Drastic Simplification of MPFunction subclass implementations

MathPad/MPPowerFunction.m

@@ -0,0 +1,40 @@
+//
+//  MPPowerFunction.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 30.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPPowerFunction.h"
+#import "MPExpressionEvaluator.h"
+
+@implementation MPPowerFunction
+
+MPFunctionAccessorImplementation(ExponentExpression, _exponentExpression)
+
+- (NSArray *)childrenAccessors
+{
+    return @[@"exponentExpression"];
+}
+
+- (MPTerm *)parseWithError:(MPParseError *__autoreleasing *)error
+{
+    MPTerm *exponentTerm = [self.exponentExpression.evaluator parseExpectingVariable:NO
+                                                                               error:error];
+    if (exponentTerm == nil) {
+        return nil;
+    }
+    
+    return [[MPTerm alloc] initWithBlock:^NSDecimalNumber *{
+        double power = pow([self.baseTerm evaluate].doubleValue, [exponentTerm evaluate].doubleValue);
+        return [[NSDecimalNumber alloc] initWithDouble:power];
+    }];
+}
+
+- (NSString *)description
+{
+    return [NSString stringWithFormat:@"^%@", self.exponentExpression.description];
+}
+
+@end