anchor.diff:  
   literal
       :   IntegerLiteral
  +    |   RangeLiteral
       |   FloatingPointLiteral
       |   CharacterLiteral
       |   StringLiteral
       |   BooleanLiteral
  -    |   'null'
  +    |   NullLiteral
       ;
   
   func
       :   '(' params ')'
           (   match_block
  -        |   block
  +        |   flow_block
  +        |   ARROW (expression | inline_block)
           )
       ;
   
   call
  -    :   Identifier '(' params ')'
  +    :   (   Identifier
  +        |   '(' func ')'
  +        ) '(' params ')'
       ;
   
   params
  
positive.code:     :   BOF statements EOF
      ;
  
  block
      :   flow_block
      |   inline_block
  
negative.code: WITH    :   'with';
  WHILE   :   'while';
  
  // §3.10.1 Integer Literals
  
  IntegerLiteral
  