import java_cup.runtime.*; // defines the Symbol class

// The generated scanner will return a Symbol for each token that it finds.
// A Symbol contains an Object field named value; that field will be of type
// TokenVal, defined below.
//
// A TokenVal object contains the line number on which the token occurs as
// well as the number of the character on that line that starts the token.
// Some tokens (e.g., literals) also include the value of the token.

class TokenVal {
 // fields
    int linenum;
    int charnum;
 // constructor
    TokenVal(int l, int c) {
        linenum = l;
	charnum = c;
    }
}

class IntLitTokenVal extends TokenVal {
 // new field: the value of the integer literal
    int intVal;
 // constructor
    IntLitTokenVal(int l, int c, int val) {
        super(l,c);
	intVal = val;
    }
}


// The following class is used to keep track of the character number at which
// the current token starts on its line.
class CharNum {
  static int num=1;
}
%%

DIGIT=		[0-9]
WHITESPACE=	[\ \t]

// The next 3 lines are included so that we can use the generated scanner
// with java CUP (the Java parser generator)
%implements java_cup.runtime.Scanner
%function next_token
%type java_cup.runtime.Symbol

// Tell JLex what to do on end-of-file
%eofval{
return new Symbol(sym.EOF);
%eofval}

// Turn on line counting
%line

%%

{DIGIT}+   {// NOTE: the following computation of the integer value does NOT
	    //       check for overflow.  This must be changed.
	    int val = (new Integer(yytext())).intValue();
	    Symbol S = new Symbol(sym.INTLITERAL,
			          new IntLitTokenVal(yyline+1, CharNum.num, val)
				 );
	    CharNum.num += yytext().length();
	    return S;
	   }

\n	   {CharNum.num = 1;}

{WHITESPACE}+  {CharNum.num += yytext().length();}

"+"	   {Symbol S = new Symbol(sym.PLUS, new TokenVal(yyline+1, CharNum.num));
	    CharNum.num++;
	    return S;
	   }
	    
.	   {Errors.fatal(yyline+1, CharNum.num,
			 "ignoring illegal character: " + yytext());
	    CharNum.num++;
	   }