Replace fqon_t with more advanced identifier type

[heinezen]

Current object, member or namespace IDs are simple std::string types, e.g. fqon_t or fqnn_t. These are sufficient for addressing nyan objects, but are not suitable for advanced operations like:

• Rebuilding the directory/file path of an object (e.g. for fetching relative file referenced by the file type)
• Getting the namespace an object is in
• Checking if an object is nested
• Checking if a member ID is prefixed (with inheritance info)

Ideally, we want something that captures all of these features while still being as easy to use as std::string.

A good start would be to have a class that manages the individual parts of an fqon:

struct fqon_t {
  std::vector<std::string> dir_parts;
  std::string file_part;
  std::vector<std::string> obj_parts;
};

[heinezen]

Using nyan::Namespace for that purpose is probably the best idea, since it already has a similar purpose.

[TheJJ]

the current types are very simple but efficient, and this is a tradeoff between just-read operations and modifications/updates. currently the code is optimized for the former :) so if we change this, we have to consider the benefits well.

[heinezen]

@TheJJ My current idea is to extend nyan::Namespace with the individual fqon parts idea from above (fqons are already split there, but not by directory/file/object) plus some additional helper methods and save the namespace for each object in ObjectInfo. Everything else will still use fqon_t internally. This would solve most of the requirements for object types (not for members and namespaces though).

Getting the directory/file paths for objects is the most important issue right now because it is pretty much required for using file member values with relative paths.

[heinezen]

see a88045a for the current implementation