*mini.splitjoin* Split and join arguments
*MiniSplitjoin*

MIT License Copyright (c) 2023 Evgeni Chasnovski

==============================================================================

Features:
- Mappings and Lua functions that modify arguments (regions inside brackets
  between allowed separators) under cursor.

  Supported actions:
    - Toggle - split if arguments are on single line, join otherwise.
      Main supported function of the module. See |MiniSplitjoin.toggle()|.
    - Split - make every argument separator be on end of separate line.
      See |MiniSplitjoin.split()|.
    - Join - make all arguments be on single line.
      See |MiniSplitjoin.join()|.

- Mappings are dot-repeatable in Normal mode and work in Visual mode.

- Customizable argument detection (see |MiniSplitjoin.config.detect|):
    - Which brackets can contain arguments.
    - Which strings can separate arguments.
    - Which regions are excluded when looking for separators (like inside
      nested brackets or quotes).

- Customizable pre and post hooks for both split and join. See `split` and
  `join` in |MiniSplitjoin.config|. There are several built-in ones
  in |MiniSplitjoin.gen_hook|.

- Works inside comments by using modified notion of indent.
  See |MiniSplitjoin.get_indent_part()|.

- Provides low-level Lua functions for split and join at positions.
  See |MiniSplitjoin.split_at()| and |MiniSplitjoin.join_at()|.

Notes:
- Search for arguments is done using Lua patterns (regex-like approach).
  Certain amount of false positives is to be expected.

- This module is mostly designed around |MiniSplitjoin.toggle()|. If target
  split positions are on different lines, join first and then split.

- Actions can be done on Visual mode selection, which mostly present as
  a safety route in case of incorrect detection of initial region.
  It uses |MiniSplitjoin.get_visual_region()| which treats selection as full
  brackets (include brackets in selection).

# Setup ~

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

See |MiniSplitjoin.config| for available config settings.

You can override runtime config settings (like action hooks) locally to
buffer inside `vim.b.minisplitjoin_config` which should have same structure
as `MiniSplitjoin.config`. See |mini.nvim-buffer-local-config| for more details.

# Comparisons ~

- 'FooSoft/vim-argwrap':
    - Mostly has the same design as this module.
    - Doesn't work inside comments, while this module does.
    - Has more built-in ways to control split and join, while this module
      intentionally provides only handful.
- 'AndrewRadev/splitjoin.vim':
    - More oriented towards language-depended transformations, while this
      module intntionally deals with more generic text-related functionality.
- 'Wansmer/treesj':
    - Operates based on tree-sitter nodes. This is more accurate in
      some edge cases, but **requires** tree-sitter parser.
    - Doesn't work inside comments or strings.

# Disabling ~

To disable, set `g:minisplitjoin_disable` (globally) or `b:minisplitjoin_disable`
(for a buffer) to `v: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.

------------------------------------------------------------------------------
                                                        *MiniSplitjoin-glossary*
- POSITION - table with fields <line> and <col> containing line and column
  numbers respectively. Both are 1-indexed. Example: `{ line = 2, col = 1 }`.

- REGION - table representing region in a buffer. Fields: <from> and <to> for
  inclusive start and end positions. Example: >lua

  { from = { line = 1, col = 1 }, to = { line = 2, col = 1 } }
<
------------------------------------------------------------------------------
                                                         *MiniSplitjoin.setup()*
                        `MiniSplitjoin.setup`({config})
Module setup

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

Usage ~
>lua
  require('mini.splitjoin').setup() -- use default config
  -- OR
  require('mini.splitjoin').setup({}) -- replace {} with your config table
<
------------------------------------------------------------------------------
                                                          *MiniSplitjoin.config*
                             `MiniSplitjoin.config`
Module config

Default values:
>lua
  MiniSplitjoin.config = {
    -- Module mappings. Use `''` (empty string) to disable one.
    -- Created for both Normal and Visual modes.
    mappings = {
      toggle = 'gS',
      split = '',
      join = '',
    },

    -- Detection options: where split/join should be done
    detect = {
      -- Array of Lua patterns to detect region with arguments.
      -- Default: { '%b()', '%b[]', '%b{}' }
      brackets = nil,

      -- String Lua pattern defining argument separator
      separator = ',',

      -- Array of Lua patterns for sub-regions to exclude separators from.
      -- Enables correct detection in presence of nested brackets and quotes.
      -- Default: { '%b()', '%b[]', '%b{}', '%b""', "%b''" }
      exclude_regions = nil,
    },

    -- Split options
    split = {
      hooks_pre = {},
      hooks_post = {},
    },

    -- Join options
    join = {
      hooks_pre = {},
      hooks_post = {},
    },
  }
<
                                                   *MiniSplitjoin.config.detect*
# Detection ~

The table at `config.detect` controls how arguments are detected using Lua
patterns. General idea is to convert whole buffer into a single line,
perform string search, and convert results back into 2d positions.

Example configuration: >lua

  require('mini.splitjoin').setup({
    detect = {
      -- Detect only inside balanced parenthesis
      brackets = { '%b()' },

      -- Allow both `,` and `;` to separate arguments
      separator = '[,;]',

      -- Make any separator define an argument
      exclude_regions = {},
    },
  })
<
## Outer brackets ~

`detect.brackets` is an array of Lua patterns used to find enclosing region.
It is done by traversing whole buffer to find the smallest region matching
any supplied pattern.

Default: `nil`, inferred as `{ '%b()', '%b[]', '%b{}' }`.
So an argument can be inside a balanced `()`, `[]`, or `{}`.

Example: `brackets = { '%b()' }` will search for arguments only inside
balanced `()`.

## Separator ~

`detect.separator` is a single Lua pattern defining which strings should be
treated as argument separators.

Empty string in `detect.separator` will result in only surrounding brackets
used as separators.

Only end of pattern match will be used as split/join positions.

Default: `','`. So an argument can be separated only with comma.

Example: `separator = { '[,;]' }` will treat both `,` and `;` as separators.

## Excluded regions ~

`detect.exclude_regions` is an array of Lua patterns for sub-regions from which
to exclude separators. Enables correct detection in case of nested brackets
and quotes.

Default: `nil`; inferred as `{ '%b()', '%b[]', '%b{}', '%b""', "%b''" }`.
So a separator **can not** be inside a balanced `()`, `[]`, `{}` (representing
nested argument regions) or `""`, `''` (representing strings).

Example: `exclude_regions = {}` will not exclude any regions. So in case of
`f(a, { b, c })` it will detect both commas as argument separators.

# Hooks ~

`split.hooks_pre`, `split.hooks_post`, `join.hooks_pre`, and `join.hooks_post`
are arrays of hook functions. If empty (default) no hook is applied.

Hooks should take and return array of positions. See |MiniSplitjoin-glossary|.

They can be used to tweak actions:

- Pre-hooks are called before action. Each is applied on the output of
  previous one. Input of first hook are detected split/join positions.
  Output of last one is actually used to perform split/join.

- Post-hooks are called after action. Each is applied on the output of
  previous one. Input of first hook are split/join positions from actual
  action plus its region's right end as last position (for easier hook code).
  Output of last one is used as action return value.

For more specific details see |MiniSplitjoin.split()| and |MiniSplitjoin.join()|.

See |MiniSplitjoin.gen_hook| for generating common hooks with examples.

------------------------------------------------------------------------------
                                                        *MiniSplitjoin.toggle()*
                         `MiniSplitjoin.toggle`({opts})
Toggle arguments

Overview:
- Detect region at input position: either by using supplied `opts.region` or
  by finding smallest bracketed region surrounding position.
  See |MiniSplitjoin.config.detect| for more details.
- If region spans single line, use |MiniSplitjoin.split()| with found region.
  Otherwise use |MiniSplitjoin.join()|.

Parameters ~
{opts} `(table|nil)` Options. Has structure from |MiniSplitjoin.config|
  inheriting its default values.

  Following extra optional fields are allowed:
  - <position> `(table)` - position at which to find smallest bracket region.
    See |MiniSplitjoin-glossary| for the structure.
    Default: cursor position.
  - <region> `(table)` - region at which to perform action. Assumes inclusive
    both start at left bracket and end at right bracket.
    See |MiniSplitjoin-glossary| for the structure.
    Default: `nil` to automatically detect region.

Return ~
`(any)` Output of chosen `split()` or `join()` action.

------------------------------------------------------------------------------
                                                         *MiniSplitjoin.split()*
                         `MiniSplitjoin.split`({opts})
Split arguments

Overview:
- Detect region: either by using supplied `opts.region` or by finding smallest
  bracketed region surrounding input position (cursor position by default).
  See |MiniSplitjoin.config.detect| for more details.

- Find separator positions using `separator` and `exclude_regions` from `opts`.
  Both brackets are treated as separators.
  See |MiniSplitjoin.config.detect| for more details.
  Note: stop if no separator positions are found.

- Modify separator positions to represent split positions. Last split position
  (which is inferred from right bracket) is moved one column to left so that
  right bracket would move on new line.

- Apply all hooks from `opts.split.hooks_pre`. Each is applied on the output of
  previous one. Input of first hook is split positions from previous step.
  Output of last one is used as split positions in next step.

- Split and update split positions with |MiniSplitjoin.split_at()|.

- Apply all hooks from `opts.split.hooks_post`. Each is applied on the output of
  previous one. Input of first hook is split positions from previous step plus
  region's right end (for easier hook code).
  Output of last one is used as function return value.

Note:
- By design, it doesn't detect if argument **should** be split, so application
  on arguments spanning multiple lines can lead to undesirable result.

Parameters ~
{opts} `(table|nil)` Options. Has structure from |MiniSplitjoin.config|
  inheriting its default values.

  Following extra optional fields are allowed:
  - <position> `(table)` - position at which to find smallest bracket region.
    See |MiniSplitjoin-glossary| for the structure.
    Default: cursor position.
  - <region> `(table)` - region at which to perform action. Assumes inclusive
    both start at left bracket and end at right bracket.
    See |MiniSplitjoin-glossary| for the structure.
    Default: `nil` to automatically detect region.

Return ~
`(any)` Output of last `opts.split.hooks_post` or `nil` if no split positions
  found. Default: return value of |MiniSplitjoin.split_at()| application.

------------------------------------------------------------------------------
                                                          *MiniSplitjoin.join()*
                          `MiniSplitjoin.join`({opts})
Join arguments

Overview:
- Detect region: either by using supplied `opts.region` or by finding smallest
  bracketed region surrounding input position (cursor position by default).
  See |MiniSplitjoin.config.detect| for more details.

- Compute join positions to be line ends of all but last region lines.
  Note: stop if no join positions are found.

- Apply all hooks from `opts.join.hooks_pre`. Each is applied on the output
  of previous one. Input of first hook is join positions from previous step.
  Output of last one is used as join positions in next step.

- Join and update join positions with |MiniSplitjoin.join_at()|.

- Apply all hooks from `opts.join.hooks_post`. Each is applied on the output
  of previous one. Input of first hook is join positions from previous step
  plus region's right end for easier hook code.
  Output of last one is used as function return value.

Parameters ~
{opts} `(table|nil)` Options. Has structure from |MiniSplitjoin.config|
  inheriting its default values.

  Following extra optional fields are allowed:
  - <position> `(table)` - position at which to find smallest bracket region.
    See |MiniSplitjoin-glossary| for the structure.
    Default: cursor position.
  - <region> `(table)` - region at which to perform action. Assumes inclusive
    both start at left bracket and end at right bracket.
    See |MiniSplitjoin-glossary| for the structure.
    Default: `nil` to automatically detect region.

Return ~
`(any)` Output of last `opts.split.hooks_post` or `nil` of no join positions
  found. Default: return value of |MiniSplitjoin.join_at()| application.

------------------------------------------------------------------------------
                                                        *MiniSplitjoin.gen_hook*
                            `MiniSplitjoin.gen_hook`
Generate common hooks

This is a table with function elements. Call to actually get hook.

All generated post-hooks return updated versions of their input reflecting
changes done inside hook.

Example for `lua` filetype (place it in 'lua.lua' filetype plugin, |ftplugin|): >lua

  local gen_hook = MiniSplitjoin.gen_hook
  local curly = { brackets = { '%b{}' } }

  -- Add trailing comma when splitting inside curly brackets
  local add_comma_curly = gen_hook.add_trailing_separator(curly)

  -- Delete trailing comma when joining inside curly brackets
  local del_comma_curly = gen_hook.del_trailing_separator(curly)

  -- Pad curly brackets with single space after join
  local pad_curly = gen_hook.pad_brackets(curly)

  -- Create buffer-local config
  vim.b.minisplitjoin_config = {
    split = { hooks_post = { add_comma_curly } },
    join  = { hooks_post = { del_comma_curly, pad_curly } },
  }
<
------------------------------------------------------------------------------
                                         *MiniSplitjoin.gen_hook.pad_brackets()*
                 `MiniSplitjoin.gen_hook.pad_brackets`({opts})
Generate hook to pad brackets

This is a join post-hook. Use in `join.hooks_post` of |MiniSplitjoin.config|.

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
   - <pad> `(string)` - pad to add after first and before last join positions.
     Default: `' '` (single space).
   - <brackets> `(table)` - array of bracket patterns indicating on which
     brackets action should be made. Has same structure as `brackets`
     in |MiniSplitjoin.config.detect|.
     Default: `MiniSplitjoin.config.detect.brackets`.

Return ~
`(function)` A hook which adds inner pad to first and last join positions and
  returns updated input join positions.

------------------------------------------------------------------------------
                               *MiniSplitjoin.gen_hook.add_trailing_separator()*
            `MiniSplitjoin.gen_hook.add_trailing_separator`({opts})
Generate hook to add trailing separator

This is a split post-hook. Use in `split.hooks_post` of |MiniSplitjoin.config|.

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
   - <sep> `(string)` - separator to add before last split position.
     Default: `','`.
   - <brackets> `(table)` - array of bracket patterns indicating on which
     brackets action should be made. Has same structure as `brackets`
     in |MiniSplitjoin.config.detect|.
     Default: `MiniSplitjoin.config.detect.brackets`.

Return ~
`(function)` A hook which adds separator before last split position and
  returns updated input split positions.

------------------------------------------------------------------------------
                               *MiniSplitjoin.gen_hook.del_trailing_separator()*
            `MiniSplitjoin.gen_hook.del_trailing_separator`({opts})
Generate hook to delete trailing separator

This is a join post-hook. Use in `join.hooks_post` of |MiniSplitjoin.config|.

Parameters ~
{opts} `(table|nil)` Options. Possible fields:
   - <sep> `(string)` - separator to remove before last join position.
     Default: `','`.
   - <brackets> `(table)` - array of bracket patterns indicating on which
     brackets action should be made. Has same structure as `brackets`
     in |MiniSplitjoin.config.detect|.
     Default: `MiniSplitjoin.config.detect.brackets`.

Return ~
`(function)` A hook which adds separator before last split position and
  returns updated input split positions.

------------------------------------------------------------------------------
                                                      *MiniSplitjoin.split_at()*
                     `MiniSplitjoin.split_at`({positions})
Split at positions

Overview:
- For each position move all characters after it to next line and make it have
  same indent as current one (see |MiniSplitjoin.get_indent_part()|).
  Also remove trailing whitespace at position line.

- Increase indent of inner lines by a single pad: tab in case of |noexpandtab|
  or |shiftwidth()| number of spaces otherwise.

Notes:
- Cursor is adjusted to follow text updates.
- Use output of this function to keep track of input positions.

Parameters ~
{positions} `(table)` Array of positions at which to perform split.
  See |MiniSplitjoin-glossary| for their structure. Note: they don't have
  to be ordered, but first and last ones will be used to infer lines for
  which indent will be increased.

Return ~
`(table)` Array of new positions to where input `positions` were moved.

------------------------------------------------------------------------------
                                                       *MiniSplitjoin.join_at()*
                      `MiniSplitjoin.join_at`({positions})
Join at positions

Overview:
- For each position join its line with the next line. Joining is done by
  replacing trailing whitespace of the line and indent of its next line
  (see |MiniSplitjoin.get_indent_part()|) with a pad string (single space except
  empty string for first and last positions). To adjust this, use hooks
  (for example, see |MiniSplitjoin.gen_hook.pad_brackets()|).

Notes:
- Cursor is adjusted to follow text updates.
- Use output of this function to keep track of input positions.

Parameters ~
{positions} `(table)` Array of positions at which to perform join.
  See |MiniSplitjoin-glossary| for their structure. Note: they don't have
  to be ordered, but first and last ones will have different pad string.

Return ~
`(table)` Array of new positions to where input `positions` were moved.

------------------------------------------------------------------------------
                                             *MiniSplitjoin.get_visual_region()*
                      `MiniSplitjoin.get_visual_region`()
Get previous visual region

Get previous visual selection using |`<| and |`>| marks in the format of
region (see |MiniSplitjoin-glossary|). Used in Visual mode mappings.

Note:
- Both marks are included in region, so for better
- In linewise Visual mode

Return ~
`(table)` A region. See |MiniSplitjoin-glossary| for exact structure.

------------------------------------------------------------------------------
                                               *MiniSplitjoin.get_indent_part()*
          `MiniSplitjoin.get_indent_part`({line}, {respect_comments})
Get string's indent part

Parameters ~
{line} `(string)` String for which to compute indent.
{respect_comments} `(boolean|nil)` Whether to respect comments as indent part.
  Default: `true`.

Return ~
`(string)` Part of input representing line's indent. Can be empty string.
  Use `string.len()` to compute indent in bytes.

------------------------------------------------------------------------------
                                                      *MiniSplitjoin.operator()*
                        `MiniSplitjoin.operator`({task})
Operator for Normal mode mappings

Main function to be used in expression mappings. No need to use it
directly, everything is setup in |MiniSplitjoin.setup()|.

Parameters ~
{task} `(string)` Name of task.


 vim:tw=78:ts=8:noet:ft=help:norl: