Added Evaluation Context and Math Rules

MathPad/MPElementParser.h

@@ -14,15 +14,6 @@
 
 @interface MPElementParser : NSObject
 
-+ (BOOL)isUsingDefaultValuesFromUserDefaults;
-+ (void)setUsingDefaultValuesFromUserDefaults:(BOOL)flag;
-
-@property (nonatomic) BOOL allowsImplicitMultiplications; // wether 2 3 is equal to 6 or error
-// 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 (nonatomic) NSUInteger maximumOperatorChainLengthInFunction; // For sin, cos, tan. Default: 1
-
 - (NSArray *)parseElement:(NSString *)string
           previousProduct:(MPParsedProduct *)previousProduct
                nextFactor:(id<MPParsedFactor>)nextFactor

MathPad/MPElementParser.m

@@ -8,6 +8,7 @@
 
 #import "MPElementParser.h"
 #import "NSRegularExpression+MPParsingAdditions.h"
+#import "MPMathRules.h"
 
 #import "MPParsedFactor.h"
 #import "MPParsedNumber.h"
@@ -21,6 +22,11 @@
 @property (nonatomic) NSString *input;
 @property (nonatomic) NSUInteger parsePosition;
 
+- (BOOL)allowsImplicitMultiplication;
+- (BOOL)maximumOperatorChainLength;
+- (BOOL)maximumOperatorChainLengthInMultiplication;
+- (BOOL)maximumOperatorChainLengthInFunction;
+
 - (void)setError:(MPParseError *)error;
 
 - (BOOL)isAtEnd;
@@ -30,7 +36,9 @@
 - (NSRange)parseWhitespaces;
 - (NSRange)parseMultiplicationSymbol;
 - (MPParsedOperator *)parseOperators;
+- (id<MPParsedFactor>)parseValue;
 - (MPParsedNumber *)parseNumber;
+- (MPParsedVariable *)parseVariable;
 
 @end
 
@@ -38,36 +46,25 @@
     MPParseError *__autoreleasing *outError;
 }
 
-static BOOL useUserDefaults;
+#pragma mark Helpers
-
+- (BOOL)allowsImplicitMultiplication
-#pragma mark Creation Methods
-
-+ (void)initialize
 {
-    useUserDefaults = YES;
+    return [MPMathRules sharedRules].allowsImplicitMultiplication;
 }
 
-- (instancetype)init
+- (BOOL)maximumOperatorChainLength
 {
-    self = [super init];
+    return [MPMathRules sharedRules].maximumOperatorChainLength;
-    if (self) {
-        self.allowsImplicitMultiplications = NO;
-        self.maximumOperatorChainLength = 2;
-        self.maximumOperatorChainLengthInMultiplication = 1;
-    }
-    return self;
 }
 
-#pragma mark Properties
+- (BOOL)maximumOperatorChainLengthInFunction
-
-+ (BOOL)isUsingDefaultValuesFromUserDefaults
 {
-    return useUserDefaults;
+    return [MPMathRules sharedRules].maximumOperatorChainLengthInFunction;
 }
 
-+ (void)setUsingDefaultValuesFromUserDefaults:(BOOL)flag
+- (BOOL)maximumOperatorChainLengthInMultiplication
 {
-    useUserDefaults = flag;
+    return [MPMathRules sharedRules].maximumOperatorChainLengthInMultiplication;
 }
 
 #pragma mark Parsing Methods
@@ -136,10 +133,10 @@ static BOOL useUserDefaults;
         // NSRange functionRange = ...
         // BOOL hasFunction = functionRange.location != NSNotFound;
 
-        MPParsedNumber *number = [self parseNumber];
+        id<MPParsedFactor> value = [self parseValue];
         
         
-        if (!number.exists) {
+        if (!value.exists) {
             if ([self isAtEnd] && nextFactor != nil) {
                 if (hasMultiplicationSymbol) {
                     if (operators.numberOfOperators > self.maximumOperatorChainLengthInFunction) {
@@ -155,13 +152,11 @@ static BOOL useUserDefaults;
                     [products addObject:currentProduct];
                     currentProduct = [[MPParsedProduct alloc] init];
                     [currentProduct addFactor:operators];
-                } else if (self.allowsImplicitMultiplications) {
+                } else if (self.allowsImplicitMultiplication) {
-                    NSLog(@"Here I am");
                     if (!currentProduct) {
                         currentProduct = [[MPParsedProduct alloc] init];
                     }
                 } else {
-                    NSLog(@"ERR");
                     self.error = MPParseError(NSMakeRange(self.parsePosition, 0), @"Implicit Multiplication not allowed.");
                     return nil;
                 }
@@ -184,7 +179,7 @@ static BOOL useUserDefaults;
                         return nil;
                     }
                     [currentProduct addFactor:operators];
-                    [currentProduct addFactor:number];
+                    [currentProduct addFactor:value];
                 } else {
                     self.error = MPParseError(multiplicationSymbolRange, @"Unexpected Symbol. Expected Number.");
                     return nil;
@@ -198,13 +193,13 @@ static BOOL useUserDefaults;
                     [products addObject:currentProduct];
                 }
                 currentProduct = [[MPParsedProduct alloc] initWithFactor:operators];
-                [currentProduct addFactor:number];
+                [currentProduct addFactor:value];
             } else if (!currentProduct) {
-                currentProduct = [[MPParsedProduct alloc] initWithFactor:number];
+                currentProduct = [[MPParsedProduct alloc] initWithFactor:value];
-            } else if (self.allowsImplicitMultiplications) {
+            } else if (self.allowsImplicitMultiplication) {
-                [currentProduct addFactor:number];
+                [currentProduct addFactor:value];
             } else {
-                self.error = MPParseError(NSMakeRange(number.range.location, 0), @"Implicit Multiplication not allowed.");
+                self.error = MPParseError(NSMakeRange(value.range.location, 0), @"Implicit Multiplication not allowed.");
                 return nil;
             }
         }
@@ -294,6 +289,18 @@ static NSRegularExpression *operatorsRegex;
                                           inString:self.input];
 }
 
+- (id<MPParsedFactor>)parseValue
+{
+    MPParsedNumber *parsedNumber = [self parseNumber];
+    if (!parsedNumber.exists) {
+        MPParsedVariable *parsedVariable = [self parseVariable];
+        if (parsedVariable.exists) {
+            return parsedVariable;
+        }
+    }
+    return parsedNumber;
+}
+
 - (MPParsedNumber *)parseNumber
 {
     NSString *decimalSeparatorRegexString = [NSRegularExpression escapedPatternForString:[[NSLocale currentLocale] objectForKey:NSLocaleDecimalSeparator]];
@@ -314,4 +321,25 @@ static NSRegularExpression *operatorsRegex;
                                         inString:self.input];
 }
 
+static NSRegularExpression *variableRegex;
+- (MPParsedVariable *)parseVariable
+{
+    if (!variableRegex) {
+        variableRegex = [NSRegularExpression regularExpressionWithPattern:@"\\A\\s*([A-Za-z])\\s*"
+                                                                  options:0
+                                                                    error:NULL];
+    }
+    NSTextCheckingResult *match = [variableRegex firstMatchInString:self.input
+                                                          fromIndex:self.parsePosition];
+    NSRange matchRange;
+    if (!match) {
+        matchRange = NSMakeRange(NSNotFound, 0);
+    } else {
+        self.parsePosition = NSMaxRange(match.range);
+        matchRange = [match rangeAtIndex:1];
+    }
+    return [[MPParsedVariable alloc] initWithRange:matchRange
+                                          inString:self.input];
+}
+
 @end

MathPad/MPEvaluationContext.m

@@ -25,6 +25,9 @@ static MPEvaluationContext *sharedContext;
 
 - (instancetype)init
 {
+    if (sharedContext) {
+        return sharedContext;
+    }
     self = [super init];
     if (self) {
         _stack = [[NSMutableArray alloc] init];

MathPad/MPExpressionEvaluator.m

@@ -11,6 +11,7 @@
 #import "MPFunction.h"
 #import "MPParsedFactor.h"
 #import "MPFunction+MPParsedFactor.h"
+#import "MPMathRules.h"
 
 @interface MPExpressionEvaluator ()
 @property (readwrite, nonatomic, strong) NSString *definedVariable;
@@ -87,8 +88,12 @@
         } else {
             if (!currentProduct) {
                 currentProduct = [[MPParsedProduct alloc] init];
-            }
+            } else if ([MPMathRules sharedRules].allowsImplicitMultiplication) {
                 [currentProduct addFactor:(MPFunction *)element];
+            } else {
+                *error = MPParseError(NSMakeRange(((MPFunction *)element).range.location, 0), @"Implicit Multiplication not allowed");
+                return nil;
+            }
         }
     }
     

MathPad/MPMathRules.h

@@ -0,0 +1,28 @@
+//
+//  MPMathRules.h
+//  MathPad
+//
+//  Created by Kim Wittenburg on 14.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+FOUNDATION_EXPORT NSString *MPMathRulesAllowsImplicitMultiplicationKey;
+FOUNDATION_EXPORT NSString *MPMathRulesMaximumOperatorChainLengthKey;
+FOUNDATION_EXPORT NSString *MPMathRulesMaximumOperatorChainLengthInMultiplicationKey;
+FOUNDATION_EXPORT NSString *MPMathRulesMaximumOperatorChainLengthInFunctionKey;
+
+@interface MPMathRules : NSObject
+
++ (MPMathRules *)sharedRules;
+
+@property (nonatomic, getter = isUsingUserDefaultValues) BOOL usingUserDefaultValues;
+
+@property (nonatomic) BOOL allowsImplicitMultiplication; // wether 2 3 is equal to 6 or error
+// 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 (nonatomic) NSUInteger maximumOperatorChainLengthInFunction; // For sin, cos, tan. Default: 1
+
+@end

MathPad/MPMathRules.m

@@ -0,0 +1,95 @@
+//
+//  MPMathRules.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 14.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPMathRules.h"
+
+NSString *MPMathRulesAllowsImplicitMultiplicationKey = @"MPMathRulesAllowsImplicitMultiplicationKey";
+NSString *MPMathRulesMaximumOperatorChainLengthKey = @"MPMathRulesMaximumOperatorChainLengthKey";
+NSString *MPMathRulesMaximumOperatorChainLengthInMultiplicationKey = @"MPMathRulesMaximumOperatorChainLengthInMultiplicationKey";
+NSString *MPMathRulesMaximumOperatorChainLengthInFunctionKey = @"MPMathRulesMaximumOperatorChainLengthInFunctionKey";
+
+@implementation MPMathRules
+
+static MPMathRules *sharedRules;
+
++ (MPMathRules *)sharedRules
+{
+    if (!sharedRules) {
+        sharedRules = [[MPMathRules alloc] init];
+    }
+    return sharedRules;
+}
+
+- (instancetype)init
+{
+    if (sharedRules) {
+        return sharedRules;
+    }
+    self = [super init];
+    if (self) {
+        _usingUserDefaultValues = YES;
+        NSNumber *userDefaultsAllowImplicitMultiplication = [[NSUserDefaults standardUserDefaults] objectForKey:MPMathRulesAllowsImplicitMultiplicationKey];
+        NSNumber *userDefaultsMaximumOperatorChainLength = [[NSUserDefaults standardUserDefaults] objectForKey:MPMathRulesMaximumOperatorChainLengthKey];
+        NSNumber *userDefaultsMaximumOperatorChainLengthInMultiplication = [[NSUserDefaults standardUserDefaults] objectForKey:MPMathRulesMaximumOperatorChainLengthInMultiplicationKey];
+        NSNumber *userDefaultsMaximumOperatorChainLengthInFunction = [[NSUserDefaults standardUserDefaults] objectForKey:MPMathRulesMaximumOperatorChainLengthInFunctionKey];
+        
+        _allowsImplicitMultiplication = userDefaultsAllowImplicitMultiplication != nil ? userDefaultsAllowImplicitMultiplication.boolValue : NO;
+        _maximumOperatorChainLength = userDefaultsMaximumOperatorChainLength != nil ? userDefaultsMaximumOperatorChainLength.unsignedIntegerValue : 2;
+        _maximumOperatorChainLengthInMultiplication = userDefaultsMaximumOperatorChainLengthInMultiplication != nil ? userDefaultsMaximumOperatorChainLengthInMultiplication.unsignedIntegerValue : 1;
+        _maximumOperatorChainLengthInFunction = userDefaultsMaximumOperatorChainLengthInFunction != nil ? userDefaultsMaximumOperatorChainLengthInFunction.unsignedIntegerValue : 1;
+    }
+    return self;
+}
+
+- (void)setUsingUserDefaultValues:(BOOL)usingUserDefaultValues
+{
+    _usingUserDefaultValues = usingUserDefaultValues;
+    // Save the current values
+    self.allowsImplicitMultiplication = self.allowsImplicitMultiplication;
+    self.maximumOperatorChainLength = self.maximumOperatorChainLength;
+    self.maximumOperatorChainLengthInMultiplication = self.maximumOperatorChainLengthInMultiplication;
+    self.maximumOperatorChainLengthInFunction = self.maximumOperatorChainLengthInFunction;
+}
+
+- (void)setAllowsImplicitMultiplication:(BOOL)allowsImplicitMultiplication
+{
+    _allowsImplicitMultiplication = allowsImplicitMultiplication;
+    if (self.isUsingUserDefaultValues) {
+        [[NSUserDefaults standardUserDefaults] setBool:allowsImplicitMultiplication
+                                                forKey:MPMathRulesAllowsImplicitMultiplicationKey];
+    }
+}
+
+- (void)setMaximumOperatorChainLength:(NSUInteger)maximumOperatorChainLength
+{
+    _maximumOperatorChainLength = maximumOperatorChainLength;
+    if (self.isUsingUserDefaultValues) {
+        [[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithUnsignedInteger:maximumOperatorChainLength]
+                                                  forKey:MPMathRulesMaximumOperatorChainLengthKey];
+    }
+}
+
+- (void)setMaximumOperatorChainLengthInMultiplication:(NSUInteger)maximumOperatorChainLengthInMultiplication
+{
+    _maximumOperatorChainLengthInMultiplication = maximumOperatorChainLengthInMultiplication;
+    if (self.isUsingUserDefaultValues) {
+        [[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithUnsignedInteger:maximumOperatorChainLengthInMultiplication]
+                                                  forKey:MPMathRulesMaximumOperatorChainLengthInMultiplicationKey];
+    }
+}
+
+- (void)setMaximumOperatorChainLengthInFunction:(NSUInteger)maximumOperatorChainLengthInFunction
+{
+    _maximumOperatorChainLengthInFunction = maximumOperatorChainLengthInFunction;
+    if (self.isUsingUserDefaultValues) {
+        [[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithUnsignedInteger:maximumOperatorChainLengthInFunction]
+                                                  forKey:MPMathRulesMaximumOperatorChainLengthInFunctionKey];
+    }
+}
+
+@end