anchor.diff:  
   variable_declaration_head : attributes? declaration_specifiers? 'var'  ;
   variable_name : identifier  ;
  -getter_setter_block : { getter_clause setter_clause?}  | { setter_clause getter_clause }  ;
  -getter_clause : attributes? get code_block  ;
  -setter_clause : attributes? set setter_name? code_block  ;
  +getter_setter_block : '{' getter_clause setter_clause?'}'  | '{' setter_clause getter_clause '}'  ;
  +getter_clause : attributes? 'get' code_block  ;
  +setter_clause : attributes? 'set' setter_name? code_block  ;
   setter_name : ( identifier )  ;
  -getter_setter_keyword_block : { getter_keyword_clause setter_keyword_clause?} | { setter_keyword_clause getter_keyword_clause }  ;
  -getter_keyword_clause : attributes? get  ;
  -setter_keyword_clause : attributes? set  ;
  -willSet_didSet_block : { willSet_clause didSet_clause?} | { didSet_clause willSet_clause }  ;
  -willSet_clause : attributes? willSet setter_name? code_block  ;
  -didSet_clause : attributes? didSet setter_name? code_block  ;
  +getter_setter_keyword_block : '{' getter_keyword_clause setter_keyword_clause?'}' | '{' setter_keyword_clause getter_keyword_clause '}'  ;
  +getter_keyword_clause : attributes? 'get'  ;
  +setter_keyword_clause : attributes? 'set'  ;
  +willSet_didSet_block : '{' willSet_clause didSet_clause?'}' | '{' didSet_clause willSet_clause '}'  ;
  +willSet_clause : attributes? 'willSet' setter_name? code_block  ;
  +didSet_clause : attributes? 'didSet' setter_name? code_block  ;
   
   // GRAMMAR OF A TYPE ALIAS DECLARATION
   
  
positive.code:  | Hexadecimal_literal Hexadecimal_fraction? Hexadecimal_exponent
   ;
  fragment Decimal_fraction : '.' Decimal_literal  ;
  fragment Decimal_exponent : floating_point_e sign? Decimal_literal  ;
  fragment Hexadecimal_fraction : '.' Hexadecimal_literal? ;
  fragment Hexadecimal_exponent : floating_point_p sign? Hexadecimal_literal  ;
  fragment Floating_point_e : [eE] ;
  fragment Floating_point_p : [pP] ;
  fragment Sign : [+-] ;
  
  // GRAMMAR OF A STRING LITERAL
  
  String_literal : '"' Quoted_text '"' ;
  Quoted_text : Quoted_text_item Quoted_text? ;
  Quoted_text_item : Escaped_character | '\\(' expression ')' | ~["\\\u000A\u000D] ;
  Escaped_character : '\\' [0\\tnr"']
   | '\\x' Hexadecimal_digit Hexadecimal_digit
   | '\\u' Hexadecimal_digit Hexadecimal_digit Hexadecimal_digit Hexadecimal_digit
  
negative.code:  | control_transfer_statement ';'?
   ;
  
  statements : statement+ ;
  
  // GRAMMAR OF A LOOP STATEMENT
  
  