%%

%class lexer
%cup 
%char
%line
%eofval{
   return new Token (sym.EOF, null);
%eofval}
%yylexthrow{
   Exception
%yylexthrow}

WHITESPACE = [\ \t\r\n]+
NUM = [0-9]+
%%
<YYINITIAL> "+"	      {return new Token (sym.PLUS,        yychar,yychar+1,yytext(),yyline);}
<YYINITIAL>{NUM}      {return new Token (sym.NUM,         yychar,yychar+yytext().length(),new Integer(yytext()),yyline);}
<YYINITIAL>{WHITESPACE}   { }
. { throw new Exception ("Lexical: unmatched input at line " + (yyline+1));
  }