I'm interested in a more general approach to extend Boost.ProgramOptions with new parsers. Then you could add a CGI query parser while I could add a parser which reads configuration data from JSON files. Then however Boost.ProgramOptions would need to support something more sophisticated than key=value pairs. I'm not sure if this can be easily generalized?
Maybe an extension facility for ProgramOptions parsers could be made. I don't know yet exactly how this part of the library is designed and how easy it is to extend it. My approach would thus be to implement what I've proposed by first merely making another whole parser. Then I'll have a better sight and I can decide if we can go further towards genericity and extension features. However, the extension possibilities of the library are already at a good level due to its separation into 3 parts: descriptions, parsing and storage. not sure if the parsing parts really has to be even more generic... As long as JSON has a hierarchical structure, wouldn't it be better for you to use the future property_tree library? Bruno