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:         ( EQUAL | LARROW ) assign_value SEMICOLON
  
      rule single_statement:
          let_statement
          | for_statement
          | case_statement
          | if_statement
          | group_statement
          | seq_statement
          | par_statement
          | action_statement
          | match_statement
          | return_statement
          | rule_statement
          | actionvalue_statement
          | while_statement
          | function_declaration
          | variable_declaration_or_call
  
      rule statement_list:
  
negative.code:         [ typevar_param_list ]
          [ provisos_clause ] SEMICOLON
          [
              ( module_item | single_statement)+
              TOKENDMODULE [ COLON VAR]
          ]
  
  