anchor.diff:   : literal
    | array_literal
    | dictionary_literal
  - | '__FILE__' | '__LINE__' | '__COLUMN__' | '__FUNCTION__'
  + | playground_literal
  + | '#file' | '#line' | '#cloumn' | '#function'
    ;
   
   array_literal			 : '[' array_literal_items? ']'  ;
  
positive.code: parameter_clause : '(' ')' |  '(' parameter_list ')'  ;
  parameter_list : parameter (',' parameter)*  ;
  parameter
   : 'let'?  external_parameter_name? local_parameter_name type_annotation? default_argument_clause?
   | 'var'   external_parameter_name? local_parameter_name type_annotation? default_argument_clause?
   | 'inout' external_parameter_name? local_parameter_name type_annotation
   |         external_parameter_name? local_parameter_name type_annotation range_operator
   ;
  external_parameter_name : identifier | '_'  ;
  local_parameter_name : identifier | '_'  ;
  
negative.code: // GRAMMAR OF A CLASS DECLARATION
  
  class_declaration
   : attributes? access_level_modifier? 'final'? 'class' class_name
     generic_parameter_clause? type_inheritance_clause? class_body
   | attributes? 'final' access_level_modifier? 'class' class_name
     generic_parameter_clause? type_inheritance_clause? class_body
   ;
  class_name : identifier ;
  