automation - Vim function to update class definition to reflect current location

Question

I'm trying to take my vimscript to the next level. As a follow up to my other question about generating a class definition from a file path, how would you implement the following in vimscript?

Given I have a file at lib/foo/bar/buz.rb that looks like this:

module Foo
module Bar

   class Buz
     ...
   end

end
end

If I move the file to lib/cat/dog/cow/buz.rb, can I create a function to quickly update the file to look like this?

module Cat
module Dog
module Cow

  class Buz
    ...
  end

end
end
end

Answer 1

You can use expand('%:p:h:t') to get the current file's directory. Add additional :h modifiers to get parent directories. See :help filename-modifiers.

substitute('foo', '^.', 'u&', '') will upper-case the first letter.

To do the replacement in the buffer, a :substitute, probably with a :help sub-replace-expression will do.