Add function for getting a types fully qualified name

[jacobperron]

As opposed the type name 'foo::msg::Bar', the new function let's us get the ROS namespaced name 'foo/msg/Bar'.

This seems generally useful, and would simplify logic in ros2/rviz#591 for example.

I'm open to changing the name of the new function if there are better suggestions.

[wjwwood]

Makes sense to me, but should we also have just name? It just seems odd to "reserve" that term by using "fully qualified name" if we're not gonna have it. And if we intend to have it, now would be a good time to add it I guess.

[jacobperron]

Good suggestion. What do you think about adding three new functions instead?

• name() (e.g. returns Bar)
• namespace() (e.g. returns foo/msg)
• name_with_namespace() (e.g. returns foo/msg/Bar)

[wjwwood]

I like fully_qualified_name, and name seems ok, but we can't do just namespace I think due to keyword collisions. Maybe msg_namespace or namespace_ or we could prefix all with type, e.g. type_name, type_namespace, and type_fully_qualified name/fully_qualified_type_name.

The other option is just to have name return the full name and let users split it themselves.

I don't have a strong opinion one way or the other.

[jacobperron]

The other option is just to have name return the full name and let users split it themselves.

I like this option. I think it's unlikely a user only wants the last part of the name (or just the namespace), and in this case they can do the splitting themselves.

[jacobperron]

@wjwwood I've renamed the function to name(), see 0e79466.

[jacobperron]

Testing rosidl_generator_cpp, rosidl_runtime_cpp, and test_msgs:

• Linux
• Linux-aarch64
• macOS
• Windows