anchor.diff:   : literal
    | array_literal
    | dictionary_literal
  - | '__FILE__' | '__LINE__' | '__COLUMN__' | '__FUNCTION__'
  + | playground_literal
  + | '#file' | '#line' | '#cloumn' | '#function'
    ;
   
   array_literal			 : '[' array_literal_items? ']'  ;
  
positive.code:  | postfix_expression parenthesized_expression? trailing_closure  # function_call_with_closure_expression
   | postfix_expression '.' 'init'                                  # initializer_expression
   | postfix_expression '.' 'init' '(' argument_names ')'           # initializer_expression_with_args
   | postfix_expression '.' Decimal_literal                     # explicit_member_expression1
   | postfix_expression '.' identifier generic_argument_clause?     # explicit_member_expression2
   | postfix_expression '.' identifier '(' argument_names ')'       # explicit_member_expression3
  // This does't exist in the swift grammar, but this valid swift statement fails without it
  
negative.code: parameter_clause : '(' ')' |  '(' parameter_list ')'  ;
  parameter_list : parameter (',' parameter)*  ;
  parameter
   : external_parameter_name? local_parameter_name type_annotation? default_argument_clause?
   ;
  external_parameter_name : identifier | '_'  ;
  local_parameter_name : identifier | '_'  ;
  