Improved Evaluation

MathPad/MPTerm.m

@@ -0,0 +1,94 @@
+//
+//  MPTerm.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 27.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPTerm.h"
+#import "MPEvaluationContext.h"
+
+@interface MPTerm ()
+
+@property (nonatomic, copy) NSDecimalNumber *(^block)();
+
+@end
+
+@implementation MPTerm
+
+- (instancetype)initWithBlock:(NSDecimalNumber *(^)())block
+{
+    self = [super init];
+    if (self) {
+        self.block = block;
+    }
+    return self;
+}
+
+- (instancetype)initWithNumber:(NSDecimalNumber *)number
+{
+    return [self initWithBlock:^NSDecimalNumber *{
+        return number;
+    }];
+}
+
+- (instancetype)initWithSummands:(NSArray *)summands
+{
+    return [self initWithBlock:^NSDecimalNumber *{
+        NSDecimalNumber *value = [NSDecimalNumber zero];
+        for (MPTerm *term in summands) {
+            value = [value decimalNumberByAdding:[term evaluate]];
+        }
+        return value;
+    }];
+}
+
+- (instancetype)initWithFactors:(NSArray *)factors
+{
+    return [self initWithBlock:^NSDecimalNumber *{
+        NSDecimalNumber *value = [NSDecimalNumber one];
+        for (MPTerm *term in factors) {
+            value = [value decimalNumberByMultiplyingBy:[term evaluate]];
+        }
+        return value;
+    }];
+}
+
+- (instancetype)initWithVariable:(NSString *)variable
+{
+    return [self initWithBlock:^NSDecimalNumber *{
+        return [[MPEvaluationContext sharedContext] valueForVariable:variable];
+    }];
+}
+
+- (instancetype)initWithSinOfTerm:(MPTerm *)term
+{
+    return [self initWithBlock:^NSDecimalNumber *{
+        NSDecimalNumber *sinValue = [term evaluate];
+        return [[NSDecimalNumber alloc] initWithDouble:sin(sinValue.doubleValue)];
+    }];
+}
+
+- (instancetype)initWithCosOfTerm:(MPTerm *)term
+{
+    return [self initWithBlock:^NSDecimalNumber *{
+        NSDecimalNumber *cosValue = [term evaluate];
+        return [[NSDecimalNumber alloc] initWithDouble:cos(cosValue.doubleValue)];
+    }];
+}
+
+- (instancetype)initWithTanOfTerm:(MPTerm *)term
+{
+    return [self initWithBlock:^NSDecimalNumber *{
+        NSDecimalNumber *tanValue = [term evaluate];
+        return [[NSDecimalNumber alloc] initWithDouble:tan(tanValue.doubleValue)];
+    }];
+}
+
+- (NSDecimalNumber *)evaluate
+{
+    return self.block();
+}
+
+@end