How can I call functions inside the mapping function silently?

[smjonas]

I am working on cmp-nvim-ultisnips and we had a few requests about calling functions silently.

Currently we have this mapping in the readme:

local t = function(key)
  vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes(key, true, true, true), "n", true)
end

mapping = {
  ["<Tab>"] = cmp.mapping(function(fallback)
    if cmp.get_selected_entry() == nil and vim.fn["UltiSnips#CanExpandSnippet"]() == 1 then
      t("<C-r>=[UltiSnips#CursorMoved(), UltiSnips#ExpandSnippet()][1]<cr>")
    elseif vim.fn["UltiSnips#CanJumpForwards"]() == 1 then
      t("<C-r>=[UltiSnips#CursorMoved(), UltiSnips#JumpForwards()][1]<cr>")
    elseif cmp.visible() then
      cmp.select_next_item()
    else
      fallback()
    end
  )
}

However, each time a snippet is expanded the text =[UltiSnips#CursorMoved(), UltiSnips#ExpandSnippet()][1] is printed to the command line. cmp calls the function
itself silently but I don't know how to change such that the function itself is called
silently.

I know this is not directly related to cmp but I thought maybe someone here has an idea how to
achieve this.

[hrsh7th]

The feedkeys isn't support silent. So this problem is a bit complex to solve.

1. You should define mapping.

inoremap <silent> <Plug>(my-ultisnips-expand) <C-r>=[UltiSnips#CursorMoved(), UltiSnips#ExpandSnippet()][1]<CR>

2. Then you can feed plug map.

local t = function(keys, mode)
  vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes(keys, true, true, true), mode or 'n', true)
end

...

  ["<Tab>"] = cmp.mapping(function(fallback)
    if cmp.get_selected_entry() == nil and vim.fn["UltiSnips#CanExpandSnippet"]() == 1 then
      t('<Plug>(my-ultisnips-expand)', '')
    elseif vim.fn["UltiSnips#CanJumpForwards"]() == 1 then
      ...
    end
  )

[smjonas]

I think the problem is that cmp sets noremap = true so the <Plug> mapping is not evaluated recursively. Could this be the reason?

[hrsh7th]

No. You are doing the manual feedkeys so nvim-cmp's implementation does not related to this.
Could you paste your code?

[smjonas]

This is the minimal cmp config:

local cmp = require("cmp")

cmp.setup {
  snippet = {
    expand = function(args)
     vim.fn["UltiSnips#Anon"](args.body)
    end,
  },
  sources = {
    { name = "ultisnips" },
  },
  mapping = {
    ["<Tab>"] = cmp.mapping(function(fallback)
      require("cmp_nvim_ultisnips.mappings").expand_or_jump_forwards(fallback)
    end, { "i", "s" }),
  },
}

"cmp_nvim_ultisnips.mappings" module:

local M = {}

local t = function(keys, mode)
  vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes(keys, true, true, true), mode or 'n', true)
end

function M.expand_or_jump_forwards(fallback)
    vim.cmd[[
imap <silent> <Plug>(cmpu-expand)
\ <C-r>=[UltiSnips#CursorMoved(), UltiSnips#ExpandSnippet()][1]<cr>

imap <silent> <Plug>(cmpu-jump-forwards)
\ <C-r>=[UltiSnips#CursorMoved(), UltiSnips#JumpForwards()][1]<cr>

imap <silent> <Plug>(cmpu-jump-backwards)
\ <C-r>=[UltiSnips#CursorMoved(), UltiSnips#JumpBackwards()][1]<cr>
  ]]

  if cmp.get_selected_entry() == nil and vim.fn["UltiSnips#CanExpandSnippet"]() == 1 then
    t('<Plug>cmpu-expand', '')
  elseif vim.fn["UltiSnips#CanJumpForwards"]() == 1 then
    t('<Plug>cmpu-jump-forwards', '')
  elseif cmp.visible() then
    cmp.select_next_item()
  else
    fallback()
  end
end

return M

Which can also be seen here:

Edit: changing imap to inoremap does not help
Edit 2: I changed function to local t = function...

[hrsh7th]

t('<Plug>cmpu-expand', '') should be t('<Plug>(cmpu-expand)', '')...

[smjonas]

Oh my 😆... Thank you it works now! Didn't know this was necessary