anchor.diff:  directive
       :   '@' NAME ':' valueOrVariable
       |   '@' NAME
  +    |   '@' NAME '(' argument ')'
       ;
   
   typeCondition
  
positive.code: selectionSet
      :   '{' selection (','? selection)* '}'
      ;
  
  
  operationType
      :   'query'
  
negative.code: 
  */
  
  grammar GraphQl;
  
  document
  