| // Copyright 2015 The Bazel Authors. All rights reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #import "Equation.h" |
| |
| @implementation Equation { |
| NSMutableArray *_children; |
| } |
| |
| @synthesize operation = _operation; |
| |
| - (id)init { |
| [self doesNotRecognizeSelector:_cmd]; |
| return nil; |
| } |
| |
| - (id)initWithOperation:(Operation)operation { |
| self = [super init]; |
| if (self) { |
| _children = [NSMutableArray array]; |
| _operation = operation; |
| } |
| return self; |
| } |
| |
| - (NSArray *)children { |
| return [_children copy]; |
| } |
| |
| - (void)addExpressionAsChild:(Expression *)child { |
| [_children addObject:child]; |
| } |
| |
| - (double)calculate { |
| if ([_children count] == 1) { |
| return (_operation == kSubtract) |
| ? -[_children[0] calculate] : [_children[0] calculate]; |
| } else if ([_children count] == 0) { |
| return (_operation == kSubtract || _operation == kAdd) ? 0 : 1; |
| } |
| double value = [_children[0] calculate]; |
| for (Equation *child in [_children subarrayWithRange: |
| NSMakeRange(1, [_children count] - 1)]) { |
| double childValue = [child calculate]; |
| switch (_operation) { |
| case kAdd: |
| value += childValue; |
| break; |
| case kSubtract: |
| value -= childValue; |
| break; |
| case kMultiply: |
| value *= childValue; |
| break; |
| case kDivide: |
| value /= childValue; |
| break; |
| } |
| } |
| return value; |
| } |
| |
| - (NSString *)description { |
| NSMutableString *result = [[NSMutableString alloc] init]; |
| [result appendString:@"("]; |
| switch (_operation) { |
| case kAdd: |
| [result appendString:@"+"]; |
| break; |
| case kSubtract: |
| [result appendString:@"-"]; |
| break; |
| case kMultiply: |
| [result appendString:@"*"]; |
| break; |
| case kDivide: |
| [result appendString:@"/"]; |
| break; |
| } |
| for (Equation *child in _children) { |
| [result appendString:@" "]; |
| [result appendString:[child description]]; |
| } |
| [result appendString:@")"]; |
| return [result copy]; |
| } |
| |
| - (BOOL)isEqual:(id)object { |
| if (![object isKindOfClass:[self class]]) { |
| return NO; |
| } |
| Equation *other = object; |
| return other->_operation == _operation && |
| [other->_children isEqual:_children]; |
| } |
| |
| @end |