codello/mathpad
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Added Evaluation Context and Math Rules

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This commit is contained in:
Kim Wittenburg
2014-09-15 15:58:35 +02:00
parent 6573cd1b5c
commit 3cf2006af7
6 changed files with 191 additions and 41 deletions
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90
MathPad/MPElementParser.m
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@@ -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 Creation Methods
+ (void)initialize
#pragma mark Helpers
- (BOOL)allowsImplicitMultiplication
{
useUserDefaults = YES;
return [MPMathRules sharedRules].allowsImplicitMultiplication;
}
- (instancetype)init
- (BOOL)maximumOperatorChainLength
{
self = [super init];
if (self) {
self.allowsImplicitMultiplications = NO;
self.maximumOperatorChainLength = 2;
self.maximumOperatorChainLengthInMultiplication = 1;
}
return self;
return [MPMathRules sharedRules].maximumOperatorChainLength;
}
#pragma mark Properties
+ (BOOL)isUsingDefaultValuesFromUserDefaults
- (BOOL)maximumOperatorChainLengthInFunction
{
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) {
NSLog(@"Here I am");
} else if (self.allowsImplicitMultiplication) {
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];
} else if (self.allowsImplicitMultiplications) {
[currentProduct addFactor:number];
currentProduct = [[MPParsedProduct alloc] initWithFactor:value];
} else if (self.allowsImplicitMultiplication) {
[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