mathpad/MathPad/MPTerm.m

//
//  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"
#import "MPMathRules.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)initWithFactorialOfTerm:(MPTerm *)term
{
    return [self initWithBlock:^NSDecimalNumber *{
        NSDecimalNumber *termValue = [term evaluate];
        return [[NSDecimalNumber alloc] initWithDouble:tgamma(termValue.doubleValue + 1)];
    }];
}

- (instancetype)initWithSinOfTerm:(MPTerm *)term
{
    return [self initWithBlock:^NSDecimalNumber *{
        NSDecimalNumber *termValue = [term evaluate];
        if ([MPMathRules sharedRules].isUsingDegrees) {
            termValue = [[termValue decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithDouble:M_PI]] decimalNumberByDividingBy:[[NSDecimalNumber alloc] initWithInteger:180]];
        }
        return [[NSDecimalNumber alloc] initWithDouble:sin(termValue.doubleValue)];
    }];
}

- (instancetype)initWithCosOfTerm:(MPTerm *)term
{
    return [self initWithBlock:^NSDecimalNumber *{
        NSDecimalNumber *termValue = [term evaluate];
        if ([MPMathRules sharedRules].isUsingDegrees) {
            termValue = [[termValue decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithDouble:M_PI]] decimalNumberByDividingBy:[[NSDecimalNumber alloc] initWithInteger:180]];        }
        return [[NSDecimalNumber alloc] initWithDouble:cos(termValue.doubleValue)];
    }];
}

- (instancetype)initWithTanOfTerm:(MPTerm *)term
{
    return [self initWithBlock:^NSDecimalNumber *{
        NSDecimalNumber *termValue = [term evaluate];
        if ([MPMathRules sharedRules].isUsingDegrees) {
            termValue = [[termValue decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithDouble:M_PI]] decimalNumberByDividingBy:[[NSDecimalNumber alloc] initWithInteger:180]];        }
        return [[NSDecimalNumber alloc] initWithDouble:tan(termValue.doubleValue)];
    }];
}

- (instancetype)initWithInverseSinOfTerm:(MPTerm *)term
{
    return [self initWithBlock:^NSDecimalNumber *{
        NSDecimalNumber *termValue = [term evaluate];
        NSDecimalNumber *result = [[NSDecimalNumber alloc] initWithDouble:asin(termValue.doubleValue)];
        if ([MPMathRules sharedRules].isUsingDegrees) {
            result = [[result decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithInteger:180]] decimalNumberByDividingBy:[[NSDecimalNumber alloc] initWithDouble:M_PI]];
        }
        return result;
    }];
}

- (instancetype)initWithInverseCosOfTerm:(MPTerm *)term
{
    return [self initWithBlock:^NSDecimalNumber *{
        NSDecimalNumber *termValue = [term evaluate];
        NSDecimalNumber *result = [[NSDecimalNumber alloc] initWithDouble:acos(termValue.doubleValue)];
        if ([MPMathRules sharedRules].isUsingDegrees) {
            result = [[result decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithInteger:180]] decimalNumberByDividingBy:[[NSDecimalNumber alloc] initWithDouble:M_PI]];
        }
        return result;    }];
}

- (instancetype)initWithInverseTanOfTerm:(MPTerm *)term
{
    return [self initWithBlock:^NSDecimalNumber *{
        NSDecimalNumber *termValue = [term evaluate];
        NSDecimalNumber *result = [[NSDecimalNumber alloc] initWithDouble:atan(termValue.doubleValue)];
        if ([MPMathRules sharedRules].isUsingDegrees) {
            result = [[result decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithInteger:180]] decimalNumberByDividingBy:[[NSDecimalNumber alloc] initWithDouble:M_PI]];
        }
        return result;    }];
}

- (NSDecimalNumber *)evaluate
{
    @try {
        return self.block();
    }
    @catch (NSException *exception) {
        return [NSDecimalNumber notANumber];
    }
}

@end