anchor.diff:  
   number
       : integer
  -//    | FLOAT_NUMBER
  +    | FLOAT_NUMBER
       ;
   
   integer
       : DECIMAL_INTEGER
       | HEX_INTEGER
  +    ;
  +
  +FLOAT_NUMBER
  +    : POINT_FLOAT
  +    | EXPONENT_FLOAT
       ;
   
   string
  
positive.code: MINUS  : '-';
  DIV    : '/';
  MOD    : '%';
  
  LESS_THAN    : '<';
  GREATER_THAN : '>';
  
negative.code: factor
      : op='+' factor    # unaryExpr
      | op='-' factor    # unaryExpr
      | '(' test ')'     # parenExpr
      | atom             # atomExpr
      ;
  
  atom
      : NAME
      | funcinvoke
      | number
      | string+
      | NONE
  