nvim-libmodal/doc/libmodal.txt

*libmodal.txt*             Create modes for Neovim
*libmodal*
*nvim-libmodal*

=============================================================================
0. Table of Contents                                           *libmodal-toc*

1. About ................ |libmodal-about|
2. Usage ................ |libmodal-usage|
3. Examples ............. |libmodal-examples|
4. Configuration ........ |libmodal-configuration|
5. License .............. |libmodal-license|
6. Bugs ................. |libmodal-bugs|
7. Contributing ......... |libmodal-contributing|
8. Changelog ............ |libmodal-changelog|
9. Credits .............. |libmodal-credits|

==============================================================================
1. About                                                      *libmodal-about*

|nvim-libmodal|:
- Author, Iron-E @ https://github.com/Iron-E & https://gitlab.com/Iron_E
- GitHub @ https://github.com/Iron-E/nvim-libmodal

Complete rewrite of |vim-libmodal|:
- Author, Iron-E @ https://github.com/Iron-E & https://gitlab.com/Iron_E
- GitHub @ https://github.com/Iron-E/vim-libmodal

|libmodal| is a Neovim library/|plugin| aimed at simplifying the creation
of new "modes" (e.g. |Insert|, |Normal|). The entrance of modes is
creator-defined, and their exit defaults to <Esc>. The use and name of
modes is also creator-defined, and is outlined in |libmodal-usage|.

See: |vim-modes|

Use Case ~
                                                   *libmodal-use-case-example*

As an |init.vim| configuration grows, it becomes harder to create keybindings
that alphabetically represent the action that they perform. To get around
this, |libmodal| allows users to create a new "layer" of keybindings contained
within a pseudo-|vim-mode|. This layer of keybindings can be bound to a
command which executes `libmodal.mode.enter()` or `libmodal.prompt.enter()`,
and any settings outside of these commands are preserved.

For example, say that a user of Neovim regularly converts between spaces and
tabs. They may define an "INDENT" mode that only requires pressing <Space>
or <Tab> to swap between 'expandtab' and 'shiftwidth' settings as well as
execute `retab`. This could be defined as a |user-function|, but the
keybindings are easier to remember as <Space> and <Tab>.

<Space> and <Tab>, however, are commonly mapped to. Rather than defining a
longer mapping to perform this operation, one may define a |user-command| to
enter "INDENT" mode where any mapping can be defined without affecting
mappings in other |vim-modes|.

Here is what that might look like:
>
	--[[ .config/lua/indent_mode.lua ]]

	local libmodal = require('libmodal')
	local indent_mode = {}

	local _combos = {
		-- tabs to spaces
		[' '] = 'set expandtab | %retab'
		-- spaces to tabs
		['	'] = 'set noexpandtab | %retab!'
	}

	function indent_mode.enter()
		libmodal.mode.enter('INDENT', _combos)
	end

	return indent_mode
<
>
	--[[  .config/nvim/init.vim ]]
	command! IndentModeEnter lua requre('indent_mode').enter()
	nnoremap <leader>i IndentModeEnter
<

Then this user could press `<leader>i` and have access to the <Space> and
<Tab> mappings that were defined, without affecting any other mappings.

See: |libmodal-usage|

==============================================================================
2. Usage                                                      *libmodal-usage*

The |libmodal| interface is designed completely in |Lua|. It is incompatable
with Vimscript until Neovim 0.5 releases (as `neovim/neovim#11306` will
merge). Because of this timed incompatability, the following must be done:

1. Define a |Lua| interface for your mode.
2. Use |lua-require| as a |user-command|.
	* See |lua-require-example| for information about how to do this.

`nvim-tabmode` is a plugin that was written to specifically display how to do
this. See below for a link to the repository where the source code may be
viewed.

The following is a reference for high-level functions meant to be used by mode
creators. For those who wish to see a low-level specification of |libmodal|,
see |libmodal-lua|.

Note: Examples for all topics covered here can be found in the "examples"
      folder at the root of the repository.

See: |api|, |lua-api|, https://github.com/Iron-E/nvim-tabmode

Functions ~

                                       *libmodal-mode* *libmodal.mode.enter()*
libmodal.mode.enter({name}, {instruction} [, {handleExit}])

	Enter a new |vim-mode| using {instruction} to determine what actions will
	be taken upon specific user inputs.

	User input is taken one character at a time using |getchar()|. It is
	passed through a |g:var| determined by the {name} of the mode. For
	example, if {name} is "FOO" then the |g:var| is `g:fooModeInput`.
	Additionally, this input is reported as a |char2nr| number, and as such
	should be decoded with `string.char()` (|nr2char| in |Lua|) if working
	with raw characters is desired.

	To take input on a line-by-line basis, see |libmodal-prompt|.

	Note: `libmodal.mode.enter()` may be called from inside itself. See
	      |libmodal-examples-submodes| for an example.

	Parameters: ~
		{name}         The name of the mode (e.g. |INSERT|).

			- Case-sensitive. Caps are recommended.

		{instruction}  What to do when accepting user input.

			- If {instruction} is a `table`, then it is treated as
			  a map of user key-chord to Vim |command|s. Example: >
			      local modeInstruction = {
			          ['zf'] = 'split',
			          ['zfo'] = 'vsplit',
			          ['zfc'] = 'tabnew'
			      }
<

			Note: If no `?` key is defined, one will be created
			      automatically.

			- If {instruction} is a `function`, then it is called
			  every time that |getchar()| completes. The user input
			  is received through `g:{name}ModeInput` (see above).

			Note: Some QoL features are available by default when
			      specifying a `table` value for {instruction} that
			      would otherwise have to be programmed manually if
			      a `function` is specified.

			      - A user's typed characters will show in the
			        lower right corner when {instruction} is a table.
			      - If `g:libmodalTimeouts` is enabled, then user input will be
			       subjected to the |timeoutlen|.

		{supressExit}  Whether or not to automatically exit the mode upon an
                       <Esc> press.

			- If `false`, then <Esc> is automatically mapped to
              exiting.
			- If `true`, then <Esc> is ignored unless specified by
			  the user. In such cases, the user should set the
			  `g:`{name}`ModeExit` variable to `true` when exiting is
			  desired. See |libmodal-examples-supress-exit|.

	See also: ~
		|lua-eval|                For type conversions between Vimscript to |Lua|.
		|libmodal-examples-mode|  For examples of this function.


                                   *libmodal-prompt* *libmodal.prompt.enter()*
libmodal.prompt.enter({name}, {instruction} [, {completions}])

	Besides accepting user input like keys in |Normal-mode|, |libmodal| is
	also capable of prompting the user for |input| like |Cmdline-mode|. To
	define a |Cmdline-mode|-like prompt, use this function rather than
	`libmodal.mode.enter()`.

	User input is taken using |input()|. It is passed through a |g:var|
	determined by the {name} of the mode. For example, if {name} is "FOO"
	then the |g:var| is `g:fooModeInput`.

	Parameters: ~
		{name}         The name of the mode (e.g. |INSERT|).

			- Case-sensitive. Caps are recommended.

		{instruction}  What to do when accepting user input.

			- If {instruction} is a `table`, then it is treated as
			  a map of user inputs to Vim |command|s. Example: >
		          local modeInstruction = {
		              ['new']   = 'tabnew',
		              ['close'] = 'tabclose',
		              ['last']  = 'tablast'
		          }
<
			- If {instruction} is a `function`, then it is called
			  every time that |input()| completes. The user input
			  is received through `g:{name}ModeInput` (see above).

			Note: If you want to create commands with arguments, you will
			      need to use a `function`.

		{completions}  An array-like `table` of commands that are offered by
		               the prompt.

			- Automatically generated when {instruction} is a `table`.
			- Used to provide auto-completion when the user is typing.
			- If unspecified, and {instruction} is not a `table`, then no
			  completions will be provided.

			Note: If no `help` command is defined, one will be created
			      automatically.

	See also: ~
		|lua-eval|                  For type conversions between Vimscript to |Lua|.
		|libmodal-examples-prompt|  For examples of this function.


==============================================================================
3. Examples                                                *libmodal-examples*

Below are examples written in |Lua| to help show how specific features of
|libmodal| may be implemented. In each example, the name of the mode is
defined as "FOO". Additionally, each category of example has one example for
both `function` and `table` {instruction}s.

The source code can be either copied from here or downloaded from the
repository's `examples/lua` folder. Assuming |libmodal| is installed, they can
all be tested using the |luafile| |command|.

See: |libmodal-usage|, |libmodal-use-case|, |lua-require-example|.

libmodal.mode.enter() ~
                                                      *libmodal-examples-mode*

Using a callback `function`: >
	local api = vim.api
	local libmodal = require('libmodal')
	local fooModeInputHistory = {}

	local function clearHistory(indexToCheck)
		if #fooModeInputHistory >= indexToCheck then
			fooModeInputHistory = {}
		end
	end

	function fooMode()
		fooModeInputHistory[#fooModeInputHistory + 1] = string.char(
			api.nvim_get_var('fooModeInput')
		)

		local index = 1
		if fooModeInputHistory[1] == 'z' then
			if fooModeInputHistory[2] == 'f' then
				if fooModeInputHistory[3] == 'o' then
					api.nvim_command("echom 'It works!'")
				else index = 3 end
			else index = 2 end
		end

		clearHistory(index)
	end

	libmodal.mode.enter('FOO', fooMode)
<

Using a |key-mapping| `table`: >
	local libmodal = require('libmodal')
	local fooModeCombos = {
		['zf'] = 'split',
		['zfo'] = 'vsplit',
		['zfc'] = 'tabnew'
	}

	libmodal.mode.enter('FOO', fooModeCombos)
<

                                              *libmodal-examples-supress-exit*

Using a callback `function`: >
	local libmodal = require('libmodal')

	function fooMode()
		local userInput = string.char(
			vim.api.nvim_get_var('fooModeInput')
		)

		if userInput == '' then
			vim.api.nvim_command("echom 'You cant leave using <Esc>.'")
		elseif userInput == 'q' then
			vim.api.nvim_set_var('fooModeExit', true)
		end
	end

	vim.api.nvim_set_var('fooModeExit', 0)
	libmodal.mode.enter('FOO', fooMode, true)
<

Using a |key-mapping| `table`: >
	local libmodal = require('libmodal')
	local fooModeCombos = {
		[''] = 'echom "You cant exit using escape."',
		['q'] = 'let g:fooModeExit = 1'
	}

	vim.api.nvim_set_var('fooModeExit', 0)
	libmodal.mode.enter('FOO', fooModeCombos, true)
<

                                                  *libmodal-examples-submodes*

Using a callback `function`: >
	local libmodal = require('libmodal')
	local fooModeRecurse = 0

	function fooMode()
		local userInput = string.char(vim.api.nvim_get_var(
			'foo' .. tostring(fooModeRecurse) .. 'ModeInput'
		))

		if userInput == 'z' then
			fooModeRecurse = fooModeRecurse + 1
			enter()
			fooModeRecurse = fooModeRecurse - 1
		end
	end

	function enter()
		libmodal.mode.enter('FOO' .. fooModeRecurse, fooMode)
	end

	enter()
<

Using a |key-mapping| `table`: >
	local libmodal = require('libmodal')
	local fooModeRecurse = 0
	local fooModeCombos = {
		['z'] = 'lua fooMode()'
	}

	function fooMode()
		fooModeRecurse = fooModeRecurse + 1
		libmodal.mode.enter('FOO' .. fooModeRecurse, fooModeCombos)
		fooModeRecurse = fooModeRecurse - 1
	end

	fooMode()
<


libmodal.prompt.enter() ~
                                                    *libmodal-examples-prompt*

Using a callback `function`: >
	local libmodal = require('libmodal')
	local api = vim.api
	local commandList = {'new', 'close', 'last'}

	function fooMode()
		local userInput = vim.api.nvim_get_var('fooModeInput')
		if userInput == 'new' then
			api.nvim_command('tabnew')
		elseif userInput == 'close' then
			api.nvim_command('tabclose')
		elseif userInput == 'last' then
			api.nvim_command('tablast')
		end
	end

	libmodal.prompt.enter('FOO', fooMode, commandList)
<

Using a |command| `table`: >
	local libmodal = require('libmodal')
	local commands = {
		['new']   = 'tabnew',
		['close'] = 'tabclose',
		['last']  = 'tablast'
	}

	libmodal.prompt.enter('BAR', commands)
<

==============================================================================
4. Configuration                                      *libmodal-configuration*

Highlighting ~
                                                   *libmodal-highlight-groups*


The following |highlight-groups| can be |config|ured to change a mode's |color|s:

Name              Default      Description
----              -------      -----------
`LibmodalPrompt`  `ModeMsg`    Color for the mode text.
`LibmodalStar`    `StatusLine` Color for the prompt text.

Note: `LibmodalStar`'s name — while not indicative of its use — is used for
      the sake of backwards compatability.
	  - While |nvim-libmodal| might not be 100% backwards compatable with
		|vim-libmodal| due to limitations of Neovim 0.4, an update will ship
		when Neovim 0.5 launches that will introduce interoperaability between
		the two.

Timeouts ~
                                                           *libmodal-timeouts*
                                                          *g:libmodalTimeouts*

When `libmodal.mode.enter()`'s {instruction} argument is a `table`, mode
creators may also enable the use of Vim's built-in 'timeout' feature.

To enable 'timeout's, one may set the following |variables|:
>
	" Set libmodal modes to turn timeouts on.
	let g:libmodalTimeouts = 1
	" Enable timeouts for specific mode.
	let g:{name}ModeTimeout = 1
<
Similarly, to disable them, one may set them to `0`.

When `g:libmodalTimeouts` or `g:{name}ModeTimeout` is set to `1`, |libmodal|
will automatically execute commands that have mappings that might also be
longer mappings. For example:
	If a mode specifies `zf` and `zfo` as mappings,
	- Turning 'timeout's on will cause `zf` to be executed if the user waits
	  for 'timeoutlen' without typing another character.
	- If 'timeout' were to be off in this case, then the user would either
	  have to hit <CR> to execute `zf` or hit `o` to execute `zfo`.

NOTE: `g:libmodalTimeouts` defaults to the 'timeout' value.

NOTE: The `g:limbodalTimeouts` variable should NOT be defined by plugins.
      - Allow users to decide whether or not they want timeouts to be
        enabled globally themselves.

NOTE: Mode-specific timeout variables will override `g:libmodalTimeouts`.

When enabled, |libmodal-timeouts| will reference the mode user's 'timeoutlen'
as specified in their |config|. This way, modes will feel consistent to users
by default.

However, mode creators may change 'timeoutlen' upon entrance of a mode, and
then reset it upon exit. Example:

	Vimscript: ~
>
		function! s:FooMode() abort
			" Get the user's preferred timeout length.
			let l:timeoutlen = &timeoutlen
			" Set it to something else, like 1500ms
			let &timeoutlen = 1500
			" Enter a mode
			call libmodal#Enter(…)
			" Reset the timeout
			let &timeoutlen = l:timeoutlen
		endfunction
<
	Lua: ~
>
		local api = vim.api
		local libmodal = require('libmodal')

		function fooMode()
			-- Get the user's preferred timeout length.
			local prevTimeoutLen = api.nvim_get_option('timeoutlen')
			-- Set it to something else, like 1500ms.
			api.nvim_set_option('timeoutlen', 1500)
			-- Enter a mode.
			libmodal.mode.enter(…)
			-- Restore the `timeoutlen`
			api.nvim_set_option('timeoutlen', prevTimeoutLen)
		end
<

Mode creators who use `function` {instruction}s may define timeouts manually
using |timers|, which is how |libmodal| implements them internally.

==============================================================================
5. License                                                  *libmodal-license*

`nvim-libmodal` – Create new "modes" for Neovim.
Copyright © 2020 Iron-E

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

==============================================================================
6. Bugs                                                        *libmodal-bugs*

* Passing a |funcref| through Vimscript to |Lua| yields a `nil`.
	* This bug is fixed in Neovim 0.5, and when it releases, there will be a
	  patch for this plugin to fix it and introduce compatability with
	  |vim-libmodal|.

==============================================================================
7. Contributing                                        *libmodal-contributing*

Code ~

	Bugfixes ~

	If you discover a bug and believe you know the solution to fixing it, then
	submit a bug report and state that you are working on a fix (and what that
	fix might be), and what general timeframe the fix may be completed in
	(months, weeks, days, etc.).

	When the fix is complete, submit a PR that references the issue you
	submitted.

	Features ~

	If there is a feature you would like to be a part of |libmodal|, the best
	thing you can do is submit a feature request, and then state that you are
	working on a pull request (PR) so others don't attempt to do the same work
	at the same time.

	When you believe your feature is complete, write some examples for it in
	the `examples/lua` folder, and add them to |libmodal-examples| as
	appropriate.

	Assure that all existing |libmodal-examples| continue to work with your
	feature, unless a breaking change was discussed on the feature request.
	If you need help getting them to pass, you can ask for help on the PR.

	Reference the issue you submitted on the PR so that the two show up
	together when looking back at the history.

	Contributing documentation is not necessary but appreciated, since the
	person who knows the most about the feature being implemented is most
	likely the one implementing it.

Documentation ~

If there is a problem with the documentation, or you see an area where it
could be improved, don't hesitate to submit an issue and a PR. At the very
least it will exist in history if such an issue comes up again, and likely it
will serve to help yourself and others with more clear and concise wording, or
with more helpful and practical examples.

Issues ~

Issues are greatly welcomed on the GitHub repository, whether they are bug
reports, feature requests, documentation improvements, or misunderstandings:
it's all good to have in the archive.

When submitting an issue, please describe the following:

1. Context regarding the issue (how you discovered it, pertinent information,
   etc.)
2. Detailed description of the issue.
3. Steps to reproduce (if applicable).
4. Expected behavior (if applicable).
5. Attached media (screenshots, logs, etc.) (if applicable).

==============================================================================
8. Changelog                                              *libmodal-changelog*

0.3.0 ~

* Generate `?` mapping for |libmodal-mode|s.

0.2.1 ~

* Fix `help` command completion being shown during an {instruction} callback
  `function` when none should be shown.

0.2.0 ~

* |libmodal-prompt| implemetation from |vim-libmodal|.
* |libmodal-prompt|s now automatically generate `help` command if none is
  provided.

0.1.0 ~

* |libmodal-mode| implementation from |vim-libmodal|.

==============================================================================
9. Credits                                                  *libmodal-credits*

Credit                      Reason
---------------------       ----------------------------------
Daniel Steinberg            |vim-win| creator and inspiration.
Iron-E                      Primary contibuter/maintainer.
neoclide/|coc-nvim|           Development environment provider.
r/Neovim                    |Lua| and Neovim reference.
Roberto Ierusalimschy       "Programming In Lua: 5.1".
Steve Losh                  "Learn Vimscript The Hard Way".
tbastos/vim-lua             Syntax highlighting for |Lua|.
u/Mambu38                   |Lua| reference.
u/oryiesis                  Inspiration.
www.lua-users.org           |Lua| reference.
www.stackoverflow.com       Vimscript and |Lua| reference.

==============================================================================
 vim:tw=78:ts=4:ft=help:norl: