anchor.diff:  -type packed_encode_fun() ::
        fun( (Value :: any()) -> iolist() ).
   
  +-ifndef(EDOC).
   -spec gen_required_field/3 :: (
       Code :: piqirun_code(),
       GenValue :: encode_fun(),
  
positive.code: -spec string_to_block/2 :: (
      Code :: piqirun_code(),
      X :: string() | binary() ) -> iolist().
  
  
  non_neg_integer_to_varint(Code, X) when X >= 0 ->
  
negative.code: %
  %       -type piqi_float() :: float() | '-infinity' | 'infinity' | 'nan'.
  %
  -ifndef(EDOC).
  -spec parse_ieee754_64/1 :: (<<_:64>>) -> no_return().
  -spec parse_ieee754_32/1 :: (<<_:32>>) -> no_return().
  -endif.
  
  parse_ieee754_64(_) -> throw_error('ieee754_infinities_NaN_not_supported_yet').
  parse_ieee754_32(_) -> throw_error('ieee754_infinities_NaN_not_supported_yet').
  