Passing a dictionary to a function in viml

Question

I'm building a custom unite.vim source one of the choices should be able to call a function that can accept a dictonary

function! s:source.gather_candidates(args, context) abort "{{{
  let l:nodeInfo = a:context.file
  return [
        \{
        \ 'word': 'delete the current node',
        \ 'kind': 'command',
        \ 'source': s:source.name,
        \ 'action__command': 'call DeleteNode(' . l:nodeInfo .')',
        \ }]
endfunction "}}}

And then to just test it out, echo the dictionary

function! DeleteNode(node) abort "{{{
  let l:currentNode = a:node
  echo l:currentNode
endfunction "}}}

But when I attempt to load my source, I get

Vim(return):E731: using Dictionary as a String

How can I pass the dictionary (around 24 keys) to the function?

@at whoever voted for "off-topic reason": this question is perfectly on-topic as it's a VimL programming question. — Luc Hermitte, Jan 03 '17 at 07:15
Are you absolutely sure you are using `:echo` and not `:echom`? — romainl, Jan 03 '17 at 09:08
When there is an error like this, Vim usually prints out the context. Which line is Vim referring to? — Luc Hermitte, Jan 03 '17 at 09:20
100% sure I was not using `:echom` as I write `echomsg` just to make sure I dont slip up/ — mhartington, Jan 03 '17 at 13:58

Luc Hermitte · Accepted Answer · 2017-01-03T09:28:23.167

2

EDIT: As romainl pointed out, you should be able to use :echo with a dictionary, unlike :echomessage. In that later case, you'll have needed to stringify your dictionary with string() function.

Thus I suspect a similar problem with the building of the action command. I'm not sure about the type of this nodeInfo data, but I suspect a dictionary. In case this is indeed a dictionary, you'll have to build the action__command dictionary entry with: 'call DeleteNode(' . string(nodeInfo) .')', or you could also use the new Partials (:h Partial, IIRC) if your version of Vim is recent enough (7.4.1558+), and if the code that executes this entry also supports funcrefs. They'll be much simpler to use, but definitively not portable to Vim 7.3 nor to vim 7.4.9xx...

edited Jan 03 '17 at 09:28

answered Jan 03 '17 at 07:14

Luc Hermitte

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`:echo` takes strings, numbers, dictionaries, and lists. It's `:echom` that is restricted to strings and throws `E730/E731`. – romainl Jan 03 '17 at 09:06
Going to make this as correct, but not sure what ended up being the issue. When I tried to pass the whole dict, errors would show. But I ended up just modifying the code to only pass the two keys I really needed. A bit messy, but it works and gives me what I need. Thanks! – mhartington Jan 03 '17 at 13:59

Passing a dictionary to a function in viml

1 Answers1