Implemented Expression Evaluation/Parsing with Proper Error Handling

MathPad/MPParsedFactor.m

@@ -0,0 +1,60 @@
+//
+//  MPParsedFactor.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 10.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPParsedFactor.h"
+
+@implementation MPParsedFactor {
+    NSDecimalNumber *_value;
+}
+
++ (MPParsedFactor *)factorWithDecimalNumber:(NSDecimalNumber *)number
+{
+    return [[MPParsedFactor alloc] initWithDecimalNumber:number];
+}
+
++ (MPParsedFactor *)sinFactorWithFactor:(MPParsedFactor *)factor
+{
+    double value = factor.value.doubleValue;
+    NSDecimalNumber *actualNumber = [[NSDecimalNumber alloc] initWithDouble:sin(value)];
+    return [[MPParsedFactor alloc] initWithDecimalNumber:actualNumber];
+}
+
++ (MPParsedFactor *)cosFactorWithFactor:(MPParsedFactor *)factor
+{
+    double value = factor.value.doubleValue;
+    NSDecimalNumber *actualNumber = [[NSDecimalNumber alloc] initWithDouble:cos(value)];
+    return [[MPParsedFactor alloc] initWithDecimalNumber:actualNumber];
+}
+
++ (MPParsedFactor *)tanFactorWithFactor:(MPParsedFactor *)factor
+{
+    double value = factor.value.doubleValue;
+    NSDecimalNumber *actualNumber = [[NSDecimalNumber alloc] initWithDouble:tan(value)];
+    return [[MPParsedFactor alloc] initWithDecimalNumber:actualNumber];
+}
+
+- (instancetype)initWithDecimalNumber:(NSDecimalNumber *)number
+{
+    self = [super init];
+    if (self) {
+        _value = number;
+    }
+    return self;
+}
+
+- (NSDecimalNumber *)value
+{
+    return _value;
+}
+
+- (NSString *)description
+{
+    return [NSString stringWithFormat:@"MPParsedFactor<%@>", _value];
+}
+
+@end