question: public void nextToken ( ) { previousLine = line ; previousColumn = column ; while ( pos < matcher . regionStart ( ) ) { if ( text . charAt ( pos ) == '\n' ) { ++ line ; column = 0 ; } else { ++ column ; } ++ pos ; } if ( matcher . regionStart ( ) == matcher . regionEnd ( ) ) { currentToken = "" ; } else { matcher . usePattern ( TOKEN ) ; if ( matcher . lookingAt ( ) ) { currentToken = matcher . group ( ) ; matcher . region ( matcher . end ( ) , matcher . regionEnd ( ) ) ; } else { currentToken = String . valueOf ( text . charAt ( pos ) ) ; matcher . region ( pos + 1 , matcher . regionEnd ( ) ) ; } skipWhitespace ( ) ; } }
target:  Advance to the next token. 