<CR> binding for autocompletion in Lua

[tomkoid]

Recently I rewrote my NeoVim config to Lua and after recent update the autocompletion didn't work. I figured out, that I need to manually bind the key with some Vim Script code. It worked, but for me it doesn't make sense to have the entire config written in Lua except for this and I don't understand Vim Script that much. How can I write this in Lua?

function! s:check_back_space() abort
  let col = col(".") - 1
  return !col || getline(".")[col - 1] =~ "\s"
endfunction

if has('nvim')
  inoremap <silent><expr> <c-space> coc#refresh()
else
  inoremap <silent><expr> <c-@> coc#refresh()
endif

inoremap <expr> <cr> coc#pum#visible() ? coc#_select_confirm() : "\<CR>"

[chemzqm]

Checkout nvim's doc :h vim.keymap.set()