//
//  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
{
    MPExpressionEvaluator *exponent = [[MPExpressionEvaluator alloc] initWithExpression:self.exponentExpression];
    MPTerm *exponentTerm = [exponent 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