*mini.surround* Surround actions

MIT License Copyright (c) 2021 Evgeni Chasnovski

------------------------------------------------------------------------------
                                                                  *MiniSurround*
Fast and feature-rich surrounding. Can be configured to have experience
similar to [tpope/vim-surround](https://github.com/tpope/vim-surround)
(see |MiniSurround-vim-surround-config|).

Features:
- Actions (text editing actions are dot-repeatable out of the box and
  respect |[count]|) with configurable mappings:
    - Add surrounding with `sa` (in visual mode or on motion).
    - Delete surrounding with `sd`.
    - Replace surrounding with `sr`.
    - Find surrounding with `sf` or `sF` (move cursor right or left).
    - Highlight surrounding with `sh`.

- Surrounding is identified by a single character as both "input" (in
  `delete` and `replace` start, `find`, and `highlight`) and "output" (in
  `add` and `replace` end):
    - `f` - function call (string of alphanumeric symbols or `_` or `.`
      followed by balanced `()`). In "input" finds function call, in
      "output" prompts user to enter function name.
    - `t` - tag. In "input" finds tag with same identifier, in "output"
      prompts user to enter tag name with possible attributes.
    - All symbols in brackets `()`, `[]`, `{}`, `<>`. In "input" represents
      balanced brackets (open - with whitespace pad, close - without), in
      "output" - left and right parts of brackets.
    - `?` - interactive. Prompts user to enter left and right parts.
    - All other single character identifiers (supported by |getcharstr()|)
      represent surrounding with identical left and right parts.

- Configurable search methods to find not only covering but possibly next,
  previous, or nearest surrounding. See more in |MiniSurround.config|.

- All actions involving finding surrounding (delete, replace, find,
  highlight) can be used with suffix that changes search method to find
  previous/last. See more in |MiniSurround.config|.

Known issues which won't be resolved:
- Search for surrounding is done using Lua patterns (regex-like approach).
  So certain amount of false positives should be expected.

- When searching for "input" surrounding, there is no distinction if it is
  inside string or comment. So in this case there will be not proper match
  for a function call: `f(a = ")", b = 1)`.

- Tags are searched using regex-like methods, so issues are inevitable.
  Overall it is pretty good, but certain cases won't work. Like self-nested
  tags won't match correctly on both ends: `<a><a></a></a>`.

# Setup ~

This module needs a setup with `require('mini.surround').setup({})`
(replace `{}` with your `config` table). It will create global Lua table
`MiniSurround` which you can use for scripting or manually (with
`:lua MiniSurround.*`).

See |MiniSurround.config| for `config` structure and default values.

You can override runtime config settings locally to buffer inside
`vim.b.minisurround_config` which should have same structure as
`MiniSurround.config`. See |mini.nvim-buffer-local-config| for more details.

To stop module from showing non-error feedback, set `config.silent = true`.

# Example usage ~

Regular mappings:
- `saiw)` - add (`sa`) for inner word (`iw`) parenthesis (`)`).
- `saiw?[[<CR>]]<CR>` - add (`sa`) for inner word (`iw`) interactive
  surrounding (`?`): `[[` for left and `]]` for right.
- `2sdf` - delete (`sd`) second (`2`) surrounding function call (`f`).
- `sr)tdiv<CR>` - replace (`sr`) surrounding parenthesis (`)`) with tag
  (`t`) with identifier `div` (`div<CR>` in command line prompt).
- `sff` - find right (`sf`) part of surrounding function call (`f`).
- `sh}` - highlight (`sh`) for a brief period of time surrounding curly
  brackets (`}`).

Extended mappings (temporary force "prev"/"next" search methods):
- `sdnf` - delete (`sd`) next (`n`) function call (`f`).
- `srlf(` - replace (`sr`) last (`l`) function call (`f`) with padded
  bracket (`(`).
- `2sfnt` - find (`sf`) second (`2`) next (`n`) tag (`t`).
- `2shl}` - highlight (`sh`) last (`l`) second (`2`) curly bracket (`}`).

# Comparisons ~

- [tpope/vim-surround](https://github.com/tpope/vim-surround):
    - `vim-surround` has completely different, with other focus set of
      default mappings, while |mini.surround| has a more coherent set.
    - |mini.surround| supports dot-repeat, customized search path (see
      |MiniSurround.config|), customized specifications (see
      |MiniSurround-surrounding-specification|) allowing usage of tree-sitter
      queries (see |MiniSurround.gen_spec.input.treesitter()|),
      highlighting and finding surrounding, "last"/"next" extended
      mappings. While `vim-surround` does not.
- [machakann/vim-sandwich](https://github.com/machakann/vim-sandwich):
    - Both have same keybindings for common actions (add, delete, replace).
    - Otherwise same differences as with `tpope/vim-surround` (except
      dot-repeat because `vim-sandwich` supports it).
- [kylechui/nvim-surround](https://github.com/kylechui/nvim-surround):
    - `nvim-surround` is designed after `tpope/vim-surround` with same
      default mappings and logic, while |mini.surround| has mappings
      similar to `machakann/vim-sandwich`.
    - |mini.surround| has more flexible customization of input surrounding
      (with composed patterns, region pair(s), search methods).
    - |mini.surround| supports |[count]| in both input and output
      surrounding (see |MiniSurround-count-with-actions|) while
      `nvim-surround` doesn't.
    - |mini.surround| supports "last"/"next" extended mappings.
- |mini.ai|:
    - Both use similar logic for finding target: textobject in |mini.ai|
      and surrounding pair in |mini.surround|. While |mini.ai| uses
      extraction pattern for separate `a` and `i` textobjects,
      |mini.surround| uses it to select left and right surroundings
      (basically a difference between `a` and `i` textobjects).
    - Some builtin specifications are slightly different:
        - Quotes in |mini.ai| are balanced, in |mini.surround| they are not.
        - The |mini.surround| doesn't have argument surrounding.
        - Default behavior in |mini.ai| selects one of the edges into `a`
          textobject, while |mini.surround| - both.

# Highlight groups ~
*MiniSurround-hl-groups*

- `MiniSurround` - highlighting of requested surrounding.

To change any highlight group, set it directly with |nvim_set_hl()|.

# Disabling ~

To disable, set `vim.g.minisurround_disable` (globally) or
`vim.b.minisurround_disable` (for a buffer) to `true`. Considering high
number of different scenarios and customization intentions, writing exact
rules for disabling module's functionality is left to user. See
|mini.nvim-disabling-recipes| for common recipes.

------------------------------------------------------------------------------
                                             *MiniSurround-builtin-surroundings*
This table describes all builtin surroundings along with what they
represent. Explanation:
- `Key` represents the surrounding identifier: single character which should
  be typed after action mappings (see "Mappings" in |MiniSurround.config|).
- `Name` is a description of surrounding.
- `Example line` contains a string for which examples are constructed. The
  `*` denotes the cursor position over `a` character.
- `Delete` shows the result of typing `sd` followed by surrounding identifier.
  It aims to demonstrate "input" surrounding which is also used in replace
  with `sr` (surrounding id is typed first), highlight with `sh`, find with
  `sf` and `sF`.
- `Replace` shows the result of typing `sr!` followed by surrounding
  identifier (with possible follow up from user). It aims to demonstrate
  "output" surrounding which is also used in adding with `sa` (followed by
  textobject/motion or in Visual mode).

Example: typing `sd)` with cursor on `*` (covers `a` character) changes line
`!( *a (bb) )!` into `! aa (bb) !`. Typing `sr!)` changes same initial line
into `(( aa (bb) ))`.
>
 ┌───┬───────────────┬───────────────┬─────────────┬─────────────────┐
 │Key│     Name      │  Example line │    Delete   │     Replace     │
 ├───┴───────────────┴───────────────┴─────────────┴─────────────────┤
 ├┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┤
 │ ( │  Balanced ()  │ !( *a (bb) )! │  !aa (bb)!  │ ( ( aa (bb) ) ) │
 │ [ │  Balanced []  │ ![ *a [bb] ]! │  !aa [bb]!  │ [ [ aa [bb] ] ] │
 │ { │  Balanced {}  │ !{ *a {bb} }! │  !aa {bb}!  │ { { aa {bb} } } │
 │ < │  Balanced <>  │ !< *a <bb> >! │  !aa <bb>!  │ < < aa <bb> > > │
 ├┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┤
 │ ) │  Balanced ()  │ !( *a (bb) )! │ ! aa (bb) ! │ (( aa (bb) ))   │
 │ ] │  Balanced []  │ ![ *a [bb] ]! │ ! aa [bb] ! │ [[ aa [bb] ]]   │
 │ } │  Balanced {}  │ !{ *a {bb} }! │ ! aa {bb} ! │ {{ aa {bb} }}   │
 │ > │  Balanced <>  │ !< *a <bb> >! │ ! aa <bb> ! │ << aa <bb> >>   │
 │ b │  Alias for    │ !( *a {bb} )! │ ! aa {bb} ! │ (( aa {bb} ))   │
 │   │  ), ], or }   │               │             │                 │
 ├┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┤
 │ q │  Alias for    │ !'aa'*a'aa'!  │ !'aaaaaa'!  │ "'aa'aa'aa'"    │
 │   │  ", ', or `   │               │             │                 │
 ├┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┤
 │ ? │  User prompt  │ !e * o!       │ ! a !       │ ee a oo         │
 │   │(typed e and o)│               │             │                 │
 ├┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┤
 │ t │      Tag      │ !<x>*</x>!    │ !a!         │ <y><x>a</x></y> │
 │   │               │               │             │ (typed y)       │
 ├┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┤
 │ f │ Function call │ !f(*a, bb)!   │ !aa, bb!    │ g(f(*a, bb))    │
 │   │               │               │             │ (typed g)       │
 ├┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┤
 │   │    Default    │ !_a*a_!       │ !aaa!       │ __aaa__         │
 │   │   (typed _)   │               │             │                 │
 └┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┘
<
Notes:
- All examples assume default `config.search_method`.
- Open brackets differ from close brackets by how they treat inner edge
  whitespace: open includes it left and right parts, close does not.
- Output value of `b` alias is same as `)`. For `q` alias - same as `"`.
- Default surrounding is activated for all characters which are not
  configured surrounding identifiers. Notes:
    - Due to special handling of underlying `x.-x` Lua pattern
      (see |MiniSurround-search-algorithm|), it doesn't really support
      non-trivial `[count]` for "cover" search method.
    - When cursor is exactly on the identifier character while there are
      two matching candidates on both left and right, the one resulting in
      region with smaller width is preferred.

------------------------------------------------------------------------------
                                                         *MiniSurround-glossary*
Note: this is similar to |MiniAi-glossary|.

REGION ~
Table representing region in a buffer. Fields: <from> and <to> for
inclusive start and end positions (<to> might be `nil` to describe empty
region). Each position is also a table with line <line> and column <col>
(both start at 1). Examples: >lua

  { from = { line = 1, col = 1 }, to = { line = 2, col = 1 } }

  -- Empty region
  { from = { line = 10, col = 10 } }
<
REGION PAIR ~
Table representing regions for left and right surroundings. Fields: <left>
and <right> with regions. Example: >lua

  {
    left  = { from = { line = 1, col = 1 }, to = { line = 1, col = 1 } },
    right = { from = { line = 1, col = 3 } },
  }
<
PATTERN ~
String describing Lua pattern.

SPAN ~
Interval inside a string (end-exclusive). Like [1, 5). Equal `from` and `to` edges
describe empty span at that point.

Span `A = [a1, a2)` covers `B = [b1, b2)` if every element of `B` is within
`A` (`a1 <= b < a2`). It also is described as "B is nested inside A".

NESTED PATTERN ~
Array of patterns aimed to describe nested spans.

SPAN MATCHES NESTED PATTERN ~
If there is a sequence of consecutively nested spans each matching
corresponding pattern within substring of previous span (or input string
for first span). Example: >lua

  -- Nested patterns for balanced `()` with inner space
  { '%b()', '^. .* .$' }

  -- Example input string (with columns underneath for easier reading):
     "( ( () ( ) ) )"
  --  12345678901234
<
Here are all matching spans [1, 15) and [3, 13). Both [5, 7) and [8, 10)
match first pattern but not second. All other combinations of `(` and `)`
don't match first pattern (not balanced).

COMPOSED PATTERN ~
Array with each element describing possible pattern (or array of them) at
that place. Composed pattern basically defines all possible combinations of
nested pattern (their cartesian product). Examples:

1. Either balanced `()` or balanced `[]` but both with inner edge space: >lua

    -- Composed pattern
    { { '%b()', '%b[]' }, '^. .* .$' }

    -- Composed pattern expanded into equivalent array of nested patterns
    { '%b()', '^. .* .$' } -- and
    { '%b[]', '^. .* .$' }
<
2. Either "balanced `()` with inner edge space" or "balanced `[]` with no
   inner edge space", both with 5 or more characters: >lua

    -- Composed pattern
    { { { '%b()', '^. .* .$' }, { '%b[]', '^.[^ ].*[^ ].$' } }, '.....' }

    -- Composed pattern expanded into equivalent array of nested patterns
    { '%b()', '^. .* .$', '.....' } -- and
    { '%b[]', '^.[^ ].*[^ ].$', '.....' }
<
SPAN MATCHES COMPOSED PATTERN ~
If it matches at least one nested pattern from expanded composed pattern.

------------------------------------------------------------------------------
                                        *MiniSurround-surrounding-specification*
Surround specification is a table with keys:
- <input> - defines how to find and extract surrounding for "input"
  operations (like `delete`). See more in "Input surrounding" section.
- <output> - defines what to add on left and right for "output" operations
  (like `add`). See more in "Output surrounding" section.

Example of surround info for builtin `)` identifier: >lua

  {
    input = { '%b()', '^.().*().$' },
    output = { left = '(', right = ')' }
  }
<
# Input surrounding ~

Specification for input surrounding has a structure of composed pattern
(see |MiniSurround-glossary|) with two differences:
- Last pattern(s) should have two or four empty capture groups denoting
  how the last string should be processed to extract surrounding parts:
    - Two captures represent left part from start of string to first
      capture and right part - from second capture to end of string.
      Example: `a()b()c` defines left surrounding as `a`, right - `c`.
    - Four captures define left part inside captures 1 and 2, right part -
      inside captures 3 and 4. Example: `a()()b()c()` defines left part as
      empty, right part as `c`.
- Allows callable objects (see |vim.is_callable()|) in certain places
  (enables more complex surroundings in exchange of increase in configuration
  complexity and computations):
    - If specification itself is a callable, it will be called without
      arguments and should return one of:
        - Composed pattern. Useful for implementing user input. Example of
          simplified variant of input surrounding for function call with
          name taken from user prompt: >lua

            function()
              local left_edge = vim.pesc(vim.fn.input('Function name: '))
              return { left_edge .. '%b()', '^.-%(().*()%)$' }
            end
<
        - Single region pair (see |MiniSurround-glossary|). Useful to allow
          full control over surrounding. Will be taken as is. Example of
          returning first and last lines of a buffer: >lua

            function()
              local n_lines = vim.fn.line('$')
              return {
                left = {
                  from = { line = 1, col = 1 },
                  to = { line = 1, col = vim.fn.getline(1):len() }
                },
                right = {
                  from = { line = n_lines, col = 1 },
                  to = { line = n_lines, col = vim.fn.getline(n_lines):len() }
                },
              }
            end
<
        - Array of region pairs. Useful for incorporating other instruments,
          like treesitter (see |MiniSurround.gen_spec.input.treesitter()|). The
          best region pair will be picked in the same manner as with composed
          pattern (respecting options `n_lines`, `search_method`, etc.) using
          output region (from start of left region to end of right region).
          Example using edges of "best" line with display width more than 80: >lua

            function()
              local make_line_region_pair = function(n)
                local left = { line = n, col = 1 }
                local right = { line = n, col = vim.fn.getline(n):len() }
                return {
                  left = { from = left, to = left },
                  right = { from = right, to = right },
                }
              end

              local res = {}
              for i = 1, vim.fn.line('$') do
                if vim.fn.getline(i):len() > 80 then
                  table.insert(res, make_line_region_pair(i))
                end
              end
              return res
            end
<
    - If there is a callable instead of assumed string pattern, it is expected
      to have signature `(line, init)` and behave like `pattern:find()`.
      It should return two numbers representing span in `line` next after
      or at `init` (`nil` if there is no such span).
      !IMPORTANT NOTE!: it means that output's `from` shouldn't be strictly
      to the left of `init` (it will lead to infinite loop). Not allowed as
      last item (as it should be pattern with captures).
      Example of matching only balanced parenthesis with big enough width: >lua

        {
          '%b()',
          function(s, init)
            if init > 1 or s:len() < 5 then return end
            return 1, s:len()
          end,
          '^.().*().$'
        }
<
More examples: >lua

  -- Pair of balanced brackets from set (used for builtin `b` identifier)
  { { '%b()', '%b[]', '%b{}' }, '^.().*().$' }

  -- Lua block string
  { '%[%[().-()%]%]' }
<
See |MiniSurround.gen_spec| for function wrappers to create commonly used
surrounding specifications.

# Output surrounding ~

Specification for output can be either a table with <left> and <right> fields,
or a callable returning such table (will be called with no arguments).
Strings can contain new lines character "\n" to add multiline parts.

Examples: >lua

  -- Lua block string
  { left = '[[', right = ']]' }

  -- Brackets on separate lines (indentation is not preserved)
  { left = '(\n', right = '\n)' }

  -- Function call
  function()
    local function_name = MiniSurround.user_input('Function name')
    return { left = function_name .. '(', right = ')' }
  end
<
------------------------------------------------------------------------------
                                               *MiniSurround-count-with-actions*
|[count]| is supported by all actions in the following ways:

- In add, two types of `[count]` is supported in Normal mode:
  `[count1]sa[count2][textobject]`. The `[count1]` defines how many times
  left and right parts of output surrounding will be repeated and `[count2]` is
  used for textobject.
  In Visual mode `[count]` is treated as `[count1]`.
  Example: `2sa3aw)` and `v3aw2sa)` will result into textobject `3aw` being
  surrounded by `((` and `))`.

- In delete/replace/find/highlight `[count]` means "find n-th surrounding
  and execute operator on it".
  Example: `2sd)` on line `(a(b(c)b)a)` with cursor on `c` will result into
  `(ab(c)ba)` (and not in `(abcba)` if it would have meant "delete n times").

------------------------------------------------------------------------------
                                                 *MiniSurround-search-algorithm*
Search for the input surrounding relies on these principles:
- Input surrounding specification is constructed based on surrounding
  identifier (see |MiniSurround-surrounding-specification|).
- General search is done by converting some 2d buffer region (neighborhood
  of reference region) into 1d string (each line is appended with `\n`).
  Then search for a best span matching specification is done inside string
  (see |MiniSurround-glossary|). After that, span is converted back into 2d
  region. Note: first search is done inside reference region lines, and
  only after that - inside its neighborhood within `config.n_lines` (see
  |MiniSurround.config|).
- The best matching span is chosen by iterating over all spans matching
  surrounding specification and comparing them with "current best".
  Comparison also depends on reference region (tighter covering is better,
  otherwise closer is better) and search method (if span is even considered).
- Extract pair of spans (for left and right regions in region pair) based
  on extraction pattern (last item in nested pattern).
- For |[count]| greater than 1, steps are repeated with current best match
  becoming reference region. One such additional step is also done if final
  region is equal to reference region.

Notes:
- Iteration over all matched spans is done in depth-first fashion with
  respect to nested pattern.
- It is guaranteed that span is compared only once.
- For the sake of increasing functionality, during iteration over all
  matching spans, some Lua patterns in composed pattern are handled
  specially.
    - `%bxx` (`xx` is two identical characters). It denotes balanced pair
      of identical characters and results into "paired" matches. For
      example, `%b""` for `"aa" "bb"` would match `"aa"` and `"bb"`, but
      not middle `" "`.
    - `x.-y` (`x` and `y` are different strings). It results only in matches with
      smallest width. For example, `e.-o` for `e e o o` will result only in
      middle `e o`. Note: it has some implications for when parts have
      quantifiers (like `+`, etc.), which usually can be resolved with
      frontier pattern `%f[]`.

------------------------------------------------------------------------------
                                                          *MiniSurround.setup()*
                         `MiniSurround.setup`({config})
Module setup

Parameters ~
{config} `(table|nil)` Module config table. See |MiniSurround.config|.

Usage ~
>lua
  require('mini.surround').setup() -- use default config
  -- OR
  require('mini.surround').setup({}) -- replace {} with your config table
<
------------------------------------------------------------------------------
                                                           *MiniSurround.config*
                             `MiniSurround.config`
Defaults ~
>lua
  MiniSurround.config = {
    -- Custom surroundings to be used on top of builtin ones.
    -- For more information with examples, see `:h MiniSurround.config`.
    custom_surroundings = {},

    -- Duration (in ms) of highlight when calling `MiniSurround.highlight()`
    highlight_duration = 500,

    -- Module mappings. Use `''` (empty string) to disable one.
    mappings = {
      add = 'sa', -- Add surrounding in Normal and Visual modes
      delete = 'sd', -- Delete surrounding
      find = 'sf', -- Find surrounding (to the right)
      find_left = 'sF', -- Find surrounding (to the left)
      highlight = 'sh', -- Highlight surrounding
      replace = 'sr', -- Replace surrounding

      suffix_last = 'l', -- Suffix to search with "prev" method
      suffix_next = 'n', -- Suffix to search with "next" method
    },

    -- Number of lines within which surrounding is searched
    n_lines = 20,

    -- Whether to respect selection type:
    -- - Place surroundings on separate lines in linewise mode.
    -- - Place surroundings on each line in blockwise mode.
    respect_selection_type = false,

    -- How to search for surrounding (first inside current line, then inside
    -- neighborhood). One of 'cover', 'cover_or_next', 'cover_or_prev',
    -- 'cover_or_nearest', 'next', 'prev', 'nearest'. For more details,
    -- see `:h MiniSurround.config`.
    search_method = 'cover',

    -- Whether to disable showing non-error feedback
    -- This also affects (purely informational) helper messages shown after
    -- idle time if user input is required.
    silent = false,
  }
<
# Mappings ~

`config.mappings` defines what mappings are set up for particular actions.
By default it uses "prefix style" left hand side starting with "s" (for
"surround"): `sa` - "surround add", `sd` - "surround delete", etc.

Note: if any of the mappings start with "s" (as is by default), it is mapped
to |<Nop>| to prevent accidental trigger of built-in |s| (can happen if there
is a long enough delay between pressing "s" and the next key). Use `cl` instead.

# Custom surroundings ~

User can define own surroundings by supplying `config.custom_surroundings`.
It should be a table with keys being single character surrounding
identifier (supported by |getcharstr()|) and values - surround specification
(see |MiniSurround-surrounding-specification|).

General recommendations:
- In `config.custom_surroundings` only some data can be defined (like only
  `output`). Other fields will be taken from builtin surroundings.
- Function returning surround info at <input> or <output> fields of
  specification is helpful when user input is needed (like asking for
  function name). Use |MiniSurround.user_input()| or |MiniInput.get()|.
  Return `nil` to stop any current surround operation.
- Keys should use character representation which can be |getcharstr()| output.
  For example, `'\r'` and not `'<CR>'`.

Examples of using `config.custom_surroundings` (see more examples at
|MiniSurround.gen_spec|): >lua

  local surround = require('mini.surround')
  surround.setup({
    custom_surroundings = {
      -- Make `)` insert parts with spaces. `input` pattern stays the same.
      [')'] = { output = { left = '( ', right = ' )' } },

      -- Use function to compute surrounding info
      ['*'] = {
        input = function()
          local n_star = MiniSurround.user_input('Number of * to find')
          local many_star = string.rep('%*', tonumber(n_star) or 1)
          return { many_star .. '().-()' .. many_star }
        end,
        output = function()
          local n_star = MiniSurround.user_input('Number of * to output')
          local many_star = string.rep('*', tonumber(n_star) or 1)
          return { left = many_star, right = many_star }
        end,
      },
    },
  })

  -- Create custom surrounding for Lua's block string `[[...]]`
  -- Use this inside autocommand or 'after/ftplugin/lua.lua' file
  vim.b.minisurround_config = {
    custom_surroundings = {
      s = {
        input = { '%[%[().-()%]%]' },
        output = { left = '[[', right = ']]' },
      },
    },
  }
<
# Respect selection type ~

Boolean option `config.respect_selection_type` controls whether to respect
selection type when adding and deleting surrounding. When enabled:
- Linewise adding places surroundings on separate lines while indenting
  surrounded lines ones.
- Deleting surroundings which look like they were the result of linewise
  adding will act to revert it: delete lines with surroundings and dedent
  surrounded lines ones.
- Blockwise adding places surroundings on whole edges, not only start and
  end of selection. Note: it doesn't really work outside of text and in
  presence of multibyte characters; and probably won't due to
  implementation difficulties.

# Search method ~

Value of `config.search_method` defines how best match search is done.
Based on its value, one of the following matches will be selected:
- Covering match. Left/right edge is before/after left/right edge of
  reference region.
- Previous match. Left/right edge is before left/right edge of reference
  region.
- Next match. Left/right edge is after left/right edge of reference region.
- Nearest match. Whichever is closest among previous and next matches.

Possible values are:
- `'cover'` (default) - use only covering match. Don't use either previous or
  next; report that there is no surrounding found.
- `'cover_or_next'` - use covering match. If not found, use next.
- `'cover_or_prev'` - use covering match. If not found, use previous.
- `'cover_or_nearest'` - use covering match. If not found, use nearest.
- `'next'` - use next match.
- `'previous'` - use previous match.
- `'nearest'` - use nearest match.

Note: search is first performed on the reference region lines and only
after failure - on the whole neighborhood defined by `config.n_lines`. This
means that with `config.search_method` not equal to `'cover'`, "previous"
or "next" surrounding will end up as search result if they are found on
first stage although covering match might be found in bigger, whole
neighborhood. This design is based on observation that most of the time
operation is done within reference region lines (usually cursor line).

Here is an example of how replacing `)` with `]` surrounding is done based
on a value of `'config.search_method'` when cursor is inside `bbb` word:
- `'cover'`:         `(a) bbb (c)` -> `(a) bbb (c)` (with message)
- `'cover_or_next'`: `(a) bbb (c)` -> `(a) bbb [c]`
- `'cover_or_prev'`: `(a) bbb (c)` -> `[a] bbb (c)`
- `'cover_or_nearest'`: depends on cursor position.
  For first and second `b` - as in `cover_or_prev` (as previous match is
  nearer), for third - as in `cover_or_next` (as next match is nearer).
- `'next'`:          `(a) bbb (c)` -> `(a) bbb [c]`. Same outcome for `(bbb)`.
- `'prev'`:          `(a) bbb (c)` -> `[a] bbb (c)`. Same outcome for `(bbb)`.
- `'nearest'`: depends on cursor position (same as in `'cover_or_nearest'`).

# Search suffixes ~

To provide more searching possibilities, |mini.surround| creates extended
mappings force "prev" and "next" methods for particular search. It does so
by appending mapping with certain suffix: `config.mappings.suffix_last` for
mappings which will use "prev" search method, `config.mappings.suffix_next`
- "next" search method.

Notes:
- It creates new mappings only for actions involving surrounding search:
  delete, replace, find (right and left), highlight.
- All new mappings behave the same way as if `config.search_method` is set
  to certain search method. They preserve dot-repeat support, respect |[count]|.
- Supply empty string to disable creation of corresponding set of mappings.

Example with default values (`n` for `suffix_next`, `l` for `suffix_last`)
and initial line `(aa) (bb) (cc)`.
- Typing `sdn)` with cursor inside `(aa)` results into `(aa) bb (cc)`.
- Typing `sdl)` with cursor inside `(cc)` results into `(aa) bb (cc)`.
- Typing `2srn)]` with cursor inside `(aa)` results into `(aa) (bb) [cc]`.

# Setup similar to `tpope/vim-surround` ~
*MiniSurround-vim-surround-config*

This module is primarily designed after `machakann/vim-sandwich`. To get
behavior closest to `tpope/vim-surround` (but not identical), use this setup: >lua

  require('mini.surround').setup({
    mappings = {
      add = 'ys',
      delete = 'ds',
      find = '',
      find_left = '',
      highlight = '',
      replace = 'cs',

      -- Add this only if you don't want to use extended mappings
      suffix_last = '',
      suffix_next = '',
    },
    search_method = 'cover_or_next',
  })

  -- Remap adding surrounding to Visual mode selection
  vim.keymap.del('x', 'ys')
  vim.keymap.set('x', 'S', [[:<C-u>lua MiniSurround.add('visual')<CR>]], { silent = true })

  -- Make special mapping for "add surrounding for line"
  vim.keymap.set('n', 'yss', 'ys_', { remap = true })
<
------------------------------------------------------------------------------
                                                            *MiniSurround.add()*
                           `MiniSurround.add`({mode})
Add surrounding

No need to use it directly, everything is setup in |MiniSurround.setup()|.

Parameters ~
{mode} `(string)` Mapping mode (normal by default).

------------------------------------------------------------------------------
                                                         *MiniSurround.delete()*
                            `MiniSurround.delete`()
Delete surrounding

No need to use it directly, everything is setup in |MiniSurround.setup()|.

------------------------------------------------------------------------------
                                                        *MiniSurround.replace()*
                            `MiniSurround.replace`()
Replace surrounding

No need to use it directly, everything is setup in |MiniSurround.setup()|.

------------------------------------------------------------------------------
                                                           *MiniSurround.find()*
                             `MiniSurround.find`()
Find surrounding

No need to use it directly, everything is setup in |MiniSurround.setup()|.

------------------------------------------------------------------------------
                                                      *MiniSurround.highlight()*
                           `MiniSurround.highlight`()
Highlight surrounding

No need to use it directly, everything is setup in |MiniSurround.setup()|.

------------------------------------------------------------------------------
                                                 *MiniSurround.update_n_lines()*
                        `MiniSurround.update_n_lines`()
Update `MiniSurround.config.n_lines` from user input

Mapping example: >lua

  vim.keymap.set('n', 'sn', '<Cmd>lua MiniSurround.update_n_lines()<CR>')
<
------------------------------------------------------------------------------
                                                     *MiniSurround.user_input()*
                  `MiniSurround.user_input`({prompt}, {text})
Ask user for input

This is mainly a wrapper for |input()| which allows empty string as input,
cancelling with `<Esc>` and `<C-c>`, and slightly modifies prompt. Use it
to ask for input inside function custom surrounding (see |MiniSurround.config|).

------------------------------------------------------------------------------
                                                         *MiniSurround.gen_spec*
                            `MiniSurround.gen_spec`
Generate common surrounding specifications

This is a table with two sets of generator functions: <input> and <output>
(currently empty). Each is a table with function values generating
corresponding surrounding specification.

See also ~
|MiniAi.gen_spec|

------------------------------------------------------------------------------
                                      *MiniSurround.gen_spec.input.treesitter()*
          `MiniSurround.gen_spec.input.treesitter`({captures}, {opts})
Treesitter specification for input surrounding

This is a specification in function form. When called with a pair of
treesitter captures, it returns a specification function outputting an
array of region pairs derived from <outer> and <inner> captures. It first
searches for all matched nodes of outer capture and then completes each one
with the biggest match of inner capture inside that node (if any). The result
region pair is a difference between regions of outer and inner captures.

In order for this to work, apart from working treesitter parser for desired
language, user should have a reachable language-specific `'textobjects'`
query (see |vim.treesitter.query.get()|).
The most straightforward way for this is to have `textobjects.scm` query
file with treesitter captures stored in some recognized path. This is
primarily designed to be compatible with plugin
`nvim-treesitter/nvim-treesitter-textobjects`, but can be used without it.

Two most common approaches for having a query file:
- Install `nvim-treesitter/nvim-treesitter-textobjects`. It has curated and
  well maintained builtin query files for many languages with a standardized
  capture names, like `call.outer`, `call.inner`, etc.
- Manually create file `after/queries/<language-name>/textobjects.scm` in
  your |$XDG_CONFIG_HOME| directory. It should contain queries with
  captures (later used to define surrounding parts). See |lua-treesitter-query|.
To verify that query file is reachable, run (example for "lua" language,
output should have at least an intended file): >vim

  :lua print(vim.inspect(vim.treesitter.query.get_files('lua','textobjects')))
<
Example configuration for function definition textobject with
`nvim-treesitter/nvim-treesitter-textobjects` captures: >lua

  local ts_input = require('mini.surround').gen_spec.input.treesitter
  require('mini.surround').setup({
    custom_surroundings = {
      -- Use tree-sitter to search for function call
      f = {
        input = ts_input({ outer = '@call.outer', inner = '@call.inner' })
      },
    }
  })
<
Notes:
- Be sure that query files don't contain unknown |treesitter-directives|
  (like `#make-range!`, for example). Otherwise surrounding with such captures
  might not be found as |lua-treesitter-core| won't treat them as captures.
  Verify with `:=vim.treesitter.query.get('lang', 'textobjects')` and see
  if the target capture is recognized as one.
- It uses buffer's |filetype| to determine query language.
- It first searches the language under cursor for matches. If no matches are
  found, it falls back to searching parent languages (up to the buffer's root
  language). If no matches are found again, it falls back to recursively
  searching all children languages (from the language under cursor). If no
  matches again - report no matches.
- On large files it is slower than pattern-based textobjects. Still very
  fast though (one search should be magnitude of milliseconds or tens of
  milliseconds on really large file).

Parameters ~
{captures} `(table)` Captures for outer and inner parts of region pair:
  table with <outer> and <inner> fields with captures for outer
  (`[left.form; right.to]`) and inner (`(left.to; right.from)` both edges
  exclusive, i.e. they won't be a part of surrounding) regions. Each value
  should be a string capture starting with `'@'`.
{opts} `(table|nil)` Options. Possible values:
  - <use_nvim_treesitter> - whether to try to use `nvim-treesitter` plugin
    (if present) to do the query. It used to implement more advanced behavior
    and more coherent experience if `nvim-treesitter-textobjects` queries are
    used. However, as |lua-treesitter-core| methods are more capable now,
    the option will soon be removed. Only present for backward compatibility.
    Default: `false`.

Return ~
`(function)` Function which returns array of current buffer region pairs
  representing differences between outer and inner captures.

See also ~
- |MiniSurround-surrounding-specification| for how this type of
  surrounding specification is processed.
- |vim.treesitter.query.get()| for how query is fetched.
- |Query:iter_captures()| for how all query captures are iterated in case of
  no `nvim-treesitter`.
- |MiniAi.gen_spec.treesitter()| for similar |mini.ai| generator.


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