I tried following this tip from vim wikia:
:inoremap \fn <C-R>=expand("%:t:r")<CR>
For me this doesn't make any difference to the functionality of Ctrlr% in insert mode (it still just gives the full path and file extension), so I was looking at that and some linked tips and vim help sections, to no avail.
Why doesn't this work? Should it? If so could there be something in my config or an extension that ruins it?
Somewhat tangentially, what is the
\fn about? I've seen variations on this in other map commands but can't find any explanation of it. If someone could break this line down completely and explain the meaning that would be great.