Omni completion for items without documentation

[ilaitinen]

Under the hood, rescript-editor-analysis.exe returns null instead of an object/dict when a completion item has no documentation. This results in multiple errors in rescript#Complete.

A minimal example with vim-plug and the latest versions of vim-rescript and rescript (tested in VIM 8.2 and in Neovim 0.6.1):

~/.vimrc or ~/.config/nvim/init.vim:

call plug#begin()
Plug 'rescript-lang/vim-rescript'
call plug#end()

set omnifunc=rescript#Complete
set completeopt+=preview

Example.res:

let myInteger = 1
let myString = "2"

Also needed:

• complete/completion mismatch fix: #56

Make sure the project is built. Type let my as the last line of Example.res and hit <C-x><C-o> in insert mode. You'll get the following errors twice:

Error detected while processing function rescript#Complete:
line   36:
E121: Undefined variable: value
Press ENTER or type command to continue
Error detected while processing function rescript#Complete:
line   38:
E121: Undefined variable: entry
Press ENTER or type command to continue
Error detected while processing function rescript#Complete:
line   38:
E116: Invalid arguments for function add(l:ret, entry)
Press ENTER or type command to continue

After hitting ENTER enough times:

-- Omni completion (^O^N^P) Pattern not found

I think the problem lies here:

https://github.com/rescript-lang/vim-rescript/blob/faeeb2deef1ad0ec67fc892ceeb9949f3bf2d77c/autoload/rescript.vim#L369

item.documentation is null for undocumented matches.

I tried to replace the offending line with the following, and now omni completion works both for built-in items and for undocumented local items (but I'm no expert in vimscript, so this may be a silly way to do it):

    if type(item.documentation) == v:t_dict
      let l:info = item.documentation.value
    else
      let l:info = item.detail " or some default value
    endif

    let entry = { 'word': item.label, 'kind': l:kind, 'info': l:info }