LuaSnip

javadoc.mp4

Features

Tabstops
Text-Transformations using Lua functions
Conditional Expansion
Defining nested Snippets
Filetype-specific Snippets
Choices
Dynamic Snippet creation
Regex-Trigger
Autotriggered Snippets
Fast
Parse LSP-Style Snippets either directly in lua, as a vscode package or a snipmate snippet collection.
Expand LSP-Snippets with nvim-compe (or its' successor, nvim-cmp (requires cmp_luasnip))
Snippet history (jump back into older snippets)
Resolve filetype at the cursor using Treesitter

Drawbacks

Snippets that make use of the entire functionality of this plugin have to be defined in Lua (but 95% of snippets can be written in lsp-syntax).
The LSP-parser does not support Regex-Transformations.

Requirements

Neovim >= 0.5 (extmarks)

Setup

Install

Ie. With vim-plug

Keymaps

in vimscript

" press <Tab> to expand or jump in a snippet. These can also be mapped separately
" via <Plug>luasnip-expand-snippet and <Plug>luasnip-jump-next.
imap <silent><expr> <Tab> luasnip#expand_or_jumpable() ? '<Plug>luasnip-expand-or-jump' : '<Tab>' 
" -1 for jumping backwards.
inoremap <silent> <S-Tab> <cmd>lua require'luasnip'.jump(-1)<Cr>

snoremap <silent> <Tab> <cmd>lua require('luasnip').jump(1)<Cr>
snoremap <silent> <S-Tab> <cmd>lua require('luasnip').jump(-1)<Cr>

" For changing choices in choiceNodes (not strictly necessary for a basic setup).
imap <silent><expr> <C-E> luasnip#choice_active() ? '<Plug>luasnip-next-choice' : '<C-E>'
smap <silent><expr> <C-E> luasnip#choice_active() ? '<Plug>luasnip-next-choice' : '<C-E>'

or in lua (includes supertab-like functionality with nvim-cmp)

local function prequire(...)
local status, lib = pcall(require, ...)
if (status) then return lib end
    return nil
end

local luasnip = prequire('luasnip')
local cmp = prequire("cmp")

local t = function(str)
    return vim.api.nvim_replace_termcodes(str, true, true, true)
end

local check_back_space = function()
    local col = vim.fn.col('.') - 1
    if col == 0 or vim.fn.getline('.'):sub(col, col):match('%s') then
        return true
    else
        return false
    end
end

_G.tab_complete = function()
    if cmp and cmp.visible() then
        cmp.select_next_item()
    elseif luasnip and luasnip.expand_or_jumpable() then
        return t("<Plug>luasnip-expand-or-jump")
    elseif check_back_space() then
        return t "<Tab>"
    else
        cmp.complete()
    end
    return ""
end
_G.s_tab_complete = function()
    if cmp and cmp.visible() then
        cmp.select_prev_item()
    elseif luasnip and luasnip.jumpable(-1) then
        return t("<Plug>luasnip-jump-prev")
    else
        return t "<S-Tab>"
    end
    return ""
end

vim.api.nvim_set_keymap("i", "<Tab>", "v:lua.tab_complete()", {expr = true})
vim.api.nvim_set_keymap("s", "<Tab>", "v:lua.tab_complete()", {expr = true})
vim.api.nvim_set_keymap("i", "<S-Tab>", "v:lua.s_tab_complete()", {expr = true})
vim.api.nvim_set_keymap("s", "<S-Tab>", "v:lua.s_tab_complete()", {expr = true})
vim.api.nvim_set_keymap("i", "<C-E>", "<Plug>luasnip-next-choice", {})
vim.api.nvim_set_keymap("s", "<C-E>", "<Plug>luasnip-next-choice", {})

or in lua with nvim-compe

local function prequire(...)
local status, lib = pcall(require, ...)
if (status) then return lib end
    return nil
end

local luasnip = prequire('luasnip')

local t = function(str)
    return vim.api.nvim_replace_termcodes(str, true, true, true)
end

local check_back_space = function()
    local col = vim.fn.col('.') - 1
    if col == 0 or vim.fn.getline('.'):sub(col, col):match('%s') then
        return true
    else
        return false
    end
end

_G.tab_complete = function()
    if vim.fn.pumvisible() == 1 then
        return t "<C-n>"
    elseif luasnip and luasnip.expand_or_jumpable() then
        return t("<Plug>luasnip-expand-or-jump")
    elseif check_back_space() then
        return t "<Tab>"
    else
        return vim.fn['compe#complete']()
    end
    return ""
end
_G.s_tab_complete = function()
    if vim.fn.pumvisible() == 1 then
        return t "<C-p>"
    elseif luasnip and luasnip.jumpable(-1) then
        return t("<Plug>luasnip-jump-prev")
    else
        return t "<S-Tab>"
    end
    return ""
end

vim.api.nvim_set_keymap("i", "<Tab>", "v:lua.tab_complete()", {expr = true})
vim.api.nvim_set_keymap("s", "<Tab>", "v:lua.tab_complete()", {expr = true})
vim.api.nvim_set_keymap("i", "<S-Tab>", "v:lua.s_tab_complete()", {expr = true})
vim.api.nvim_set_keymap("s", "<S-Tab>", "v:lua.s_tab_complete()", {expr = true})
vim.api.nvim_set_keymap("i", "<C-E>", "<Plug>luasnip-next-choice", {})
vim.api.nvim_set_keymap("s", "<C-E>", "<Plug>luasnip-next-choice", {})

For nvim-cmp, it is also possible to follow the example recommendation from the nvim-cmp wiki.

Add Snippets

Vscode-like: For using snippets from a plugin (eg. rafamadriz/friendly-snippets) install it and add
```
require("luasnip.loaders.from_vscode").load()
```
somewhere in your config.
For more info on the vscode-loader, check the examples or documentation.
Snipmate-like: Very similar to Vscode-packages: install a plugin that provides snippets and call the load-function:
```
require("luasnip.loaders.from_snipmate").load()
```
The snipmate format is very simple, so adding custom snippets only requires a few steps:
- add a directory beside your init.vim (or any other place that is in your runtimepath) named snippets.
- inside that directory, create files named <filetype>.snippet and add snippets for the given filetype in it (for inspiration, check honza/vim-snippets).
```
# comment
snippet <trigger> <description>
<snippet-body>
snippet if C-style if
if ($1)
	$0
```
Again, there are some examples and an entry in the docs
Lua: Add the snippets directly to require("luasnip").snippets.<filetype>. An example for this can be found here.
This can also be done much better (one snippet-file per filetype+command for editing the current filetype) than in the example, see this entry in the wiki

Docs and Examples

I highly recommend looking into (or better yet, :luafileing) Examples/snippets.lua before writing snippets in lua.
Check DOC.md (or :help luasnip) for in-depth explanations of the different nodes. The Wiki contains some pretty useful extensions to Luasnip.

Config

history: If true, Snippets that were exited can still be jumped back into. As Snippets are not removed when their text is deleted, they have to be removed manually via LuasnipUnlinkCurrent if delete_check_events is not enabled (set to eg. 'TextChanged').
updateevents: Choose which events trigger an update of the active nodes' dependents. Default is just 'InsertLeave', 'TextChanged,TextChangedI' would update on every change.
region_check_events: Events on which to leave the current snippet if the cursor is outside its' 'region'. Disabled by default, 'CursorMoved', 'CursorHold' or 'InsertEnter' seem reasonable.
delete_check_events: When to check if the current snippet was deleted, and if so, remove it from the history. Off by default, 'TextChanged' (perhaps 'InsertLeave', to react to changes done in Insert mode) should work just fine (alternatively, this can also be mapped using <Plug>luasnip-delete-check).
store_selection_keys: Mapping for populating TM_SELECTED_TEXT and related variables (not set by default).
enable_autosnippets: Autosnippets are disabled by default to minimize performance penalty if unused. Set to true to enable.
ext_opts: Additional options passed to extmarks. Can be used to add passive/active highlight on a per-node-basis (more info in DOC.md)
parser_nested_assembler: Override the default behaviour of inserting a choiceNode containing the nested snippet and an empty insertNode for nested placeholders ("${1: ${2: this is nested}}"). For an example (behaviour more similar to vscode), check here
ft_func: Source of possible filetypes for snippets. Defaults to a function, which returns vim.split(vim.bo.filetype, ".", true), but check filetype_functions for other options

Inspired by vsnip.vim

againxx / LuaSnip