSumFunctionSumExpressionOffset 3
 #define kSumFunctionTrailingOffset 5
 
+
+
 @implementation MPSumFunctionLayout
 
 - (MPSumFunction *)sumFunction
@@ -24,16 +26,19 @@
     return (MPSumFunction *)self.function;
 }
 
+
 - (NSUInteger)indexOfLeadingChild
 {
     return 2;
 }
 
+
 - (NSUInteger)indexOfTrailingChild
 {
     return 2;
 }
 
+
 - (NSUInteger)indexOfChildAfterChildAtIndex:(NSUInteger)index
 {
     if (index != 2) {
@@ -42,21 +47,25 @@
     return [super indexOfChildAfterChildAtIndex:index];
 }
 
+
 - (NSUInteger)indexOfChildBelowChildAtIndex:(NSUInteger)index
 {
     return 0;
 }
 
+
 - (NSUInteger)indexOfChildAboveChildAtIndex:(NSUInteger)index
 {
     return 1;
 }
 
+
 - (NSIndexSet *)indexesOfRemainingChildren
 {
     return [NSIndexSet indexSetWithIndex:2];
 }
 
+
 - (CTLineRef)line
 {
     CTLineRef line = [self lineForPrivateCacheIndex:0 generator:^CTLineRef{
@@ -67,6 +76,7 @@
     return line;
 }
 
+
 - (NSRect)localLineBounds
 {
     NSRect lineBounds = CTLineGetBoundsWithOptions(self.line, 0);
@@ -77,6 +87,7 @@
     return NSMakeRect(xPosition, lineBounds.origin.y, lineBounds.size.width, lineBounds.size.height);
 }
 
+
 - (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
 {
     NSRect childBounds = [self childLayoutAtIndex:index].bounds;
@@ -101,11 +112,13 @@
     return offset;
 }
 
+
 - (BOOL)childAtIndexUsesSmallSize:(NSUInteger)index
 {
     return (index == 0 || index == 1) ? YES : self.usesSmallSize;
 }
 
+
 - (NSIndexPath *)indexPathForLocalMousePoint:(NSPoint)point
 {
     if (point.x < CTLineGetBoundsWithOptions(self.line, 0).size.width / 2) {
@@ -115,6 +128,7 @@
     }
 }
 
+
 - (NSRect)generateBounds
 {
     NSRect lineBounds = CTLineGetBoundsWithOptions(self.line, 0);
@@ -139,6 +153,7 @@
     return bounds;
 }
 
+
 - (void)draw
 {
     // Get the current context

MathKit/MPSumFunctionTerm.h

@@ -8,11 +8,30 @@
 
 #import "MPFunctionTerm.h"
 
+/*!
+ @header
+ This file contains the <code>MPSumFunctionTerm</code> class.
+ */
+
 
 
 @class MPSumFunctionTerm;
 
 
+/*!
+    @class      MPSumFunctionTerm
+    @abstract   Represents and evaluates a <code>@link
+                //apple_ref/occ/cl/MPSumFunction@/link</code>.
+ 
+    @discussion A sum function evaluates its sum term <code>n</code> times. How
+                often it actually is evaluated depends on the boundary
+                expressions (start and target). Both are inclusive.
+ 
+                A sum function also features a variable that contains the current
+                value of the iteration. The variable is defined in the start
+                expression and incremented by <code>1</code> after every
+                iteration.
+ */
 @interface MPSumFunctionTerm : MPFunctionTerm
 
 @end

MathKit/MPSumFunctionTerm.m

@@ -10,6 +10,8 @@
 
 #import "MPParsedExpression.h"
 
+
+
 @implementation MPSumFunctionTerm
 
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error

MathKit/MPSumTerm.h

@@ -9,6 +9,12 @@
 #import "MPTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPSumTerm</code> class.
+ */
+
+
 
 @class MPSumTerm;
 

MathKit/MPSumTerm.m

@@ -8,10 +8,7 @@
 
 #import "MPSumTerm.h"
 
-#import "MPParsedExpression.h"
-#import "MPProductTerm.h"
 
-#import "MPToken.h"
 
 @implementation MPSumTerm
 
@@ -26,6 +23,7 @@
     return self;
 }
 
+
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
     NSDecimalNumber *value = [NSDecimalNumber zero];

MathKit/MPTerm.h

@@ -9,6 +9,8 @@
 
 /*!
  @header
+ This file contains the <code>MPTerm</code> class.
+ 
  The <code>MPTerm</code> class is used to evaluate a mathematical expression. A
  term is a purely mathematical representation of a part of an expression. A term
  can be defined with three rules:
@@ -66,6 +68,7 @@
 #define ReturnNilIfNil(test) if (test == nil) return nil
 
 
+
 @class MPTerm;
 
 

MathKit/MPTerm.m

@@ -9,9 +9,10 @@
 #import "MPTerm.h"
 
 #import "MPParsedExpression.h"
-#import "MPSumTerm.h"
 #import "MPEvaluationContext.h"
 
+
+
 @implementation MPTerm
 
 - (NSDecimalNumber *)evaluate:(NSError *__autoreleasing *)error
@@ -22,6 +23,7 @@
     return result;
 }
 
+
 - (BOOL)defineVariable:(NSString *)variableName
                  value:(NSDecimalNumber *)value
                  error:(NSError *__autoreleasing *)error
@@ -39,6 +41,7 @@
     return couldDefineVariable;
 }
 
+
 - (NSDecimalNumber *)valueForVariable:(NSString *)variableName
                                 error:(NSError *__autoreleasing *)error
 {
@@ -54,6 +57,7 @@
     return value;
 }
 
+
 - (void)undefineVariable:(NSString *)variableName
 {
     [[MPEvaluationContext sharedContext] undefineVariable:variableName];

MathKit/MPToken.h

@@ -9,6 +9,8 @@
 
 /*!
  @header
+ This file contains the <code>MPToken</code> class and protocol.
+ 
  One way to represent a mathematical expression using the <code>@link
  MPExpression@/link</code> class is a sequence of tokens. A token is a logical
  unit of input. The different types of units are identified by a @link
@@ -30,10 +32,6 @@ while ((token = [self nextToken]).tokenType != MPEOFToken) {
  */
 
 
-@class MPToken;
-@protocol MPToken;
-
-
 /*!
     @typedef    MPTokenType
     @abstract   The type of a token identifies its behaviour in a mathematical
@@ -103,6 +101,10 @@ typedef enum {
 
 
 
+@class MPToken;
+@protocol MPToken;
+
+
 /*!
     @protocol   MPToken
     @abstract   Tokens represent logical units in an expresion.

MathKit/MPVariable.h

@@ -9,14 +9,44 @@
 #import "MPTerm.h"
 
 
+/*!
+ @header
+ This file contains the <code>MPVariable</code> class.
+ */
+
+
 
 @class MPVariable;
 
 
+/*!
+    @class      MPVariable
+    @abstract   This class represents a variable.
+ 
+    @discussion Variables are evaluated in the <code>@link
+                //apple_ref/occ/cl/MPEvaluationContext@/link</code> and generate
+                errors if they are not defined.
+ */
 @interface MPVariable : MPTerm
 
+/*!
+    @method     initWithVariableName:
+    @abstract   Initializes a <code>MPVariable</code> with the specified
+                <code>variableName</code>
+
+    @param      variableName
+                The name of the variable. Must not be <code>nil</code> and must
+                be at least one character long.
+ 
+    @return     A new <code>MPVariable</code> instance.
+ */
 - (instancetype)initWithVariableName:(NSString *)variableName; /* designated initializer */
 
+
+/*!
+    @property   variableName
+    @abstract   The receiver's variable name.
+ */
 @property (readonly, nonatomic, strong) NSString *variableName;
 
 @end

MathKit/MPVariable.m

@@ -8,12 +8,7 @@
 
 #import "MPVariable.h"
 
-#import "MPParsedExpression.h"
 
-#import "MPToken.h"
-
-#import "MPExpression.h"
-#import "MPEvaluationContext.h"
 
 @implementation MPVariable
 
@@ -22,11 +17,13 @@
     self = [super init];
     if (self) {
         NSAssert(variableName != nil, @"variableName must not be nil.");
+        NSAssert(variableName.length > 0, @"variableName must be at least one character long.");
         _variableName = variableName;
     }
     return self;
 }
 
+
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
     return [self valueForVariable:self.variableName

MathKit/MPWhiteView.h

@@ -7,10 +7,20 @@
 //
 
 
+/*!
+ @header
+ This file contains the <code>MPWhiteView</code> class.
+ */
+
+
 
 @class MPWhiteView;
 
 
+/*!
+ @class      MPWhiteView
+ @abstract   A <code>NSView</code> that draws a white square in its frame.
+ */
 @interface MPWhiteView : NSView
 
 @end

MathKit/MathKit.h

@@ -6,20 +6,19 @@
 //  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
 //
 
-#import "MPExpression.h"
 #import "MPExpression.h"
 #import "NSString+MPExpressionElement.h"
 #import "MPFunction.h"
-
-#import "MPSumFunction.h"
-#import "MPParenthesisFunction.h"
-#import "MPPowerFunction.h"
-#import "MPFractionFunction.h"
-
 #import "MPToken.h"
 #import "MPFunction+MPToken.h"
 
+#import "MPFractionFunction.h"
+#import "MPParenthesisFunction.h"
+#import "MPPowerFunction.h"
+#import "MPSumFunction.h"
 
+#import "MPParsedExpression.h"
+#import "MPTerm.h"
 #import "MPEvaluationContext.h"
 #import "MPMathRules.h"
 
@@ -27,5 +26,13 @@
 #import "NSIndexPath+MPAdditions.h"
 #import "NSRegularExpression+MPParsingAdditions.h"
 
-#import "MPExpressionView.h"
 #import "MPExpressionStorage.h"
+#import "MPExpressionView.h"
+#import "MPLayout.h"
+#import "MPExpressionLayout.h"
+#import "MPFunctionLayout.h"
+
+#import "MPFractionFunctionLayout.h"
+#import "MPParenthesisFunctionLayout.h"
+#import "MPPowerFunctionLayout.h"
+#import "MPSumFunctionLayout.h"

MathKit/NSIndexPath+MPAdditions.h

@@ -7,6 +7,12 @@
 //
 
 
+/*!
+ @header
+ This file contains the <code>NSIndexPath(MPAdditions)</code> category.
+ */
+
+
 
 /*!
     @category   NSIndexPath (MPAdditions)
@@ -15,7 +21,6 @@
  */
 @interface NSIndexPath (MPAdditions)
 
-
 /*!
     @property   firstIndex
     @abstract   The first index from the receiver.

MathKit/NSIndexPath+MPAdditions.m

@@ -12,7 +12,6 @@
 
 @implementation NSIndexPath (MPAdditions)
 
-
 - (NSUInteger)firstIndex
 {
     return [self indexAtPosition:0];

MathKit/NSRegularExpression+MPParsingAdditions.h

@@ -7,6 +7,13 @@
 //
 
 
+/*!
+ @header
+ This file contains the <code>NSRegularExpression(MPParsingAdditions)</code>
+ category.
+ */
+
+
 
 /*!
     @category   NSRegularExpression (MPParsingAdditions)
@@ -15,7 +22,6 @@
  */
 @interface NSRegularExpression (MPParsingAdditions)
 
-
 /*!
     @method     firstMathInString:
     @abstract   Returns the first match of the regular expression within the

MathKit/NSString+MPExpressionElement.h

@@ -9,11 +9,18 @@
 #import "MPExpression.h"
 
 
+/*!
+ @header
+ This file contains the <code>NSString(MPExpressionElement)</code> category.
+ */
+
+
 
 /*!
     @category   NSString (MPExpressionElement)
-    @abstract   This category adds <code>@link MPExpressionElement@/link</code>
-                protocol conformance to the <code>NSString</code> class.
+    @abstract   This category adds <code>@link
+                //apple_ref/occ/intf/MPExpressionElement@/link</code> protocol
+                conformance to the <code>NSString</code> class.
  */
 @interface NSString (MPExpressionElement) <MPExpressionElement>
 

MathPad.xcodeproj/project.pbxproj

@@ -253,8 +253,6 @@
 		3B85832719BB5E5500D76A8D /* en */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = en; path = en.lproj/InfoPlist.strings; sourceTree = "<group>"; };
 		3B85833219BB5F2D00D76A8D /* MathKit.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MathKit.h; sourceTree = "<group>"; };
 		3BBBA3941905704200824E74 /* MPRangeTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = MPRangeTests.m; path = ../MathPadTests/MPRangeTests.m; sourceTree = "<group>"; };
-		3BC4661519B365070033F13A /* MPArrayCache.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MPArrayCache.h; sourceTree = "<group>"; };
-		3BC4661619B365070033F13A /* MPArrayCache.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MPArrayCache.m; sourceTree = "<group>"; };
 		3BF9976B18DE623E009CF6C4 /* MathPad.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = MathPad.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		3BF9976E18DE623E009CF6C4 /* Cocoa.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Cocoa.framework; path = System/Library/Frameworks/Cocoa.framework; sourceTree = SDKROOT; };
 		3BF9977118DE623E009CF6C4 /* AppKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = AppKit.framework; path = System/Library/Frameworks/AppKit.framework; sourceTree = SDKROOT; };
@@ -460,15 +458,6 @@
 			name = "Function Layouts";
 			sourceTree = "<group>";
 		};
-		3BC4661819B3692A0033F13A /* Temp */ = {
-			isa = PBXGroup;
-			children = (
-				3BC4661519B365070033F13A /* MPArrayCache.h */,
-				3BC4661619B365070033F13A /* MPArrayCache.m */,
-			);
-			name = Temp;
-			sourceTree = "<group>";
-		};
 		3BC46B4B19B38CB60033F13A /* Base Expression Classes */ = {
 			isa = PBXGroup;
 			children = (
@@ -510,22 +499,22 @@
 				3B6338671A3A4C2B00698BFB /* MPParsedExpression.m */,
 				3B63387A1A3A4C7E00698BFB /* MPTerm.h */,
 				3B63387B1A3A4C7E00698BFB /* MPTerm.m */,
-				3B6338601A3A4C2B00698BFB /* MPNegatedTerm.h */,
-				3B6338611A3A4C2B00698BFB /* MPNegatedTerm.m */,
 				3B6338781A3A4C7E00698BFB /* MPSumTerm.h */,
 				3B6338791A3A4C7E00698BFB /* MPSumTerm.m */,
 				3B63386A1A3A4C2B00698BFB /* MPProductTerm.h */,
 				3B63386B1A3A4C2B00698BFB /* MPProductTerm.m */,
-				3B6338841A3A4CA500698BFB /* MPFactorialTerm.h */,
-				3B6338851A3A4CA500698BFB /* MPFactorialTerm.m */,
+				3B6338601A3A4C2B00698BFB /* MPNegatedTerm.h */,
+				3B6338611A3A4C2B00698BFB /* MPNegatedTerm.m */,
+				3B63388C1A3A4CBE00698BFB /* MPFunctionTerm.h */,
+				3B63388D1A3A4CBE00698BFB /* MPFunctionTerm.m */,
 				3B6338881A3A4CAF00698BFB /* MPElementaryFunctionTerm.h */,
 				3B6338891A3A4CAF00698BFB /* MPElementaryFunctionTerm.m */,
 				3B6338621A3A4C2B00698BFB /* MPNumber.h */,
 				3B6338631A3A4C2B00698BFB /* MPNumber.m */,
 				3B63387C1A3A4C7E00698BFB /* MPVariable.h */,
 				3B63387D1A3A4C7E00698BFB /* MPVariable.m */,
-				3B63388C1A3A4CBE00698BFB /* MPFunctionTerm.h */,
-				3B63388D1A3A4CBE00698BFB /* MPFunctionTerm.m */,
+				3B6338841A3A4CA500698BFB /* MPFactorialTerm.h */,
+				3B6338851A3A4CA500698BFB /* MPFactorialTerm.m */,
 				3B6338901A3A4CCA00698BFB /* MPEvaluationContext.h */,
 				3B6338911A3A4CCA00698BFB /* MPEvaluationContext.m */,
 				3B6338941A3A4CD100698BFB /* MPMathRules.h */,
@@ -538,14 +527,14 @@
 		3BEFF75F1A17FF5C00301C0C /* Functions */ = {
 			isa = PBXGroup;
 			children = (
-				3B6338981A3A4CE100698BFB /* MPSumFunctionTerm.h */,
-				3B6338991A3A4CE100698BFB /* MPSumFunctionTerm.m */,
+				3B63389C1A3A4CEF00698BFB /* MPFractionTerm.h */,
+				3B63389D1A3A4CEF00698BFB /* MPFractionTerm.m */,
 				3B6338641A3A4C2B00698BFB /* MPParenthesisTerm.h */,
 				3B6338651A3A4C2B00698BFB /* MPParenthesisTerm.m */,
 				3B6338681A3A4C2B00698BFB /* MPPowerTerm.h */,
 				3B6338691A3A4C2B00698BFB /* MPPowerTerm.m */,
-				3B63389C1A3A4CEF00698BFB /* MPFractionTerm.h */,
-				3B63389D1A3A4CEF00698BFB /* MPFractionTerm.m */,
+				3B6338981A3A4CE100698BFB /* MPSumFunctionTerm.h */,
+				3B6338991A3A4CE100698BFB /* MPSumFunctionTerm.m */,
 			);
 			name = Functions;
 			sourceTree = "<group>";
@@ -598,7 +587,6 @@
 		3BF9977418DE623E009CF6C4 /* MathPad */ = {
 			isa = PBXGroup;
 			children = (
-				3BC4661819B3692A0033F13A /* Temp */,
 				3BF9978018DE623E009CF6C4 /* MPDocument.h */,
 				3BF9978118DE623E009CF6C4 /* MPDocument.m */,
 				3B87E353190082E200259938 /* Resources */,

MathPad/MPArrayCache.h

@@ -1,34 +0,0 @@
-//
-//  MPArrayCache.h
-//  MathPad
-//
-//  Created by Kim Wittenburg on 31.08.14.
-//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
-//
-
-#import <Foundation/Foundation.h>
-
-// A wrapper around NSCache to support index-based caches. Indexes are
-// automatically adjusted to represent array-like behaviours.
-@interface MPArrayCache : NSObject {
-    @private
-    NSCache *_cache;
-}
-
-- (id)init; /* designated initializer */
-
-- (void)cacheObject:(id)object
-           forIndex:(NSUInteger)index;
-- (id)cachedObjectForIndex:(NSUInteger)index;
-
-- (void)clearCacheAtIndex:(NSUInteger)index
-        replacementLength:(NSUInteger)replacementLength;
-- (void)clearCacheInRange:(NSRange)range
-        replacementLength:(NSUInteger)replacementLength;
-
-- (void)replaceCachedObjectAtIndex:(NSUInteger)index
-                       withObjects:(NSArray *)objects;
-- (void)replaceCachedObjectsInRange:(NSRange)range
-                        withObjects:(NSArray *)objects;
-
-@end

MathPad/MPArrayCache.m

@@ -1,59 +0,0 @@
-//
-//  MPArrayCache.m
-//  MathPad
-//
-//  Created by Kim Wittenburg on 31.08.14.
-//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
-//
-
-#import "MPArrayCache.h"
-
-@implementation MPArrayCache {
-    NSUInteger lastIndex;
-}
-
-- (instancetype)init
-{
-    self = [super init];
-    if (self) {
-        lastIndex = 0;
-        _cache = [[NSCache alloc] init];
-    }
-    return self;
-}
-
-- (void)cacheObject:(id)object
-           forIndex:(NSUInteger)index
-{
-    [_cache setObject:object
-               forKey:@(index)];
-    if (index > lastIndex) {
-        lastIndex = index;
-    }
-}
-
-- (id)cachedObjectForIndex:(NSUInteger)index
-{
-    return [_cache objectForKey:@(index)];
-}
-
-- (void)clearCacheAtIndex:(NSUInteger)index replacementLength:(NSUInteger)replacementLength
-{
-    [_cache removeObjectForKey:@(index)];
-    for (NSUInteger i = index+1; i < lastIndex; i++) {
-        id object = [_cache objectForKey:@(i)];
-        if (object) {
-            [_cache removeObjectForKey:@(i)];
-        }
-    }
-    lastIndex += replacementLength - 1;
-}
-
-- (void)clearCacheInRange:(NSRange)range replacementLength:(NSUInteger)replacementLength;
-
-- (void)replaceCachedObjectAtIndex:(NSUInteger)index
-                       withObjects:(NSArray *)objects;
-- (void)replaceCachedObjectsInRange:(NSRange)range
-                        withObjects:(NSArray *)objects;
-
-@end

MathPad/MPDocument.h

@@ -8,11 +8,39 @@
 
 #import <MathKit/MathKit.h>
 
+
+
+/*!
+    @class      MPDocument
+    @abstract   This class is the document class that displays the MathPad user
+                interface.
+ */
 @interface MPDocument : NSDocument
 
+
+/*!
+    @property   expressionView
+    @abstract   The main expression view.
+ */
 @property (weak) IBOutlet MPExpressionView *expressionView;
+
+
+/*!
+    @property   resultLabel
+    @abstract   The label which displays the result of the calculation.
+ 
+    @discussion The label is placed inside the expression view.
+ */
 @property (weak) IBOutlet NSTextField *resultLabel;
 
+
+/*!
+    @method     evaluateExpression:
+    @abstract   Called by the expression view when it should be evaluated.
+ 
+    @param      sender
+                Typically the object that invoked the method.
+ */
 - (IBAction)evaluateExpression:(id)sender;
 
 @end

MathPad/MPDocument.m

@@ -8,9 +8,11 @@
 
 #import "MPDocument.h"
 
-#import "MPParsedExpression.h"
 
-@implementation MPDocument
+
+@implementation MPDocument {
+    MPExpression *loadedExpression;
+}
 
 - (id)init
 {
@@ -21,46 +23,47 @@
     return self;
 }
 
+
 - (NSString *)windowNibName
 {
-    // Override returning the nib file name of the document
-    // If you need to use a subclass of NSWindowController or if your document supports multiple NSWindowControllers, you should remove this method and override -makeWindowControllers instead.
     return @"MPDocument";
 }
 
+
 - (void)windowControllerDidLoadNib:(NSWindowController *)aController
 {
     [super windowControllerDidLoadNib:aController];
     self.expressionView.target = self;
     self.expressionView.action = @selector(evaluateExpression:);
-    // Add any code here that needs to be executed once the windowController has loaded the document's window.
+    if (loadedExpression) {
+        [self.expressionView.expressionStorage appendElements:[loadedExpression allItemsInReferenceFrame:MPElementReferenceFrame]];
+    }
 }
 
+
 + (BOOL)autosavesInPlace
 {
     return YES;
 }
 
+
 - (NSData *)dataOfType:(NSString *)typeName error:(NSError **)outError
 {
-    // Insert code here to write your document to data of the specified type. If outError != NULL, ensure that you create and set an appropriate error when returning nil.
-    // You can also choose to override -fileWrapperOfType:error:, -writeToURL:ofType:error:, or -writeToURL:ofType:forSaveOperation:originalContentsURL:error: instead.
-    NSException *exception = [NSException exceptionWithName:@"UnimplementedMethod" reason:[NSString stringWithFormat:@"%@ is unimplemented", NSStringFromSelector(_cmd)] userInfo:nil];
-    @throw exception;
-    return nil;
+    return [NSKeyedArchiver archivedDataWithRootObject:self.expressionView.expressionStorage];
 }
 
+
 - (BOOL)readFromData:(NSData *)data ofType:(NSString *)typeName error:(NSError **)outError
 {
-    // Insert code here to read your document from the given data of the specified type. If outError != NULL, ensure that you create and set an appropriate error when returning NO.
-    // You can also choose to override -readFromFileWrapper:ofType:error: or -readFromURL:ofType:error: instead.
-    // If you override either of these, you should also override -isEntireFileLoaded to return NO if the contents are lazily loaded.
-    NSException *exception = [NSException exceptionWithName:@"UnimplementedMethod" reason:[NSString stringWithFormat:@"%@ is unimplemented", NSStringFromSelector(_cmd)] userInfo:nil];
-    @throw exception;
+    MPExpression *expression = [NSKeyedUnarchiver unarchiveObjectWithData:data];
+    loadedExpression = expression;
     return YES;
 }
 
+
 #pragma mark Actions
+
+
 - (IBAction)evaluateExpression:(id)sender {
     NSArray *errors;
     MPParsedExpression *parsedExpression = [self.expressionView.expressionStorage parse:&errors];
@@ -74,4 +77,5 @@
     self.resultLabel.stringValue = result != nil ? [result descriptionWithLocale:[NSLocale currentLocale]] : @"";
 }
 
+
 @end