/* Tokenizer interface. See implementation for details */

public interface Tokenizer {
	/**
	 * This is the integer token. An integer is
	 * defined as a sequence of digits starting
	 * with either a dash or a digit and containing
	 * only digits after the first digit
	 */
	int INTEGER = -1;
	
	/**
	 * This is the float token. A float is defined
	 * as a sequence of digits starting with either a
	 * dash, a period, or a digit and containing only
	 * digits and one period after the first digit.
	 */
	int FLOAT = -2;

	/**
	 * Ths is the word token. A word is defined a letter
	 * followed by a sequence of alphanumeric characters
	 * or underscores (_) without any whitespace. It may
	 * also include a color (:), but this is the termination
	 * of the word. Also, a word is anything between two
	 * quotation signs. Valid escapes (\n, \r. \\, \". etc...)
	 * should also be evaluated in this case.
	 * Finally, if a string such as 2.0.0 is detected,
	 * this should also be considered a word.
	 */
	int WORD = -3;
	
	/**
	 * This is the operator token. The operator token is defined
	 * as any non alphanumeric character and should be represented
	 * by the java type char
	 */
	int OPERATOR = -4;

	/**
	 * This is the end-of-file token. Such a token represents that
	 * end of the stream has been reached and there exist no more
	 * tokens.
	 */
	int EOF = -5;

	/**
	 * Returns the type of the next token
	 */
	int peekAtKind() throws TokenizerException;
	/**
	 * Returns the next token (unless its not an integer)
	 * @throws TokenizerException if the next token is not an integer
	 */
	int getInt() throws TokenizerException;
	/**
	 * Returns the next token (unless its not a float)
	 * @throws TokenizerException if the next token is not a float
	 */
	float getFloat() throws TokenizerException;
	/**
	 * Returns the next token (unless its not a word)
	 * @throws TokenizerException if the next token is not a word
	 */
	String getWord() throws TokenizerException;
	/**
	 * Returns the next token (unless its not an operator)
	 * @throws TokenizerException if the next token is not an operator
	 */
	char getOp() throws TokenizerException;
	/**
	 * Matches the next character if its a character or throws TokenizerException
	 * @param c the character to match
	 * @throws TokenizerException if the next token is not c
	 */
	void match(char c) throws TokenizerException;
	/**
	 * Matches the next character if its a word or throws TokenizerException
	 * @param s the word to match
	 * @throws TokenizerException if the next token is not s
	 */
	void match(String s) throws TokenizerException;
	/**
	 * Checks if the next token is a character/operator and is c
	 * @param c the value to check against
	 * @return true if the next token is c, false otherwise
	 */
	boolean check(char c);
	/**
	 * Checks if the next token is the word s
	 * @param s the value to check against
	 * @return true if the next token is s, false otherwise
	 */
	boolean check(String s);
	/**
	 * Pushes the latest token requested back. Check individual
	 * implementations as to the effectiveness of this
	 */
	void pushBack();
	/**
	 * Returns the line number
	 */
	int lineNo();
	/**
	 * Closes the tokenizer
	 * @throws TokenizerException if there is an I/O Error
	 */
	void close() throws TokenizerException;
}