Changing how the jump section `[` and `]` command works

Question

:help section states:

The "]" and "[" commands stop at the '{' or '}' in the first column. This is useful to find the start or end of a function in a C program.

Is it possible to change the [ and ] commands to jump to a different character or pattern. For example in Markdown, I would like sections defined as titles, lines beginning with # aka the pattern ^#. Similarly in Haskell, I would like it to jump to the next/previous type definition (line containing ::). Both would be set in their respective ftplugin files.

I have tried using map ]] /^#<CR>w but this does not seem to work as expected and leaves text highlighted. It seems like there would be a better way to achieve this.

Is this possible and if so, how would I achieve this?

Answer 1

I stole and renamed the function below from $VIMRUNTIME/ftplugin/python.vim :

function! CustomJump(motion) range
    let cnt = v:count1
    let save = @/
    mark '
    while cnt > 0
        silent! execute a:motion
        let cnt = cnt - 1
    endwhile
    call histdel('/', -1)
    let @/ = save
endfunction

and I use it like this in after/ftplugin/javascript.vim to jump from function definition to function definition:

nnoremap <buffer> ]] :call CustomJump('/function')<cr>
nnoremap <buffer> [[ :call CustomJump('?function')<cr>

You could use it like this for markdown:

nnoremap <buffer> ]] :call CustomJump('/^#')<cr>
nnoremap <buffer> [[ :call CustomJump('?^#')<cr>

or like that for haskell:

nnoremap <buffer> ]] :call CustomJump('/::')<cr>
nnoremap <buffer> [[ :call CustomJump('?::')<cr>

---

But don't forget the awesome :global command:

:g/func/#
:g/^#/#
:g/::/#

Answer 2

The vim-markdown plugin has a function for this in Markdown files:

function! s:JumpToHeader(forward, visual)
  let pattern = '\v^#{1,6}.*$|^.+\n%(\-+|\=+)$'
  if a:visual
    normal! gv
  endif
  if a:forward
    let direction = '/'
  else
    let direction = '?'
  endif
  execute 'silent normal! ' . direction . pattern . "\n"
endfunction

It matches both ATX and setext headers (# foo as well as foo with --- below it). The function is mapped by default to [[ and ]] by the plugin. However, it could benefit from a call to histdel() (as seen in romainl's answer).