Added the MPExpressionTree Classes

MathPad/MPProduct.m

@@ -0,0 +1,125 @@
+//
+//  MPProduct.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 09.10.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPProduct.h"
+#import "MPValueGroup.h"
+
+@implementation MPProduct {
+    NSMutableArray *_factors;
+    NSRange _range;
+}
+
+- (id)init
+{
+    self = [super init];
+    if (self) {
+        _factors = [[NSMutableArray alloc] init];
+    }
+    return self;
+}
+
+- (instancetype)initWithTokenStream:(MPTokenStream *)tokenStream
+{
+    self = [self init];
+    if (self) {
+        [tokenStream beginIgnoringWhitespaceTokens];
+        
+        MPTokenStreamRecordCurrentLocation(tokenStream);
+        while (tokenStream.currentToken.tokenType != MPOperatorListToken && tokenStream.currentToken.tokenType != MPEOFToken) {
+            [_factors addObject:[[MPFactor alloc] initWithTokenStream:tokenStream]];
+        }
+        _range = MPTokenStreamRecordedRange(tokenStream);
+        [tokenStream endIgnoringOrAcceptingWhitespaceTokens];
+    }
+    return self;
+}
+
+- (NSRange)range
+{
+    return _range;
+}
+
+- (BOOL)validate:(MPParseError *__autoreleasing *)error
+{
+    MPFactor *factor = _factors[0];
+    if (factor.hasMultiplicationSymbol) {
+        if (error) {
+            *error = MPParseError(factor.multiplicationSymbolRange, @"Unexpected Symbol.");
+        }
+    }
+    if (![factor.value validate:error]) {
+        return NO;
+    }
+    for (NSUInteger index = 1; index < _factors.count; index++) {
+        factor = _factors[index];
+        if (![factor validate:error]) {
+            return NO;
+        }
+    }
+    return YES;
+}
+
+- (NSDecimalNumber *)evaluate
+{
+    NSDecimalNumber *value = [NSDecimalNumber one];
+    for (MPFactor *factor in _factors) {
+        NSDecimalNumber *currentValue = [factor evaluate];
+        if ([currentValue isEqualToNumber:[NSDecimalNumber notANumber]]) {
+            value = currentValue;
+            break;
+        }
+        value = [value decimalNumberByMultiplyingBy:currentValue];
+        if ([value compare:@(0)] == NSOrderedSame) {
+            break;
+        }
+    }
+    return value;
+}
+
+- (NSArray *)expressionElements
+{
+    NSMutableArray *elements = [[NSMutableArray alloc] init];
+    for (MPFactor *factor in _factors) {
+        [elements addObjectsFromArray:factor.expressionElements];
+    }
+    return elements;
+}
+
+- (NSArray *)factors
+{
+    return _factors;
+}
+
+- (void)appendFactor:(MPFactor *)factor
+{
+    [_factors addObject:factor];
+}
+
+- (void)insertFactor:(MPFactor *)factor
+             atIndex:(NSUInteger)index
+{
+    [_factors insertObject:factor
+                   atIndex:index];
+}
+
+- (void)removeFactor:(MPFactor *)factor
+{
+    [_factors removeObject:factor];
+}
+
+- (void)removeFactorAtIndex:(NSUInteger)index
+{
+    [_factors removeObjectAtIndex:index];
+}
+
+- (MPFactor *)factorAtIndex:(NSUInteger)index
+{
+    return [_factors objectAtIndex:index];
+}
+
+@end