Mapping with motion

Question

I'm trying to understand how can I use operator with subsequent motion inside a mapping. For example:

nmap /c c{here we pending for a motion}/<C-r>"<CR>

The map should do the following:

1. Activate c operator and listen for the next motion;
2. Eg, I can type here t, to change everything before the next comma;
3. Go to insert mode deleting everything between cursor and the comma;
4. Deleted text is automatically searched as a pattern

So to put it simple, after motion text is removed, I'm leaved in insert mode with highlighted occurrences of the deleted text. I would be very grateful if somebody help me to puzzle out this case.

UPDATE

The answers are almost what I want. But! When I press /cw, type something instead of the word, then press <Esc>. After I expect to do the same with the next occurrences. But after presing n (go to next occurrence) and . (repeat last command) it just prepend last typed text instead of replacing it. The main goal of the mapping is using it with n/N and . to repeat. Have I missed something?

Answer 1

vim supports operator-mapping :h map-operator.

What you need is an operatorfunc, and a mapping. for your needs, the followings codes work. Well it is just an example, you refine further.

nmap  <silent> /c :set opfunc=SpecialChange<CR>g@
function! SpecialChange(type)
    silent exec 'normal! `[v`]d'    
    silent exec 'let @/=@"' 
    startinsert
endfunction

Note that exec 'let @/=@"' just for highlighting the codes in buffer. If you don't want to see the highlighting immediately, you can just let @/=@"

Answer 2

It is easier to implement (and to document) complex mappings by using functions:

function! DoMagic()
   execute "normal! d".input("enter motion: ")
   let @/=@"
   startinsert
endfunction

Then make your mapping call that function:

nmap /c :call DoMagic()<CR>

---

Edit:

If your intention is to perform search & replace in a large number of places you should try the substitute command: :s. You could change your mapping to copy the visual selection to the search pattern:

function! DoMagic2()
   normal! gv"ay
   return @a
endfunction

vmap /c :<c-w>%s/<C-r>=DoMagic2()<CR>//gc<left><left><left>

Answer 3

This solution works with "repeat last command" (aka .):

nmap <silent> /c :set opfunc=ChangeOccurence<CR>g@

function! ChangeOccurence(type)
  exec 'normal! `[v`]y'
  let @/ = @"
  call feedkeys('cgn', 'n')
endfunction

When repeating, you don't even need to use n, you can just use . to directly fetch and replace the next occurence if you want to go faster.

Optionally, if you like having highlights of the matching words, you can replace 'cgn' by 'n``cgn'.