Completion source for nvim-cmp using R.nvim as backend.

Use a plugin manager such as vim-plug or packer.

Register the source for nvim-cmp:

require'cmp'.setup {
  sources = {
    { name = 'cmp_r' },
  }
}

cmp-r has the following options:

• filetypes: The list of file types for which the source should be enabled. Default: {'r', 'rmd', 'quarto', 'rnoweb', 'rhelp'}

• doc_width: The expected maximum width of the floating documentation window. Valid values are between 30 and 160. Default: 58.

  See also the option maxwidth in lspkind.nvim.

• trigger_characters: List of characters to trigger completion. Default: { " ", ":", "(", '"', "@", "$" }.

• fun_data_1: List of functions that receive a data.frame as its first argument and for which the data.frames columns names should be completed. This option is overridden by g:R_fun_data_1. Default: {'select', 'rename', 'mutate', 'filter'}.

• fun_data_2: Dictionary with parent functions as keys. The value of each key is a list of functions that are expected to be nested in the parent function which receives a data.frame as its first arguments. Column names of the data.frame are completed as arguments of the nested function. This option is overridden by g:R_fun_data_1. Default: {ggplot = {'aes'}, with = {'*'}}.

• quarto_intel: Path to yaml-intelligence-resources.json which is part of quarto application and has all necessary information for completion of valid YAML options in an Quarto document. Default: nil (cmp-r will try to find the file).

Below is an example of how to set theses options:

require("cmp_r").setup({
  filetypes = {"r", "rmd", "quarto"},
  doc_width = 58,
  quarto_intel = "~/Downloads/quarto-1.1.251/share/editor/tools/yaml/yaml-intelligence-resources.json"
  })

Note: The algorithm for finding the first argument of the parent function is very simple and would wrongly recognize data as the name of the data.frame in the following code:

ggplot(data = my_data_frame, mapping = aes(

The source cmp_r does not require any special configuration of nvim-cmp to work, and people have different preferences and workflows. Anyway, I share below what worked best for me:

• cmp-r sets the field sortText of completed items as "0" for function arguments and "9" for everything else. This means that function arguments will always be at the top of the list of suggestions if you put cmp.config.compare.sort_text at the top of list of compare nvim-cmp functions.

• Install a Nerd font and install and configure your terminal emulator to use it. Then install lspkind.nvim to have symbols representing the kind of object whose name is being completed.

• The names of kind of objects are generic names of the LSP server protocol and do not match the classes of R objects. So, it is better to hide the names and display only the symbols.

An example following the above suggestions:

cmp.setup({
    formatting = {
        fields = {'abbr', 'kind', 'menu'},
        format = lspkind.cmp_format({
            mode = 'symbol', -- show only symbol annotations
            maxwidth = 50, -- prevent the popup from showing more than provided characters
            ellipsis_char = '...', -- the truncated part when popup menu exceed maxwidth
            before = function(entry, item)
                local menu_icon = {
                    nvim_lsp = '',
                    vsnip = '',
                    path = '',
                    cmp_zotcite = 'z',
                    cmp_r = 'R'
                }
                item.menu = menu_icon[entry.source.name]
                return item
            end,
        })
    },
    sources = cmp.config.sources({
        { name = 'vsnip' },
        { name = 'cmp_zotcite' },
        { name = 'cmp_r' },
        { name = 'nvim_lsp' },
        { name = 'path', option = { trailing_slash = true } },
    }),
})

Since cmp-r and the R package languageserver provide completions for the same code, and completions from the languageserver might be the first ones to be displayed by nvim-cmp, you may want to put this in your ~/.Rprofile:

# Disable completion from the language server
options(languageserver.server_capabilities =
        list(completionProvider = FALSE, completionItemResolve = FALSE))