/*
 * expressionTree.h
 *
 * type definitions for supporting the expression tree.
 *
 */


#ifndef _EXPRESSIONTREE_H_
#define _EXPRESSIONTREE_H_


enum OperandType {Cell, Literal};

typedef struct CellToken {
	int column;	// column A = 0, B = 1, etc.
	int row;
} CellToken;

typedef struct OperandToken {
	OperandType opType;
	int literalID;	        // valid if opType == Literal
	CellToken cellID;		// valid if opType == Cell
} OperandToken;

enum OperatorToken {Plus, Minus, Mult, Div, LeftParen, Error};

enum TokenType {OperatorTokenType, CellTokenType, LiteralTokenType};

typedef struct ExpressionTreeToken {
	TokenType tokenType;
	CellToken cellID;		// valid if tokenType == CellTokenType
	OperatorToken operatorToken;	// valid if tokenType == OperatorTokenType
	int literalID;	        // valid if tokenType == LiteralTokenType
} ExpressionTreeToken;


class ExpressionTreeNode {
	ExpressionTreeToken token;
	ExpressionTreeNode *left;
	ExpressionTreeNode *right;

	friend class ExpressionTree;
};


class ExpressionTree {
public:
    // You will have to write functions that work on
    // ExpressionTree.  Here are some examples:
	// void makeEmpty();
	// void printTree();
	// int Evaluate(Spreadsheet & spreadsheet);
private:
	ExpressionTreeNode *root;
};


#endif // _EXPRESSIONTREE_H