How can I bind coc function from within my own function (used for insert mode)

[reteehee]

How can I call a coc function like coc#refresh() or coc#_select_confirm() from within my own function (which used for insert mode):

For example I have this:

" Use <tab> to trigger completion
fun! s:coc_comp_tab() abort
    if pumvisible()
        return "\<c-n>"
    " If the next char is closed pairs, jump
    elseif getline('.')[col('.') - 1] =~ "['\"`)\\]}>]"
        return "\<right>"
    " If the previous char is space, tab
    elseif getline('.')[col('.') - 2] =~# '\s'
        return "\<tab>"
    else
        " Fucking try and error
        coc#refresh()
        " call coc#refresh()
        " return "\<c-o>:call coc#refresh()\<cr>"
    endif
endfun

inore <silent><expr> <tab> <sid>coc_comp_tab()

Please see the else clause above, that must be an error or throw unexpected result (in my case, it typed 0 when there's no popup completion window).

I want it to behave like the official example, when there's no condition meets, just do coc#refresh():

inoremap <silent><expr> <TAB>
      \ pumvisible() ? "\<C-n>" :
      \ <SID>check_back_space() ? "\<TAB>" :
      \ coc#refresh()

[chemzqm]

function! coc#refresh() abort
  return "\<c-r>=coc#start()\<CR>"
endfunction

You should return the expression the same as coc#refresh()

[reteehee]

Where's coc#start() come from, if its equivalent to coc#refresh(), what about the equivalent for the others like coc#_select_confirm. Seems like there's no documentation.

Also another function that doesn't have documentation like coc#rpc#request()

[chemzqm]

They're supposed to be internal, you can simply use return coc#refresh()