Added the MPExpressionTree Classes

MathPad/MPValueGroup.h

@@ -0,0 +1,34 @@
+//
+//  MPValueGroup.h
+//  MathPad
+//
+//  Created by Kim Wittenburg on 09.10.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+#import "MPExpressionTreeElement.h"
+
+@protocol MPValue <MPExpressionTreeElement>
+
+@end
+
+
+@interface MPValueGroup : NSObject <MPValue>
+
+@property (nonatomic, strong) NSArray *values;
+- (void)appendValue:(id<MPValue>)value;
+- (void)insertValue:(id<MPValue>)value
+              atIndex:(NSUInteger)index;
+- (void)removeValue:(id<MPValue>)value;
+- (void)removeValueAtIndex:(NSUInteger)index;
+- (id<MPValue>)valueAtIndex:(NSUInteger)index;
+
+@end
+
+
+@interface MPTokenStream (MPValueSuffixes)
+
+- (id<MPValue>)consumeSuffixesForValue:(id<MPValue>)value;
+
+@end