anchor.diff:          TOKMATCH
           match_brace
           ( EQUAL | LARROW ) assign_value SEMICOLON
  -
  -    rule module_param:
  -        Type_nitem [ VAR | STAR ]
   
       rule module_declaration:
           TOKMODULE [ LBRACKET assign_value RBRACKET ] typevar_item_or_var
  
positive.code:             TOKENDINTERFACE [ COLON VAR ]
          )
  
      rule match_arg:
          DOT ( term<<[]>> | STAR )
          | match_brace
  
negative.code:     rule dot_field_item:
          [ VAR COLON ] dot_item
  
      rule dot_field_list:
          dot_item
          | NUM
          | VAR
          | LBRACE dot_field_item (COMMA dot_field_item)* RBRACE
  
      rule tagged_dot_list:
          TOKTAGGED VAR
          [
              (dot_field_list
              | LPAREN
                  ( dot_field_list
                  | tagged_dot_list
                  )
                  RPAREN
              )
          ]
  
      rule dot_field_selection:
            tagged_dot_list
          | LPAREN tagged_dot_list RPAREN
          | NUM
  
      # A factor is the product and division of terms
  