anchor.diff:      | hexcolor
       | ifExpression
       | functionCall
  -    | plusMinus? Lparen ws expression Rparen ws
  +    | plusMinus? Lparen ws expression? Rparen ws
  +    | prio
       ;
   
   ifExpression
  
positive.code:     ;
  
  pseudo
      : Colon Colon? ( identifier | functionalPseudo )
      ;
  
  functionalPseudo
  
negative.code:     ;
  
  className
      : Dot ( Minus | identifier | interpolation )+
      ;
  
  interpolation
  