Added Lots of Documentation

Added some nice to haves
Improved and Unified General Code Layout

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];