Writing an autocomplete function

Question

I am trying to use the omnicomplete. It is quite simple to use in insert mode, but I'm having a hard time using it from a function. Here is what I have so far:

" Cmd-. to autocomplete tags, especially HTML, see *i_CTRL-X_CTRL-O*
function Autocomplete()
    normal! i</<C-x><C-o>
    " If it was an empty omni-complete, delete those three characters
    let char_three_left = getline('.')[col('.')-3]
    if (char_three_left == '<')
        normal!XXX
    endif
endfunction
inoremap <leader>. <C-O>:call Autocomplete()<CR>\

However, it seems to enter in the text literally, and I am having a hard-time escaping it when in insert mode. What would be the proper way to do this?

---

I suppose maybe I just need to call :call htmlcomplete#CompleteTags(...) but there seems to be little to no documentation on that.

Answer 1

This turned out to be quite tricky, but it's possible to manually trigger the omni-complete call. The important help sections are: omnifunc and primarily complete-functions:

" Cmd-. to autocomplete tags, especially HTML, see *i_CTRL-X_CTRL-O*
function Autocomplete()
    " See :h *complete-functions* for how to use the omni-complete
    " note: the following function is geared towards HTML
    let idx = htmlcomplete#CompleteTags(1, '')
    let completion = htmlcomplete#CompleteTags(0, idx)[0]
    if completion != '>'
        execute ('normal!i' . completion)
    else
        normal! XX
    endif
endfunction
inoremap <leader>.  </<C-O>:call Autocomplete()<CR><Right>
nnoremap <leader>. i</<C-O>:call Autocomplete()<CR><Esc><Right><Right>

Notice also the use of </ before entering the function -- why? I have no idea, but it seems the insert wasn't being done (or at least registering) for the autocomplete function to pick it up.