nvim-paredit

A Paredit implementation for Neovim, built using Treesitter and written in Lua.

The goal of nvim-paredit is to provide a comparable s-expression editing experience in Neovim to that provided by Emacs. This is what is provided:

Treesitter based lisp structural editing, cursor motions and text object selections
Dot-repeatable keybindings
Language extensibility
Programmable API

Index

Installation
Configuration
API Reference
Recipes
Auto Indentation
Pairwise Dragging
Language Support
- Language Queries Spec
Prior Art

Installation

Using folke/lazy.vim

{
  "julienvincent/nvim-paredit",
  config = function()
    require("nvim-paredit").setup()
  end
}

Configuration

local paredit = require("nvim-paredit")
paredit.setup({
  -- Change some keys
  keys = {
    ["<localleader>o"] = false,
    ["<localleader>r"] = { paredit.api.raise_form, "Raise form" },
  },
})

Default Configuration Values

local paredit = require("nvim-paredit")
paredit.setup({
  -- Should plugin use default keybindings? (default = true)
  use_default_keys = true,
  -- Sometimes user wants to restrict plugin to certain filetypes only or add support
  -- for new filetypes.
  --
  -- Defaults to all supported filetypes.
  filetypes = { "clojure", "fennel", "scheme", "lisp" },

  -- This is some language specific configuration. Right now this is just used for
  -- setting character lists that are considered whitespace.
  languages = {
    clojure = {
      whitespace_chars = { " ", "," },
    },
    fennel = {
      whitespace_chars = { " ", "," },
    },
  },

  -- This controls where the cursor is placed when performing slurp/barf operations
  --
  -- - "remain" - It will never change the cursor position, keeping it in the same place
  -- - "follow" - It will always place the cursor on the form edge that was moved
  -- - "auto"   - A combination of remain and follow, it will try keep the cursor in the original position
  --              unless doing so would result in the cursor no longer being within the original form. In
  --              this case it will place the cursor on the moved edge
  cursor_behaviour = "auto", -- remain, follow, auto

  dragging = {
    -- If set to `true` paredit will attempt to infer if an element being
    -- dragged is part of a 'paired' form like as a map. If so then the element
    -- will be dragged along with it's pair.
    auto_drag_pairs = true,
  },

  indent = {
    -- This controls how nvim-paredit handles indentation when performing operations which
    -- should change the indentation of the form (such as when slurping or barfing).
    --
    -- When set to true then it will attempt to fix the indentation of nodes operated on.
    enabled = false,
    -- A function that will be called after a slurp/barf if you want to provide a custom indentation
    -- implementation.
    indentor = require("nvim-paredit.indentation.native").indentor,
  },

  -- list of default keybindings
  keys = {
    ["<localleader>@"] = { paredit.unwrap.unwrap_form_under_cursor, "Splice sexp" },
    [">)"] = { paredit.api.slurp_forwards, "Slurp forwards" },
    [">("] = { paredit.api.barf_backwards, "Barf backwards" },

    ["<)"] = { paredit.api.barf_forwards, "Barf forwards" },
    ["<("] = { paredit.api.slurp_backwards, "Slurp backwards" },

    [">e"] = { paredit.api.drag_element_forwards, "Drag element right" },
    ["<e"] = { paredit.api.drag_element_backwards, "Drag element left" },

    [">p"] = { api.drag_pair_forwards, "Drag element pairs right" },
    ["<p"] = { api.drag_pair_backwards, "Drag element pairs left" },

    [">f"] = { paredit.api.drag_form_forwards, "Drag form right" },
    ["<f"] = { paredit.api.drag_form_backwards, "Drag form left" },

    ["<localleader>o"] = { paredit.api.raise_form, "Raise form" },
    ["<localleader>O"] = { paredit.api.raise_element, "Raise element" },

    ["E"] = {
      paredit.api.move_to_next_element_tail,
      "Jump to next element tail",
      -- by default all keybindings are dot repeatable
      repeatable = false,
      mode = { "n", "x", "o", "v" },
    },
    ["W"] = {
      paredit.api.move_to_next_element_head,
      "Jump to next element head",
      repeatable = false,
      mode = { "n", "x", "o", "v" },
    },

    ["B"] = {
      paredit.api.move_to_prev_element_head,
      "Jump to previous element head",
      repeatable = false,
      mode = { "n", "x", "o", "v" },
    },
    ["gE"] = {
      paredit.api.move_to_prev_element_tail,
      "Jump to previous element tail",
      repeatable = false,
      mode = { "n", "x", "o", "v" },
    },

    ["("] = {
      paredit.api.move_to_parent_form_start,
      "Jump to parent form's head",
      repeatable = false,
      mode = { "n", "x", "v" },
    },
    [")"] = {
      paredit.api.move_to_parent_form_end,
      "Jump to parent form's tail",
      repeatable = false,
      mode = { "n", "x", "v" },
    },

    -- These are text object selection keybindings which can used with standard `d, y, c`, `v`
    ["af"] = {
      paredit.api.select_around_form,
      "Around form",
      repeatable = false,
      mode = { "o", "v" },
    },
    ["if"] = {
      paredit.api.select_in_form,
      "In form",
      repeatable = false,
      mode = { "o", "v" },
    },
    ["aF"] = {
      paredit.api.select_around_top_level_form,
      "Around top level form",
      repeatable = false,
      mode = { "o", "v" },
    },
    ["iF"] = {
      paredit.api.select_in_top_level_form,
      "In top level form",
      repeatable = false,
      mode = { "o", "v" },
    },
    ["ae"] = {
      paredit.api.select_element,
      "Around element",
      repeatable = false,
      mode = { "o", "v" },
    },
    ["ie"] = {
      paredit.api.select_element,
      "Element",
      repeatable = false,
      mode = { "o", "v" },
    },
  },
})

API Reference

See api-reference.md

Auto Indentation

Nvim-paredit comes with built-in support for fixing form indentation when performing slurp and barf operations. By default, this behaviour is disabled and can be enabled by setting indent.enabled = true in the configuration

The main goal of this implementation is to provide a visual aid to the user, allowing them to confirm they are operating on the correct node and to know when to stop when performing recursive slurp/barf operations. This implementation is fast and does not result in any UI lag or jitter.

The goal is not to be 100% correct. The implementation follows a simple set of rules which account for most scenarios but not all. If a more correct implementation is needed then the native implementation can be replaced by setting the configuration property intent.indentor.

For example an implementation using vim.lsp.buf.format could be built if you don't mind sacrificing performance for correctness. See the lsp indentation recipe for an example of this.

Pairwise Dragging

Nvim-paredit has support for dragging elements pairwise. If an element being dragged is within a form that contains pairs of elements (such as a Clojure map) then the element will be dragged along with its pair.

For example:

{:a 1
 |:b 2}
;; Drag backwards
{|:b 2
 :a 1}

This is enabled by default and can be disabled by setting dragging.auto_drag_pairs = false in the configuration.

Pairwise dragging works using treesitter queries to identify element pairs within some localized node. This means you can very easily extend the paredit pairwise implementation by simply adding new treesitter queries to your nvim configuration.

You might want to extend if:

You are a language extension author and want to add pairwise dragging support to your extension.
You want to add support for some syntax not supported by nvim-paredit.

This is especially useful if you have your own Clojure macros that you want to enable pairwise dragging on.

All you need to do to extend is to add a new file called queries/<language>/paredit/pairs.scm in your nvim config directory. Make sure to include the ;; extends directive to the file, or you will overwrite any pre-existing queries defined by nvim-paredit or other language extensions.

See the custom macro pairwise dragging recipe for an example of how to add pairwise dragging support for new syntax

Language Support

As this is built using Treesitter it requires that you have the relevant Treesitter grammar installed for your language of choice. Additionally, nvim-paredit will need explicit support for the treesitter grammar used by your language as the node names and metadata of nodes vary between languages.

Language support is added by providing treesitter query files that specify specific captures nvim-paredit can use to understand the AST.

Right now nvim-paredit has built-in support for:

clojure
fennel *
scheme *
commonlisp *

Note

Items marked with * only have partial test coverage. Not all language syntax is guaranteed to work.

Take a look at the Language Queries Spec if you are wanting to add support for languages not built-in to nvim-paredit, or you want to develop on the existing queries.

Prior Art

vim-sexp

Historically this was the de-facto s-expression editing plugin. Supports a wider range of motions than nvim-paredit but otherwise significantly less functionality.

The main reasons you might want to consider nvim-paredit instead are:

Easier configuration and an exposed Lua API
Control over how the cursor is moved during slurp/barf. (For example if you don't want the cursor to always be moved)
Recursive slurp/barf operations. If your cursor is in a nested form you can still slurp from the forms parent(s)
Automatic form/element indentations on slurp/barf
Pairwise element dragging
Subjectively better out-of-the-box keybindings

vim-sexp-mappings-for-regular-people

A companion to vim-sexp which configures vim-sexp with better mappings. The default mappings for nvim-paredit were derived from here.