anchor.diff:      ;
   
   BlockComment
  -    : '/*' .*? '*/' -> skip
  +    : '#' .*? '#' -> skip
       ;
   
   LineComment
  
positive.code:     : expression
      ;
      
  namedConstant
      : Identifier
      ;
      
  updateList 
      : expression Equal expression COMMA updateList
      | expression Equal expression
      ;
  
  bitwiseExpr 
  
negative.code:     
  expression
      : varName                                                                               #VariableName
      | varName Colon expression                                                              #NamedAbbreviation
      | LeftParen widthOrSizeExpr number RightParen                                           #SizeQuery
      | LeftParen arithmeticExpr widthOrSizeExpr leftExpr rightExpr RightParen                #ArithExpr
      | LeftParen notExpr LeftBracket widthOrSizeExpr RightBracket expression RightParen      #NotExprWidth
      | LeftParen bitwiseExpr widthOrSizeExpr leftExpr rightExpr RightParen                   #BitwExprWidth
      | LeftParen comparisonExpr (widthOrSizeExpr)? leftExpr rightExpr RightParen             #CompExprWidth
      | LeftParen concatExpr (widthOrSizeExpr)? leftExpr rightExpr RightParen                 #ConcatExprWidth
      | LeftParen arrExtractExpr widthOrSizeExpr number expression RightParen                 #ArrExtractExprWidth
      | LeftParen bitExtractExpr widthOrSizeExpr expression RightParen                        #BitExtractExprWidth
      | LeftParen genericBitRead widthOrSizeExpr expression (version)? RightParen             #ReadExpresssionVersioned
      | LeftParen selectExpr widthOrSizeExpr leftExpr rightExpr expression RightParen         #SelectExprWidth
      | LeftParen exprNegation (widthOrSizeExpr)? expression RightParen                       #NegationExprWidth
      | version                                                                               #VersionExpr
      | number                                                                                #Singleton
      ;
  