anchor.diff:      :   INDENT statements DEDENT
       ;
   
  -match
  -    :   MATCH expression match_block
  -    ;
  -
  -match_block
  -    :   INDENT match_options DEDENT
  -    ;
  -
  -match_options
  -    :   PIPE match_option (NL PIPE match_option)* NL*
  -    ;
  -
  -match_option
  -    :   match_expression block
  -    ;
  -
  -match_expression
  -    :   literal
  -    |   match_expression (PIPE match_expression)+
  -    ;
  -
   inline_block
  -    :   ARROW 
  -        (   expression
  -        |   LBRACE statement (SEMI statement)* RBRACE
  -        )
  +    :   LBRACE statement (SEMI statement)* RBRACE
       ;
   
   namespace
  
positive.code: // §3.12 Operators
  
  ARROW           :   '->';
  ELIPSES         :   '..';
  
  ASSIGN          :   '=';
  GT              :   '>';
  
negative.code: fragment
  BinaryDigit
      :   [01]
      ;
  
  // Range Literal
  RangeLiteral
      :   IntegerLiteral '..' IntegerLiteral
      ;
  
  // §3.10.2 Floating-Point Literals
  