Use text variable in library path

I created text variable in project settings. How to use it in library path? I tried to use it like this: ${variable}\library_a.pretty, but it didn’t worked.

File paths aren’t identical to project variables. Paths are found under Preferences menu in their own dialog.

Is there any way to configure path that is specific only for current project?

Good question, but do you really need it? ${KIPRJMOD} means the current project folder, and you can add relative path to that, even “backwards” using double dots.

Maybe, but I need to be able to switch between two directories with libraries: global and local (in project). Global and local libraries have same names.