open config file

[Diederick C. Niehorster <dcnieho@…>]

It would be nice if it is possible to call parse_config_file(const std::basic_string<charT>&, const options_description&, bool allow_unregistered = false); also, next to parse_config_file(std::basic_istream<charT>&, const options_description&, bool allow_unregistered = false); where parse_config_file would take care of opening the file. This would allow for less boiler-plate on part of the user and optimizes the interface for parsign the config file.

[Diederick C. Niehorster <dcnieho@…>]

Sorry, that needed some formatting:

It would be nice if it is possible to call

parse_config_file(const std::basic_string<charT>&, const options_description&, bool allow_unregistered = false);

also, next to

parse_config_file(std::basic_istream<charT>&, const options_description&, bool allow_unregistered = false);

where parse_config_file would take care of opening the file. This would allow for less boiler-plate on part of the user and optimizes the interface for parsign the config file.

[s.ochsenknecht@…]

I see one problem here. How to determine if a ifstream or a wifstream should be used? Both take (const char*) as type for the file name.

One Solution could be: We can implement a template with a basic_string<char> and basic_string<wchar_t> instantiation for the file name. So, if the file name comes with a basic_string<wchar_t> then we use wifstream, the file name has to be converted to (const char* ).

template<charT>
parse_config_file(const std::basic_string<charT>&, ...);

Another solution could be: The function takes const char* parameter for file name which is directly passed to ifstream/wifstream:

template<charT>
parse_config_file(const char*, ...);

But how the user can choose now between ifstream and wifstream?

[Sascha Ochsenknecht]

Implemented option (2). The template parameter is mandatory (char or wchar_t). Default template parameter are not allowed for functions.

Cheers, SAscha

[Sascha Ochsenknecht]

(In [58248]) Allow passing file name to parse_config_file(), Fixes #3264