options { UNICODE_INPUT = true; }

PARSER_BEGIN(chaincalc)

package javaKurs2.javacc;

public class chaincalc {

  public static void main(String args[]) 
  throws ParseException {

    chaincalc parser = new chaincalc(System.in);
    parser.Input();
  }
}

PARSER_END(chaincalc)

// Lexer definition

SKIP : { " " | "\r" | "\t" }

TOKEN :
{  <LF: "\n">
|  <MINUS: "-">
|  <PLUS: "+">
| < NUM: (<DIGIT>)+ ( "." (<DIGIT>)+ )? >
| < DIGIT : ["0"-"9"] >
}

// <EOF> is predefined token for "end of file"

void Input() :
{ 
  double result = 0.0; //important: initialize because optional on RHS
}
{
  ([result=Expr()] <LF> { System.out.println("result: "+result); } )+
  | <EOF>               { System.exit(-1); }
}

double Expr() :
{ 
  Token tnumber;
  Token tnum = null; // important: initialize because optional on RHS
  double result;
}
{
  tnumber = <NUM> { result = Double.parseDouble(tnumber.image); }
  ( (<PLUS> tnum=<NUM>) { result+=Double.parseDouble(tnum.image); } |
   (<MINUS> tnum=<NUM>) { result-=Double.parseDouble(tnum.image); })* 
  { return result; 
  }
}