How to enable disabled movement keys in netrw?

Question

Recently I started using and learning Vim. I turned off movement keys in my .vimrc file like this:

noremap <Up> <NOP>
noremap <Down> <NOP>
noremap <Left> <NOP>
noremap <Right> <NOP>
noremap h <NOP>
noremap j <NOP>
noremap k <NOP>
noremap l <NOP>

However, I'd like to use netrw file browser, but I can't navigate in it without movement keys (h, j, k, and l, or arrow keys), since I disabled them. Is there a way to allow movement keys in netrw (basically, allow movement only when a cursor in it)?

Answer 1

My real answer is "don't do that", but if you insist, you could do something like:

noremap <expr> h &filetype ==? 'netrw' ? 'h' : ''
noremap <expr> j &filetype ==? 'netrw' ? 'j' : ''
noremap <expr> k &filetype ==? 'netrw' ? 'k' : ''
noremap <expr> l &filetype ==? 'netrw' ? 'l' : ''

These commands create mappings that check the filetype, and then either perform an hjkl movement or do nothing, accordingly.

See :help :map-expression for details on how this works.

Answer 2

Since you said you're learning vim, I'd point you to learn your way through autocmd. Take a look at this.

I myself am pretty beginner at vimming, so if the solution doesn't work don't think you couldn't pull it off, it's probably because my solution is wrong. But try this anyway.

Put these lines in your .vimrc :

augroup FiletypeSpecificMappings
    autocmd FileType netrw noremap <buffer> j j
    autocmd FileType netrw noremap <buffer> k k
    autocmd FileType netrw noremap <buffer> h h
    autocmd FileType netrw noremap <buffer> l l
augroup END

Here if netrw is opened its local buffer will have the above key mappings, not any other buffers. I searched for ways to compress these four lines into one but couldn't find any.