anchor.diff:     | name 
      | string
      | ('(' expression ')')
  +   | 'not' expression
      ;
   
   dollar
  
positive.code: 
  
  NUMBER
     : '$'? ('-' |'+' )? [0-9a-fA-F] + ('H' | 'h')?
     ;
  
  
  
negative.code:    ;
  
  directive
     : argument? assemblerdirective expressionlist?
     ;
  
  assemblerdirective
  