//
//  MPFunction.h
//  MathPad
//
//  Created by Kim Wittenburg on 18.04.14.
//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
//

@class MPFunction, MPExpression;

@interface MPFunction : NSObject <NSCopying, NSCoding>

#pragma mark Creation Methods

- (instancetype)init;

#pragma mark Working With the Expression Tree

@property (nonatomic, weak) MPExpression *parent; // Documentation: Do not set

- (NSUInteger)numberOfChildren;
- (MPExpression *)childAtIndex:(NSUInteger)index;
- (void)setChild:(MPExpression *)child
         atIndex:(NSUInteger)index;

#pragma mark Evaluating Functions

- (double)doubleValue;

#pragma mark Working With Functions

- (BOOL)isEqualToFunction:(MPFunction *)aFunction;

@end

@interface MPFunction (MPFunctionExtensionMethods)

#pragma mark Working With the Expression Tree

// May be overridden for performance improvements
- (NSArray *)children;
- (NSUInteger)indexOfChild:(MPExpression *)child;

- (id)symbolAtIndexPath:(NSIndexPath *)indexPath;

#pragma mark Evaluating Functions

- (float)floatValue;
- (int)intValue;
- (NSInteger)integerValue;
- (long long)longLongValue;

- (NSString *)description;

- (NSUInteger)hash;

@end