_region_peek8
conv = _region_peek8(&rc->rc_table, idx);
if (_region_size(r) == 0 || _region_peek8(r, _region_size(r)-1) != ';')
if (_region_size(r) == 0 || _region_peek8(r, 0) != '=')
if (_region_size(r) == 0 || !_bcs_isdigit(_region_peek8(r, 0)))