anchor.diff:          | TOKACTION
           | TOKACTIONVALUE
   
  -    rule Type_nitem:
  -        Type_item
  -        | VAR [ LBRACKET NUM (COLON NUM)* RBRACKET ]
  -        | CLASSVAR typevar_item_or_var
  -
       rule Type_list:
           ( Type_nitem
           | LPAREN Type_nitem (COMMA Type_nitem)* RPAREN
           )
   
  -    rule enum_element: term<<[]>> [EQUAL expr<<[]>>]
  +    rule enum_element:
  +        term<<[]>> [EQUAL expr<<[]>>]
   
       rule deriving_type_class:
           TOKEQ | TOKBITS | TOKBOUNDED
  
positive.code:           tagged_dot_list
          | LPAREN tagged_dot_list RPAREN
          | NUM
  
      # A factor is the product and division of terms
      rule factor<<V>>: nterm<<V>>           {{ v = nterm }}
  
negative.code:         SEMICOLON
  
      rule module_item:
            import_declaration
          | interface_declaration
          | method_declaration
          | typedef_declaration
  
      rule package_declaration_item:
            module_item
          | export_declaration
          | function_declaration
          | module_declaration
          | instance_declaration
          | let_statement
          | rule_statement
          | typeclass_declaration
  