Complementree.nvim: a tree-sitter powered completion framework

A tree-sitter powered completion framework built for Neovim, configured with functions.

Features and design goals:

• Synchronous
• Configured using functions
• Syntax-aware completion
• No autocompletion

Installation

use {'vigoux/complementree.nvim', requires = {'L3MON4D3/LuaSnip', 'nvim-treesitter/nvim-treesitter'} }

Setting up

complementree.nvim works using functions that are called based on the syntax tree of the file. An example configuration is the following:

local comp = require"complementree"
local s = require"complementree.defaults"

local lsp_completion = {
  default = s.lsp,
  string = s.ins_completion "C-F",
  comment = s.dummy
}

comp.setup {
  default = s.ins_completion "C-N",
  vim = s.ins_completion "C-V",
  c = lsp_completion,
  lua = lsp_completion,
  rust = lsp_completion
}

We define a set of sources that are triggered when calling the complementree.complete() function.

The defaults are:

• treesitter: all names defined in the current file (very basic for now)
• lsp: lsp-only source, with LSP snippets enabled
• luasnip: luasnip snippets
• ctags: tagfile elements, a more configurable form of <C-X><C-]>
• filepath: paths under the current directory
• dummy: nothing
• ins_completion: trigger a <C-X><C-*> completion

After calling the setup function, you can trigger completion by calling complementree.complete().

Combining sources

You can combine the matches of sources using things called combinators.

There is a few combinators already existing, that take a matches function as input:

• combine: just concatenates the results of multiple matches functions, returns a matches function
• chain: mimics mucomplete chaining, returns the first non-empty matches of the provided functions
• non_empty_prefix: checks that the prefix is non-empty before triggering completion
• optional: takes two matches functions, and triggers the second one only if the first one returns at least one result
• wrap: triggers the completion using this matches function.

The currently implemented matches functions are:

• lsp_matches: for lsp-only matches
• luasnip_matches: for LuaSnip matches.
• filepath_matches: for files under the current directory
• ctags_matches: for matches in the current tagfile
• treesitter_matches: for symbols defined in the current file (basic for now)

All the _matches function take a table of options as parameters, dig into the sources file for more info about that.

Using combinators, you can complete using LSP + LuaSnip with the following:

local s = require"complementree.sources"
local cc = require"complementree.combinators"

lsp_and_luasnip = cc.combine(s.luasnip_matches {}, s.lsp_matches {})

Filtering and sorting results

There are two special types of combinators: filters and comparators.

They simply change the order and filter the completion results, and there are quite a bunch of them.

Filters

• prefix: only keep suggestions that start with the current written word
• strict_prefix: same as prefix but be a strict prefix (different than written word)
• amount(n): only take the first n suggestions

Comparators

• alphabetic: sort results alphabetically
• length: sort results by length If you have romgrk/fzy-lua-native installed, there will also be:
• fzy: sort based on the fuzzy score (case sensitive)
• ifzy: case insensitive version

Query-based completion filters

In your setup calls, for a specific filetype completion, you can specify your completion filters based on queries. What this will do is use the query to determine whether the provided completion method should be triggered. For example, those are equivalent:

-- This
{
  comment = defaults.lsp
}

-- Is equivalent to that
{
  ["(comment) @c"] = defaults.lsp
}

-- And that
{
  ["(comment) @c"] = { c = defaults.lsp }
}

As a key, you can specify a table, and in this case, depending on what capture of the query the current cursor position matches, you will trigger the corresponding completion method.

Utilities

A threading-macro-like function in also provided for convenience, which looks line combinators.pipeline(source, ...) and just applies all combinators in the ... one by one.

Examples

Fuzzy LSP:

combinators.pipeline(sources.lsp_matches {}, comparators.fzy, filters.amount(6))

Fuzzy LSP and LuaSnip only if LSP returns something:

combinators.pipeline(combinators.optional(source.lsp_matches {}, source.luasnip_matches {}), comparators.fzy, filters.amount(6))

Look in the defaults file for more.