/**
* Each Token object represents one token from the compiler input stream.
*/
public class Token {
	/**
	* Construct a new Token with no attributes except its type.
	* @param t the token type, one of the types defined by the Token class.
	*/
	public Token(int t) {
		type = t;
	}
	/**
	* Construct a new Token with an associated
	* String attribute.
	* @param t the token type (probably Token.ID).
	* @param s the value of the String attribute for this token
	*/
	public Token(int t,String s) {
		type = t;
		label = s;
	}
	/**
	* Construct a new Token with an associated
	* integer value attribute.
	* @param t the token type (probably Token.INTEGER).
	* @param v the integer value of the numeric attribute for this token
	*/
	public Token(int t,int v) {
		type = t;
		value = new Integer(v);
	}
	/**
	* Construct a new Token with an associated
	* real value attribute.
	* @param t the token type (probably Token.REAL).
	* @param v the double value of the numeric attribute for this token
	*/
	public Token(int t,double v) {
		type = t;
		value = new Double(v);
	}
	/**
	* Get the type of this Token.
	* @return the Token type
	*/
	public int getType() {
		return type;
	}
	/**
	* Get the String attribute of this object.
	* @return the Token string
	*/
	public String getLabel() {
		return label;
	}
	/**
	* Get the numeric attribute of this token as an int value.
	* @return the value of the numeric attribute of this token as an int value
	*/
	public int getIntValue() {
		return value.intValue();
	}
	/**
	* Get the numeric attribute of this token as a double value.
	* @return the value of the numeric attribute of this token as a double value
	*/
	public double getDoubleValue() {
		return value.doubleValue();
	}
	/**
	* Provide the String that describes this Token.
	*/
	public String toString() {
		String s = tokenTypes[type];
		if (type == Token.ID) {
			s += "("+label+")";
		} else if (type == Token.INTEGER || type == Token.REAL) {
			s += "("+value.toString()+")";
		}
		return s;
	}
	/**
	* Provide the String that describes this Token type.
	* @param type the Token type to be described.  Must be a valid
	* (defined) Token type, or a runtime Exception will occur.
	* @return the String the describes this Token type.
	*/
	public static String typeLabel(int type) {
		return tokenTypes[type];
	}
	
	//--------------------------------------------------
	
	private int type;
	private Number value;
	private String label;
	
	//--------------------------------------------------
	
	/** The token types as Strings for use in toString.  The index of
	 * each string must match the Token type so that it gets displayed correctly. 
	 */
	private static String[] tokenTypes = {
	"EOF",			"LPAREN",		"RPAREN",		"LCURLY",	"RCURLY",
	"DOT",			"COMMA",		"SEMICOLON",	"COLON",
	"ID",			"INTEGER",		"REAL",
	"OP_ASSIGN",	"OP_NOT",		"OP_EQ",		"OP_LT",	"OP_GT",
	"OP_ADD",		"OP_SUB",		"OP_MUL",		"OP_DIV",
	"KW_IF",		"KW_ELSE",		"KW_PROLOG",	"KW_MOVIE",	"KW_SHOW"
	};
	
	public static final int EOF			= 0;
	public static final int LPAREN		= 1;
	public static final int RPAREN		= 2;
	public static final int LCURLY		= 3;
	public static final int RCURLY		= 4;
	public static final int DOT			= 5;
	public static final int COMMA		= 6;
	public static final int SEMICOLON	= 7;
	public static final int COLON		= 8;
	public static final int ID			= 9;
	public static final int INTEGER		= 10;
	public static final int REAL		= 11;
	public static final int OP_ASSIGN	= 12;
	public static final int OP_NOT		= 13;
	public static final int OP_EQ		= 14;
	public static final int OP_LT		= 15;
	public static final int OP_GT		= 16;
	public static final int OP_ADD		= 17;
	public static final int OP_SUB		= 18;
	public static final int OP_MUL		= 19;
	public static final int OP_DIV		= 20;
	public static final int KW_IF		= 21;
	public static final int KW_ELSE		= 22;
	public static final int KW_PROLOG	= 23;
	public static final int KW_MOVIE	= 24;
	public static final int KW_SHOW		= 25;
}