import java.util.StringTokenizer;

/**
 * Implements the lexical analysis of our programs.  The
 * implementation uses a StringTokenizer from Java's library.
 *
 * @author Marcel Turcotte
 */

class Reader {

    // instance variable

    private StringTokenizer st;

    /**
     * Create a Reader object for the parameter string.
     */

    Reader( String s ) {
	st = new StringTokenizer( s );
    }

    /**
     * Tests if the end of the program has been reached.
     *
     * @return true if the Reader has reached the end of the input (program).
     */

    public boolean hasMoreTokens() {
	return st.hasMoreTokens();
    }

    /**
     * Reads and returns the next token.
     *
     * @return The next Token from the input.
     */

    public Token nextToken() {

	String t = st.nextToken();

	try {
	    return new Token( Integer.parseInt( t ) );
	} catch ( NumberFormatException e ) { 
	    return new Token( t );
	}
	
    }

}