Added the MPExpressionTree Classes

MathPad/MPExpressionTreeElement.h

@@ -0,0 +1,30 @@
+//
+//  MPExpressionTreeElement.h
+//  MathPad
+//
+//  Created by Kim Wittenburg on 09.10.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+#import "MPTokenStream.h"
+#import "MPParseError.h"
+#import "MPTokenStream.h"
+
+#define MPTokenStreamRecordCurrentLocation(tokenStream) NSUInteger __tokenStreamStart = tokenStream.currentToken.range.location
+#define MPTokenStreamRecordedRange(tokenStream) NSMakeRange(__tokenStreamStart, tokenStream.currentToken.range.location - __tokenStreamStart)
+
+@protocol MPExpressionTreeElement <NSObject>
+@required
+
+- (instancetype)init;
+- (instancetype)initWithTokenStream:(MPTokenStream *)tokenStream;
+
+- (NSRange)range;
+
+- (BOOL)validate:(MPParseError *__autoreleasing *)error;
+- (NSDecimalNumber *)evaluate;
+
+- (NSArray *)expressionElements; // Converts
+
+@end