diff --git a/README.md b/README.md
index 7ecf73a..bd47ed6 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,8 @@ This is meant to be used as a **library**, not a plugin. On its own, `u.nvim` do
## Features
+- **Rendering System**: a utility that can declaratively render NeoVim-specific hyperscript into a buffer, supporting creating/managine extmarks, highlights, and key-event handling (requires NeoVim >0.11)
+- **Signals**: a simple dependency tracking system that pairs well with the rendering utilities for creating reactive/interactive UIs in NeoVim.
- **Range Utility**: Get context-aware selections with ease. Replace regions with new text. Think of it as a programmatic way to work with visual selections (or regions of text).
- **Code Writer**: Write code with automatic indentation and formatting.
- **Operator Key Mapping**: Flexible key mapping that works with the selected text.
@@ -20,7 +22,108 @@ lazy.nvim:
{ 'jrop/u.nvim', lazy = true }
```
-## Usage
+## Signal and Rendering Usage
+
+### Overview
+
+The Signal and Rendering mechanisms are two subsystems of u.nvim, that, while
+simplistic, compose together powerfully to create a system for interactive and
+responsive user interfaces. Here is a quick example that show-cases how easy it
+is to dive in to make any buffer an interactive UI:
+
+<details>
+<summary>Example Code: counter.lua</summary>
+
+```lua
+local tracker = require 'u.tracker'
+local Buffer = require 'u.buffer'
+local h = require('u.renderer').h
+
+-- Create an buffer for the UI
+vim.cmd.vnew()
+local ui_buf = Buffer.current()
+ui_buf:set_tmp_options()
+
+local s_count = tracker.create_signal(0)
+
+-- Effect: Render
+-- Setup the effect for rendering the UI whenever dependencies are updated
+tracker.create_effect(function()
+ -- Calling `Signal:get()` in an effect registers the given signal as a
+ -- dependency of the current effect. Whenever that signal (or any other
+ -- dependency) changes, the effect will rerun. In this particular case,
+ -- rendering the UI is an effect that depends on one signal.
+ local count = s_count:get()
+
+ -- Markup is hyperscript, which is just 1) text, and 2) tags (i.e.,
+ -- constructed with `h(...)` calls). To help organize the markup, text and
+ -- tags can be nested in tables at any depth. Line breaks must be specified
+ -- manually, with '\n'.
+ ui_buf:render {
+ 'Reactive Counter Example\n',
+ '========================\n\n',
+
+ { 'Counter: ', tostring(count), '\n' },
+
+ '\n',
+
+ {
+ h('text', {
+ hl = 'DiffDelete',
+ on_key = {
+ ['\r'] = function()
+ -- Update the contents of the s_count signal, notifying any
+ -- dependencies (in this case, the render effect):
+ s_count:update(function(n) return n - 1 end)
+ -- Also equivalent: s_count:set(s_count:get() - 1)
+ return ''
+ end,
+ },
+ }, ' Decrement '),
+ ' ',
+ h('text', {
+ hl = 'DiffAdd',
+ on_key = {
+ ['\r'] = function()
+ -- Update the contents of the s_count signal, notifying any
+ -- dependencies (in this case, the render effect):
+ s_count:update(function(n) return n + 1 end)
+ -- Also equivalent: s_count:set(s_count:get() + 1)
+ return ''
+ end,
+ },
+ }, ' Increment '),
+ },
+
+ '\n',
+ '\n',
+ { 'Press <CR> on each "button" above to increment/decrement the counter.' },
+ }
+end)
+```
+
+</details>
+
+#### Explanation of Components
+
+- **Signal (`s_count`)**: This is the main reactive variable that holds the
+ current count value. Updating this signal triggers the rendering effect.
+- **Effect**: This function will re-render the UI whenever `s_count` changes.
+ The effect accesses the signal value and updates the UI.
+- **Hyperscript Markup**: The UI is defined using tags generated by `h(...)`.
+ You can specify interactions via `on_key`, allowing for responsive user
+ events.
+- **Key Events**: The `on_key` functions will update the signal’s value, thus
+ notifying the rendering effect to re-run and reflect the changes in the UI.
+
+### Conclusion
+
+By combining the `u.tracker` signal system with the rendering capabilities of
+**u.nvim**, you can create interactive UI components that respond to user
+inputs dynamically. This pattern can be extended to implement more complex UI
+interactions in your NeoVim plugins.
+
+## Range Usage
### A note on indices
@@ -136,7 +239,8 @@ cw:write('}')
#### Custom Text Objects
-Simply by returning a `Range` or a `Pos`, you can easily and quickly define your own text objects:
+Simply by returning a `Range` or a `Pos`, you can easily and quickly define
+your own text objects:
```lua
local utils = require 'u.utils'
diff --git a/examples/counter.lua b/examples/counter.lua
new file mode 100644
index 0000000..952a5f3
--- /dev/null
+++ b/examples/counter.lua
@@ -0,0 +1,65 @@
+local tracker = require 'u.tracker'
+local Buffer = require 'u.buffer'
+local h = require('u.renderer').h
+
+-- Create an buffer for the UI
+vim.cmd.vnew()
+local ui_buf = Buffer.current()
+ui_buf:set_tmp_options()
+
+local s_count = tracker.create_signal(0, 'counter_signal')
+
+-- Effect: Render
+-- Setup the effect for rendering the UI whenever dependencies are updated
+tracker.create_effect(function()
+ -- Calling `Signal:get()` in an effect registers the given signal as a
+ -- dependency of the current effect. Whenever that signal (or any other
+ -- dependency) changes, the effect will rerun. In this particular case,
+ -- rendering the UI is an effect that depends on one signal.
+ local count = s_count:get()
+
+ -- Markup is hyperscript, which is just 1) text, and 2) tags (i.e.,
+ -- constructed with `h(...)` calls). To help organize the markup, text and
+ -- tags can be nested in tables at any depth. Line breaks must be specified
+ -- manually, with '\n'.
+ ui_buf:render {
+ 'Reactive Counter Example\n',
+ '========================\n\n',
+
+ { 'Counter: ', tostring(count), '\n' },
+
+ '\n',
+
+ {
+ h('text', {
+ hl = 'DiffDelete',
+ on_key = {
+ ['\r'] = function()
+ -- Update the contents of the s_count signal, notifying any
+ -- dependencies (in this case, the render effect):
+ s_count:update(function(n) return n - 1 end)
+ -- Also equivalent: s_count:set(s_count:get() - 1)
+ return ''
+ end,
+ },
+ }, ' Decrement '),
+ ' ',
+ h('text', {
+ hl = 'DiffAdd',
+ on_key = {
+ ['\r'] = function()
+ -- Update the contents of the s_count signal, notifying any
+ -- dependencies (in this case, the render effect):
+ s_count:update(function(n) return n + 1 end)
+ -- Also equivalent: s_count:set(s_count:get() + 1)
+ return ''
+ end,
+ },
+ }, ' Increment '),
+ },
+
+ '\n',
+ '\n',
+ { 'Press <CR> on each "button" above to increment/decrement the counter.' },
+ }
+end)
diff --git a/examples/picker.lua b/examples/picker.lua
new file mode 100644
index 0000000..0dda21f
--- /dev/null
+++ b/examples/picker.lua
@@ -0,0 +1,881 @@
+local utils = require 'u.utils'
+local Buffer = require 'u.buffer'
+local Renderer = require('u.renderer').Renderer
+local h = require('u.renderer').h
+local TreeBuilder = require('u.renderer').TreeBuilder
+local tracker = require 'u.tracker'
+
+local M = {}
+
+local S_EDITOR_DIMENSIONS = tracker.create_signal(utils.get_editor_dimensions(), 's:editor_dimensions')
+vim.api.nvim_create_autocmd('VimResized', {
+ callback = function()
+ local new_dim = utils.get_editor_dimensions()
+ S_EDITOR_DIMENSIONS:set(new_dim)
+ end,
+})
+
+--- @param low number
+---@param x number
+---@param high number
+local function clamp(low, x, high)
+ x = math.max(low, x)
+ x = math.min(x, high)
+ return x
+end
+
+--- @generic T
+--- @param arr `T`[]
+--- @return T[]
+local function shallow_copy_arr(arr) return vim.iter(arr):totable() end
+
+--------------------------------------------------------------------------------
+-- BEGIN create_picker
+--
+-- This is the star of the show (in this file, anyway).
+-- In summary, the outline of this function is:
+-- 1. Setup signals/memos for computing the picker size, and window positions
+-- 2. Create the two windows:
+-- a. The picker input. This is where the filter is typed
+-- b. The picker list. This is where the items are displayed
+-- 3. Setup event handlers that respond to user input
+-- 4. Render the list. After all the prework above, this is probably the
+-- shortest portion of this function.
+--------------------------------------------------------------------------------
+
+--- @alias SelectController {
+--- get_items: fun(): T[];
+--- set_items: fun(items: T[]);
+--- set_filter_text: fun(filter_text: string);
+--- get_selected_indices: fun(): number[];
+--- get_selected_items: fun(): T[];
+--- set_selected_indices: fun(indicies: number[], ephemeral?: boolean);
+--- close: fun();
+--- }
+--- @alias SelectOpts<T> {
+--- items: `T`[];
+--- multi?: boolean;
+--- format_item?: fun(item: T[]): Tree;
+--- on_finish?: fun(items: T[], indicies: number[]);
+--- on_selection_changed?: fun(items: T[], indicies: number[]);
+--- mappings?: table<string, fun(select: SelectController)>;
+--- }
+
+--- @generic T
+--- @param opts SelectOpts<T>
+function M.create_picker(opts)
+ local is_in_insert_mode = vim.api.nvim_get_mode().mode:sub(1, 1) == 'i'
+ local stopinsert = not is_in_insert_mode
+
+ if opts.multi == nil then opts.multi = false end
+
+ local H = {}
+
+ --- Runs a function `fn`, and if it fails, cleans up the UI by calling
+ --- `H.finish`
+ ---
+ --- @generic T
+ --- @param fn fun(): `T`
+ --- @return T
+ local function safe_run(fn, ...)
+ local ok, result_or_error = pcall(fn, ...)
+ if not ok then
+ pcall(H.finish, true, result_or_error)
+ error(result_or_error .. '\n' .. debug.traceback())
+ end
+ return result_or_error
+ end
+
+ --- Creates a function that safely calls the given function, cleaning up the
+ --- UI if it ever fails
+ ---
+ --- @generic T
+ --- @param fn `T`
+ --- @return T
+ local function safe_wrap(fn)
+ return function(...) return safe_run(fn, ...) end
+ end
+
+ --
+ -- Compute the positions of the input bar and the list:
+ --
+
+ -- Reactively compute the space available for the picker based on the size of
+ -- the editor
+ local s_editor_dimensions = S_EDITOR_DIMENSIONS:clone()
+ local s_picker_space_available = tracker.create_memo(safe_wrap(function()
+ local editor_dim = s_editor_dimensions:get()
+ local width = math.floor(editor_dim.width * 0.75)
+ local height = math.floor(editor_dim.height * 0.75)
+ local row = math.floor((editor_dim.height - height) / 2)
+ local col = math.floor((editor_dim.width - width) / 2)
+ return { width = width, height = height, row = row, col = col }
+ end))
+
+ -- Reactively compute the size of the prompt (input) bar
+ local s_w_input_coords = tracker.create_memo(safe_wrap(function()
+ local picker_coords = s_picker_space_available:get()
+ return {
+ width = picker_coords.width,
+ height = 1,
+ row = picker_coords.row,
+ col = picker_coords.col,
+ }
+ end))
+
+ -- Reactively compute the size of the list view
+ local s_w_list_coords = tracker.create_memo(safe_wrap(function()
+ local picker_coords = s_picker_space_available:get()
+ return {
+ width = picker_coords.width,
+ height = picker_coords.height - 3,
+ row = picker_coords.row + 3,
+ col = picker_coords.col,
+ }
+ end))
+
+ --
+ -- Create resources (i.e., windows):
+ --
+
+ local w_input_cfg = {
+ width = s_w_input_coords:get().width,
+ height = s_w_input_coords:get().height,
+ row = s_w_input_coords:get().row,
+ col = s_w_input_coords:get().col,
+ relative = 'editor',
+ focusable = true,
+ border = 'rounded',
+ }
+ local w_input_buf = Buffer.create(false, true)
+ local w_input = vim.api.nvim_open_win(w_input_buf.buf, false, w_input_cfg)
+ vim.wo[w_input].number = false
+ vim.wo[w_input].relativenumber = false
+
+ -- The following option is a signal to other plugins like 'cmp' to not mess
+ -- with this buffer:
+ vim.bo[w_input_buf.buf].buftype = 'prompt'
+ vim.fn.prompt_setprompt(w_input_buf.buf, '')
+
+ vim.api.nvim_set_current_win(w_input)
+ tracker.create_effect(safe_wrap(function()
+ -- update window position/size every time the editor is resized:
+ w_input_cfg = vim.tbl_deep_extend('force', w_input_cfg, s_w_input_coords:get())
+ vim.api.nvim_win_set_config(w_input, w_input_cfg)
+ end))
+
+ local w_list_cfg = {
+ width = s_w_list_coords:get().width,
+ height = s_w_list_coords:get().height,
+ row = s_w_list_coords:get().row,
+ col = s_w_list_coords:get().col,
+ relative = 'editor',
+ focusable = true,
+ border = 'rounded',
+ }
+ local w_list_buf = Buffer.create(false, true)
+ local w_list = vim.api.nvim_open_win(w_list_buf.buf, false, w_list_cfg)
+ vim.wo[w_list].number = false
+ vim.wo[w_list].relativenumber = false
+ vim.wo[w_list].scrolloff = 0
+ tracker.create_effect(safe_wrap(function()
+ -- update window position/size every time the editor is resized:
+ w_list_cfg = vim.tbl_deep_extend('force', w_list_cfg, s_w_list_coords:get())
+ vim.api.nvim_win_set_config(w_list, w_list_cfg)
+ end))
+
+ -- Now that we have created the window with the prompt in it, start insert
+ -- mode so that the user can type immediately:
+ vim.cmd.startinsert()
+
+ --
+ -- State:
+ --
+
+ local s_items_raw = tracker.create_signal(opts.items, 's:items')
+ local s_items = s_items_raw:debounce(100)
+ local s_selected_indices = tracker.create_signal({}, 's:selected_indices')
+ local s_top_offset = tracker.create_signal(0, 's:top_offset')
+ local s_cursor_index = tracker.create_signal(1, 's:cursor_index')
+
+ local s_filter_text_undebounced = tracker.create_signal('', 's:filter_text')
+ w_input_buf:autocmd('TextChangedI', {
+ callback = safe_wrap(function() s_filter_text_undebounced:set(vim.api.nvim_get_current_line()) end),
+ })
+ local s_filter_text = s_filter_text_undebounced:debounce(50)
+
+ --
+ -- Derived State:
+ --
+
+ local s_formatted_items = tracker.create_memo(function()
+ local function _format_item(item) return opts.format_item and opts.format_item(item) or tostring(item) end
+
+ local items = s_items:get()
+ return vim.iter(items):map(function(item) return { item = item, formatted = _format_item(item) } end):totable()
+ end)
+
+ -- When the filter text changes, update the filtered items:
+ local s_filtered_items = tracker.create_memo(
+ safe_wrap(function()
+ local formatted_items = s_formatted_items:get()
+ local filter_text = vim.trim(s_filter_text:get())
+ local filter_pattern = (#formatted_items > 250 and #filter_text <= 3) and (filter_text:gsub('%.', '%%.'))
+ or vim.iter(vim.split(filter_text, '')):map(function(c) return c .. '.*' end):join ''
+
+ local new_filtered_items = vim
+ .iter(formatted_items)
+ :enumerate()
+ :map(function(i, inf) return { orig_idx = i, item = inf.item, formatted = inf.formatted } end)
+ :filter(function(inf)
+ if filter_text == '' then return true end
+ local formatted_as_string = Renderer.markup_to_string { tree = inf.formatted }
+ local match = string.match(Renderer.markup_to_string { tree = formatted_as_string }, filter_pattern)
+ return match ~= nil
+ end)
+ :totable()
+
+ -- Don't do the levenshtein-sort if there are over 250 items:
+ if #new_filtered_items <= 250 then
+ table.sort(new_filtered_items, function(a_inf, b_inf)
+ local a = Renderer.markup_to_string { markup = a_inf.formatted }
+ local b = Renderer.markup_to_string { markup = b_inf.formatted }
+ if a == b then return false end
+
+ local lev_a = utils.levenshtein(vim.split(filter_text, ''), vim.split(a, ''))
+ local lev_b = utils.levenshtein(vim.split(filter_text, ''), vim.split(b, ''))
+ return #lev_a < #lev_b
+ end)
+ end
+
+ s_top_offset:set(0)
+ s_cursor_index:set(1)
+ return new_filtered_items
+ end),
+ 'e:(filter_text=>filtered_items)'
+ )
+
+ -- Visible items, are _just_ the items that fit into the current viewport.
+ -- This is an optimization so that we are not rendering thousands of lines of
+ -- items on each state-change.
+ local s_visible_items = tracker.create_memo(
+ safe_wrap(function()
+ return vim
+ .iter(s_filtered_items:get())
+ :enumerate()
+ :skip(s_top_offset:get())
+ :take(s_w_list_coords:get().height)
+ :map(
+ function(i, inf)
+ return {
+ filtered_idx = i,
+ orig_idx = inf.orig_idx,
+ item = inf.item,
+ formatted = inf.formatted,
+ }
+ end
+ )
+ :totable()
+ end),
+ 'm:visible_items'
+ )
+
+ -- Track selection information:
+ local s_selection_info = tracker.create_memo(
+ safe_wrap(function()
+ local items = s_items:get()
+ local selected_indices = s_selected_indices:get()
+ --- @type { orig_idx: number; item: T }[]
+ local filtered_items = s_filtered_items:get()
+ local cursor_index = s_cursor_index:get()
+ local indices = shallow_copy_arr(selected_indices) -- shallow copy
+ if #indices == 0 and #filtered_items > 0 then indices = { filtered_items[cursor_index].orig_idx } end
+ return {
+ items = vim.iter(indices):map(function(i) return items[i] end):totable(),
+ indices = indices,
+ }
+ end),
+ 'm:selection_info'
+ )
+
+ --- When it is time to close the picker, this is the main cleanup routine
+ --- that runs in all cases:
+ ---
+ --- @param esc? boolean Whether the user pressed <Esc> or not
+ --- @param err? any Any error that occurred
+ function H.finish(esc, err)
+ -- s_editor_dimensions is the only signal that is cloned from a global,
+ -- one. It is therefore the only one that needs to be manually disposed.
+ -- The other ones should get cleaned up by the GC
+ s_editor_dimensions:dispose()
+ -- If we happen to have any async state-changes coming down the pipeline,
+ -- we can say right now that we are done rendering new UI (to avoid
+ -- "invalid window ID" errors):
+ H.unsubscribe_render_effect()
+ -- buftype=prompt buffers are not "temporary", so delete the buffer manually:
+ vim.api.nvim_buf_delete(w_input_buf.buf, { force = true })
+ -- The following is not needed, since the buffer is deleted above:
+ -- vim.api.nvim_win_close(w_input, false)
+ vim.api.nvim_win_close(w_list, false)
+ if stopinsert then vim.cmd.stopinsert() end
+ local inf = s_selection_info:get()
+ if not err and opts.on_finish then
+ -- If on_finish opens another picker, the closing of this one can happen
+ -- in _too_ quick succession, so put a small delay in there.
+ --
+ -- TODO: figure out _why_ this is actually happening, and then a better
+ -- way to handle this.
+ vim.defer_fn(function()
+ if esc then
+ opts.on_finish({}, {})
+ else
+ opts.on_finish(inf.items, inf.indices)
+ end
+ end, 100)
+ end
+ end
+
+ -- On selection info changed:
+ tracker.create_effect(
+ safe_wrap(function()
+ local inf = s_selection_info:get()
+ if opts.on_selection_changed then opts.on_selection_changed(inf.items, inf.indices) end
+ end),
+ 'e:selection_changed'
+ )
+
+ --
+ -- Public API (i.e., `controller`):
+ -- We will fill in the methods further down, but we need this variable in scope so that it can be
+ -- closed over by some of the event handlers:
+ --
+ local controller = {}
+
+ --
+ -- Events
+ --
+ vim.keymap.set('i', '<Esc>', function() H.finish(true) end, { buffer = w_input_buf.buf })
+
+ vim.keymap.set('i', '<CR>', function() H.finish() end, { buffer = w_input_buf.buf })
+
+ local function action_next_line()
+ local max_line = #s_filtered_items:get()
+ local next_cursor_index = clamp(1, s_cursor_index:get() + 1, max_line)
+ if next_cursor_index - s_top_offset:get() > s_w_list_coords:get().height then
+ s_top_offset:set(s_top_offset:get() + 1)
+ end
+ s_cursor_index:set(next_cursor_index)
+ end
+ vim.keymap.set('i', '<C-n>', safe_wrap(action_next_line), { buffer = w_input_buf.buf, desc = 'Picker: next' })
+
+ vim.keymap.set(
+ 'i',
+ '<C-p>',
+ safe_wrap(function()
+ local max_line = #s_filtered_items:get()
+ local next_cursor_index = clamp(1, s_cursor_index:get() - 1, max_line)
+ if next_cursor_index - s_top_offset:get() < 1 then s_top_offset:set(s_top_offset:get() - 1) end
+ s_cursor_index:set(next_cursor_index)
+ end),
+ { buffer = w_input_buf.buf, desc = 'Picker: previous' }
+ )
+
+ vim.keymap.set(
+ 'i',
+ '<Tab>',
+ safe_wrap(function()
+ if not opts.multi then return end
+
+ local index = s_filtered_items:get()[s_cursor_index:get()].orig_idx
+ if vim.tbl_contains(s_selected_indices:get(), index) then
+ s_selected_indices:set(vim.iter(s_selected_indices:get()):filter(function(i) return i ~= index end):totable())
+ else
+ local new_selected_indices = shallow_copy_arr(s_selected_indices:get())
+ table.insert(new_selected_indices, index)
+ s_selected_indices:set(new_selected_indices)
+ end
+ action_next_line()
+ end),
+ { buffer = w_input_buf.buf }
+ )
+
+ for key, fn in pairs(opts.mappings or {}) do
+ vim.keymap.set('i', key, safe_wrap(function() return fn(controller) end), { buffer = w_input_buf.buf })
+ end
+
+ -- Render:
+ H.unsubscribe_render_effect = tracker.create_effect(
+ safe_wrap(function()
+ local selected_indices = s_selected_indices:get()
+ local top_offset = s_top_offset:get()
+ local cursor_index = s_cursor_index:get()
+ --- @type { filtered_idx: number; orig_idx: number; item: T; formatted: string }[]
+ local visible_items = s_visible_items:get()
+
+ -- The above has to run in the execution context for the signaling to work, but
+ -- the following cannot run in a NeoVim loop-callback:
+ vim.schedule(function()
+ w_list_buf:render(TreeBuilder.new()
+ :nest(function(tb)
+ for loop_idx, inf in ipairs(visible_items) do
+ local is_cur_line = inf.filtered_idx == cursor_index
+ local is_selected = vim.tbl_contains(selected_indices, inf.orig_idx)
+
+ tb:put(loop_idx > 1 and '\n')
+ tb:put(is_cur_line and h('text', { hl = 'Structure' }, '❯') or ' ')
+ tb:put(is_selected and h('text', { hl = 'Comment' }, '* ') or ' ')
+ tb:put(inf.formatted)
+ end
+ end)
+ :tree())
+
+ -- set the window viewport to have the first line in view:
+ pcall(vim.api.nvim_win_call, w_list, function() vim.fn.winrestview { topline = 1 } end)
+ pcall(vim.api.nvim_win_set_cursor, w_list, { cursor_index - top_offset, 0 })
+ end)
+ end),
+ 'e:render'
+ )
+
+ --
+ -- Populate the public API:
+ --
+ function controller.get_items()
+ return safe_run(function() return s_items_raw:get() end)
+ end
+
+ ---@param items T[]
+ function controller.set_items(items)
+ return safe_run(function() s_items_raw:set(items) end)
+ end
+
+ function controller.set_filter_text(filter_text)
+ return safe_run(function()
+ vim.api.nvim_win_call(w_input, function() vim.api.nvim_set_current_line(filter_text) end)
+ end)
+ end
+
+ function controller.get_selected_indices()
+ return safe_run(function() return s_selection_info:get().indices end)
+ end
+
+ function controller.get_selected_items()
+ return safe_run(function() return s_selection_info:get().items end)
+ end
+
+ --- @param indicies number[]
+ ---@param ephemeral? boolean
+ function controller.set_selected_indices(indicies, ephemeral)
+ return safe_run(function()
+ if ephemeral == nil then ephemeral = false end
+
+ if ephemeral and #indicies == 1 then
+ local matching_filtered_item_idx, _ = vim
+ .iter(s_filtered_items:get())
+ :enumerate()
+ :find(function(_idx, inf) return inf.orig_idx == indicies[1] end)
+ if matching_filtered_item_idx ~= nil then s_cursor_index:set(indicies[1]) end
+ else
+ if not opts.multi then
+ local err = 'Cannot set multiple selected indices on a single-select picker'
+ H.finish(true, err)
+ error(err)
+ end
+ s_selected_indices:set(indicies)
+ end
+ end)
+ end
+
+ function controller.close()
+ return safe_run(function() H.finish(true) end)
+ end
+
+ return controller --[[@as SelectController]]
+end
+
+--------------------------------------------------------------------------------
+-- END create_picker
+--------------------------------------------------------------------------------
+
+--------------------------------------------------------------------------------
+-- vim.ui.select override
+--------------------------------------------------------------------------------
+
+local ORIGINAL_UI_SELECT
+function M.register_ui_select()
+ ORIGINAL_UI_SELECT = vim.ui.select
+ --- @generic T
+ --- @param items `T`[]
+ --- @param opts { prompt?: string, kind?: any, format_item?: fun(item: T):string }
+ --- @param cb fun(item: T|nil):any
+ function vim.ui.select(items, opts, cb)
+ M.create_picker {
+ items = items,
+ format_item = function(item)
+ local s = opts.format_item and opts.format_item(item) or tostring(item)
+ s = s:gsub('<', '<')
+ return s
+ end,
+ on_finish = function(sel_items)
+ if #sel_items == 0 then cb(nil) end
+ cb(sel_items[#sel_items])
+ end,
+ }
+ end
+end
+function M.unregister_ui_select() vim.ui.select = ORIGINAL_UI_SELECT end
+
+--------------------------------------------------------------------------------
+-- Built-in pickers
+-- 1. files
+-- 2. buffers
+-- 3. code-symbols
+--------------------------------------------------------------------------------
+
+--- @param opts? { limit?: number }
+function M.files(opts)
+ opts = opts or {}
+ opts.limit = opts.limit or 10000
+
+ local cmd = {}
+ if vim.fn.executable 'rg' then
+ cmd = {
+ 'rg',
+ '--color=never',
+ '--files',
+ '--hidden',
+ '--follow',
+ '-g',
+ '!.git',
+ '-g',
+ '!node_modules',
+ '-g',
+ '!target',
+ }
+ elseif vim.fn.executable 'fd' then
+ cmd = {
+ 'fd',
+ '--color=never',
+ '--type',
+ 'f',
+ '--hidden',
+ '--follow',
+ '--exclude',
+ '.git',
+ '--exclude',
+ 'node_modules',
+ '--exclude',
+ 'target',
+ }
+ elseif vim.fn.executable 'find' then
+ cmd = {
+ 'find',
+ '-type',
+ 'f',
+ '-not',
+ '-path',
+ "'*/.git/*'",
+ '-not',
+ '-path',
+ "'*/node_modules/*'",
+ '-not',
+ '-path',
+ "'*/target/*'",
+ '-printf',
+ "'%P\n'",
+ }
+ end
+
+ if #cmd == 0 then
+ vim.notify('rg/fd/find executable not found: cannot list files', vim.log.levels.ERROR)
+ return
+ end
+
+ -- Keep track of the job that will list files independent from the picker. We
+ -- will stream lines from this process to the picker as they come in:
+ local job_inf = { id = 0, proc_lines = {}, notified_over_limit = false }
+
+ -- Initially, create the picker with no items:
+ local picker = M.create_picker {
+ multi = true,
+ items = {},
+
+ format_item = function(item)
+ local icon_inf = require('my.icons').get { filename = tostring(item) }
+ return { h('text', { hl = icon_inf.group }, icon_inf.icon), ' ', item }
+ end,
+
+ --- @params items string[]
+ on_finish = function(items)
+ pcall(vim.fn.jobstop, job_inf.id)
+
+ if #items == 0 then return end
+ if #items == 1 then
+ vim.cmd.edit(items[1])
+ else
+ -- populate quickfix:
+ vim.fn.setqflist(vim
+ .iter(items)
+ :map(
+ function(item)
+ return {
+ filename = item,
+ lnum = 1,
+ col = 1,
+ }
+ end
+ )
+ :totable())
+ vim.cmd.copen()
+ end
+ end,
+
+ mappings = {
+ ['<C-t>'] = function(sel)
+ sel.close()
+ --- @type string[]
+ local items = sel.get_selected_items()
+
+ -- open in new tab:
+ for _, item in ipairs(items) do
+ vim.cmd.tabnew(item)
+ end
+ end,
+
+ ['<C-v>'] = function(sel)
+ sel.close()
+ --- @type string[]
+ local items = sel.get_selected_items()
+
+ -- open in vertical split:
+ for _, item in ipairs(items) do
+ vim.cmd.vsplit(item)
+ end
+ end,
+
+ ['<C-s>'] = function(sel)
+ sel.close()
+ --- @type string[]
+ local items = sel.get_selected_items()
+
+ -- open in horizontal split:
+ for _, item in ipairs(items) do
+ vim.cmd.split(item)
+ end
+ end,
+ },
+ }
+
+ -- Kick off the process that lists the files. As lines come in, send them to
+ -- the picker:
+ job_inf.id = vim.fn.jobstart(cmd, {
+ --- @param data string[]
+ on_stdout = vim.schedule_wrap(function(_chanid, data, _name)
+ local lines = job_inf.proc_lines
+ local function set_lines_as_items_state()
+ picker.set_items(vim
+ .iter(lines)
+ :enumerate()
+ :filter(function(idx, item)
+ -- Filter out an incomplete last line:
+ local is_last_line = idx == #lines
+ if is_last_line and item == '' then return false end
+ return true
+ end)
+ :map(function(_, item) return item end)
+ :totable())
+ end
+
+ -- It's just not a good idea to process large lists with Lua. The default
+ -- limit is 10,000 items, and even crunching through this is iffy on a
+ -- fast laptop. Show a warning and truncate the list in this case.
+ if #lines >= opts.limit then
+ if not job_inf.notified_over_limit then
+ vim.notify('Picker list is too large (truncating list to ' .. opts.limit .. ' items)', vim.log.levels.WARN)
+ job_inf.notified_over_limit = true
+ end
+ return
+ end
+
+ -- :help channel-lines
+
+ local eof = #data == 1 and data[1] == ''
+ if eof then set_lines_as_items_state() end
+
+ -- Complete the previous line:
+ if #lines > 0 then lines[#lines] = lines[#lines] .. table.remove(data, 1) end
+
+ for _, l in ipairs(data) do
+ table.insert(lines, l)
+ end
+
+ set_lines_as_items_state()
+ end),
+ })
+end
+
+function M.buffers()
+ local cwd = vim.fn.getcwd(0, 0)
+ -- ensure that `cwd` ends with a trailing slash:
+ if cwd[#cwd] ~= '/' then cwd = cwd .. '/' end
+
+ --- @type { name: string; changed: number; bufnr: number }[]
+ local bufs = vim.fn.getbufinfo { buflisted = 1 }
+
+ M.create_picker {
+ multi = true,
+ items = bufs,
+
+ --- @param item { name: string; changed: number; bufnr: number }
+ format_item = function(item)
+ local icon_inf = require('my.icons').get { filename = item.name }
+ local item_name = item.name
+ if item_name == '' then item_name = '[No Name]' end
+ -- trim leading `cwd` from the buffer name:
+ if item_name:sub(1, #cwd) == cwd then item_name = item_name:sub(#cwd + 1) end
+
+ return TreeBuilder.new()
+ :put(item.changed == 1 and '[+] ' or ' ')
+ :put({ h('text', { hl = icon_inf.group }, icon_inf.icon), ' ' })
+ :put(item_name)
+ :tree()
+ end,
+
+ --- @params items { bufnr: number }[]
+ on_finish = function(items)
+ if #items == 0 then return end
+ if #items == 1 then
+ vim.cmd.buffer(items[1].bufnr)
+ else
+ -- populate quickfix:
+ vim.fn.setqflist(vim
+ .iter(items)
+ :map(
+ function(item)
+ return {
+ bufnr = item.bufnr,
+ filename = item.name,
+ lnum = 1,
+ col = 1,
+ }
+ end
+ )
+ :totable())
+ vim.cmd.copen()
+ end
+ end,
+
+ mappings = {
+ ['<C-t>'] = function(sel)
+ sel.close()
+ --- @type { bufnr: number }[]
+ local items = sel.get_selected_items()
+
+ -- open in new tab:
+ for _, item in ipairs(items) do
+ vim.cmd.tabnew()
+ vim.cmd.buffer(item.bufnr)
+ end
+ end,
+
+ ['<C-v>'] = function(sel)
+ sel.close()
+ --- @type { bufnr: number }[]
+ local items = sel.get_selected_items()
+
+ -- open in new vertial split:
+ for _, item in ipairs(items) do
+ vim.cmd.vsplit()
+ vim.cmd.buffer(item.bufnr)
+ end
+ end,
+
+ ['<C-s>'] = function(sel)
+ sel.close()
+ --- @type { bufnr: number }[]
+ local items = sel.get_selected_items()
+
+ -- open in horizontal split:
+ for _, item in ipairs(items) do
+ vim.cmd.split()
+ vim.cmd.buffer(item.bufnr)
+ end
+ end,
+
+ ['<C-x>'] = function(sel)
+ local selected_items = sel.get_selected_items()
+ for _, item in ipairs(selected_items) do
+ -- delete the buffer
+ vim.cmd.bdelete(item.bufnr)
+ end
+
+ sel.set_selected_indices {}
+ sel.set_items(
+ vim
+ .iter(sel.get_items())
+ :filter(function(item) return not vim.tbl_contains(selected_items, item) end)
+ :totable()
+ )
+ end,
+ },
+ }
+end
+
+local IS_CODE_SYMBOL_RUNNING = false
+function M.lsp_code_symbols()
+ if IS_CODE_SYMBOL_RUNNING then return end
+ IS_CODE_SYMBOL_RUNNING = true
+
+ -- Avoid callback-hell with a wizard-based "steps"-system. Define each "step"
+ -- sequentially in the code, and wire up the callbacks to call the next step:
+ -- a simple, yet powerful, and easy to understand pattern/approach.
+ local STEPS = {}
+
+ --- @param info vim.lsp.LocationOpts.OnList
+ function STEPS._1_on_symbols(info)
+ M.create_picker {
+ items = info.items,
+ --- @param item { text: string }
+ format_item = function(item)
+ local s = item.text:gsub('<', '<')
+ return s
+ end,
+ on_finish = STEPS._2_on_symbol_picked,
+ }
+ end
+
+ --- @param items { filename: string, lnum: integer, col: integer }[]
+ function STEPS._2_on_symbol_picked(items)
+ if #items == 0 then return STEPS._finally() end
+
+ local item = items[1]
+
+ -- Jump to the file/buffer:
+ local buf = vim.iter(vim.fn.getbufinfo { buflisted = 1 }):find(function(b) return b.name == item.filename end)
+ if buf ~= nil then
+ vim.api.nvim_win_set_buf(0, buf.bufnr)
+ else
+ vim.cmd.edit(item.filename)
+ end
+
+ -- Jump to the specific location:
+ vim.api.nvim_win_set_cursor(0, { item.lnum, item.col - 1 })
+ vim.cmd.normal 'zz'
+
+ STEPS._finally()
+ end
+
+ function STEPS._finally() IS_CODE_SYMBOL_RUNNING = false end
+
+ -- Kick off the async operation:
+ vim.lsp.buf.document_symbol { on_list = STEPS._1_on_symbols }
+end
+
+function M.setup()
+ utils.ucmd('Files', M.files)
+ utils.ucmd('Buffers', M.buffers)
+ utils.ucmd('Lspcodesymbols', M.lsp_code_symbols)
+ M.register_ui_select()
+end
+
+return M
diff --git a/lua/u/buffer.lua b/lua/u/buffer.lua
index 06424f4..41cb645 100644
--- a/lua/u/buffer.lua
+++ b/lua/u/buffer.lua
@@ -1,16 +1,21 @@
local Range = require 'u.range'
+local Renderer = require 'u.renderer'.Renderer
---@class Buffer
---@field buf number
+---@field private renderer Renderer
local Buffer = {}
---@param buf? number
---@return Buffer
function Buffer.from_nr(buf)
if buf == nil or buf == 0 then buf = vim.api.nvim_get_current_buf() end
- local b = { buf = buf }
- setmetatable(b, { __index = Buffer })
- return b
+
+ local renderer = Renderer.new(buf)
+ return setmetatable({
+ buf = buf,
+ renderer = renderer,
+ }, { __index = Buffer })
end
---@return Buffer
@@ -69,4 +74,13 @@ function Buffer:text_object(txt_obj, opts)
return Range.from_text_object(txt_obj, opts)
end
+--- @param event string|string[]
+--- @param opts vim.api.keyset.create_autocmd
+function Buffer:autocmd(event, opts)
+ vim.api.nvim_create_autocmd(event, vim.tbl_extend('force', opts, { buffer = self.buf }))
+end
+
+--- @param tree Tree
+function Buffer:render(tree) return self.renderer:render(tree) end
+
return Buffer
diff --git a/lua/u/range.lua b/lua/u/range.lua
index b7d4d34..4ac45d3 100644
--- a/lua/u/range.lua
+++ b/lua/u/range.lua
@@ -1,9 +1,9 @@
local Pos = require 'u.pos'
local State = require 'u.state'
-local orig_on_yank = vim.highlight.on_yank
+local orig_on_yank = (vim.hl or vim.highlight).on_yank
local on_yank_enabled = true;
-(vim.highlight --[[@as any]]).on_yank = function(opts)
+((vim.hl or vim.highlight) --[[@as any]]).on_yank = function(opts)
if not on_yank_enabled then return end
return orig_on_yank(opts)
end
@@ -493,7 +493,7 @@ function Range:highlight(group, opts)
State.run(self.start.buf, function(s)
if not in_macro then s:track_winview() end
- vim.highlight.range(
+ (vim.hl or vim.highlight).range(
self.start.buf,
ns,
group,
diff --git a/lua/u/renderer.lua b/lua/u/renderer.lua
new file mode 100644
index 0000000..f4030b0
--- /dev/null
+++ b/lua/u/renderer.lua
@@ -0,0 +1,432 @@
+local utils = require 'u.utils'
+
+local M = {}
+
+--- @alias Tag { kind: 'tag'; name: string, attributes: table<string, unknown>, children: Tree }
+--- @alias Node nil | boolean | string | Tag
+--- @alias Tree Node | Node[]
+local TagMetaTable = {}
+
+--- @param name string
+--- @param attributes? table<string, any>
+--- @param children? Node | Node[]
+--- @return Tag
+function M.h(name, attributes, children)
+ return setmetatable({
+ kind = 'tag',
+ name = name,
+ attributes = attributes or {},
+ children = children,
+ }, TagMetaTable)
+end
+
+--------------------------------------------------------------------------------
+-- Renderer class
+--------------------------------------------------------------------------------
+--- @alias RendererExtmark { id?: number; start: [number, number]; stop: [number, number]; opts: any; tag: any }
+
+--- @class Renderer
+--- @field bufnr number
+--- @field ns number
+--- @field changedtick number
+--- @field old { lines: string[]; extmarks: RendererExtmark[] }
+--- @field curr { lines: string[]; extmarks: RendererExtmark[] }
+local Renderer = {}
+Renderer.__index = Renderer
+M.Renderer = Renderer
+
+--- @param x any
+--- @return boolean
+function Renderer.is_tag(x) return type(x) == 'table' and getmetatable(x) == TagMetaTable end
+
+--- @param x any
+--- @return boolean
+function Renderer.is_tag_arr(x)
+ if type(x) ~= 'table' then return false end
+ return #x == 0 or not Renderer.is_tag(x)
+end
+
+--- @param bufnr number|nil
+function Renderer.new(bufnr)
+ if bufnr == nil then bufnr = vim.api.nvim_get_current_buf() end
+
+ if vim.b[bufnr]._renderer_ns == nil then
+ vim.b[bufnr]._renderer_ns = vim.api.nvim_create_namespace('my.renderer:' .. tostring(bufnr))
+ end
+
+ local self = setmetatable({
+ bufnr = bufnr,
+ ns = vim.b[bufnr]._renderer_ns,
+ changedtick = 0,
+ old = { lines = {}, extmarks = {} },
+ curr = { lines = {}, extmarks = {} },
+ }, Renderer)
+ return self
+end
+
+--- @param opts {
+--- tree: Tree;
+--- on_tag?: fun(tag: Tag, start0: [number, number], stop0: [number, number]): any;
+--- }
+function Renderer.markup_to_lines(opts)
+ --- @type string[]
+ local lines = {}
+
+ local curr_line1 = 1
+ local curr_col1 = 1 -- exclusive: sits one position **beyond** the last inserted text
+ --- @param s string
+ local function put(s)
+ lines[curr_line1] = (lines[curr_line1] or '') .. s
+ curr_col1 = #lines[curr_line1] + 1
+ end
+ local function put_line()
+ table.insert(lines, '')
+ curr_line1 = curr_line1 + 1
+ curr_col1 = 1
+ end
+
+ --- @param node Node
+ local function visit(node)
+ if node == nil or type(node) == 'boolean' then return end
+
+ if type(node) == 'string' then
+ local node_lines = vim.split(node, '\n')
+ for lnum, s in ipairs(node_lines) do
+ if lnum > 1 then put_line() end
+ put(s)
+ end
+ elseif Renderer.is_tag(node) then
+ local start0 = { curr_line1 - 1, curr_col1 - 1 }
+
+ -- visit the children:
+ if Renderer.is_tag_arr(node.children) then
+ for _, child in ipairs(node.children) do
+ -- newlines are not controlled by array entries, do NOT output a line here:
+ visit(child)
+ end
+ else
+ visit(node.children)
+ end
+
+ local stop0 = { curr_line1 - 1, curr_col1 - 1 }
+ if opts.on_tag then opts.on_tag(node, start0, stop0) end
+ elseif Renderer.is_tag_arr(node) then
+ for _, child in ipairs(node) do
+ -- newlines are not controlled by array entries, do NOT output a line here:
+ visit(child)
+ end
+ end
+ end
+ visit(opts.tree)
+
+ return lines
+end
+
+--- @param opts {
+--- tree: string;
+--- format_tag?: fun(tag: Tag): string;
+--- }
+function Renderer.markup_to_string(opts) return table.concat(Renderer.markup_to_lines(opts), '\n') end
+
+--- @param tree Tree
+function Renderer:render(tree)
+ local changedtick = vim.b[self.bufnr].changedtick
+ if changedtick ~= self.changedtick then
+ self.curr = { lines = vim.api.nvim_buf_get_lines(self.bufnr, 0, -1, false) }
+ self.changedtick = changedtick
+ end
+
+ --- @type RendererExtmark[]
+ local extmarks = {}
+
+ --- @type string[]
+ local lines = Renderer.markup_to_lines {
+ tree = tree,
+
+ on_tag = function(tag, start0, stop0)
+ if tag.name == 'text' then
+ local hl = tag.attributes.hl
+ if type(hl) == 'string' then
+ tag.attributes.extmark = tag.attributes.extmark or {}
+ tag.attributes.extmark.hl_group = tag.attributes.extmark.hl_group or hl
+ end
+
+ local extmark = tag.attributes.extmark
+
+ -- Force creating an extmark if there are key handlers. To accurately
+ -- sense the bounds of the text, we need an extmark:
+ if tag.attributes.on_key or tag.attributes.on_typed then extmark = extmark or {} end
+
+ if extmark then
+ table.insert(extmarks, {
+ start = start0,
+ stop = stop0,
+ opts = extmark,
+ tag = tag,
+ })
+ end
+ end
+ end,
+ }
+
+ self.old = self.curr
+ self.curr = { lines = lines, extmarks = extmarks }
+ self:_reconcile()
+end
+
+--- @private
+--- @param info string
+--- @param start integer
+--- @param end_ integer
+--- @param strict_indexing boolean
+--- @param replacement string[]
+function Renderer:_set_lines(info, start, end_, strict_indexing, replacement)
+ self:_log { 'set_lines', self.bufnr, start, end_, strict_indexing, replacement }
+ vim.api.nvim_buf_set_lines(self.bufnr, start, end_, strict_indexing, replacement)
+ self:_log { 'after(' .. info .. ')', vim.api.nvim_buf_get_lines(self.bufnr, 0, -1, false) }
+end
+
+--- @private
+--- @param info string
+--- @param start_row integer
+--- @param start_col integer
+--- @param end_row integer
+--- @param end_col integer
+--- @param replacement string[]
+function Renderer:_set_text(info, start_row, start_col, end_row, end_col, replacement)
+ self:_log { 'set_text', self.bufnr, start_row, start_col, end_row, end_col, replacement }
+ vim.api.nvim_buf_set_text(self.bufnr, start_row, start_col, end_row, end_col, replacement)
+ self:_log { 'after(' .. info .. ')', vim.api.nvim_buf_get_lines(self.bufnr, 0, -1, false) }
+end
+
+--- @private
+function Renderer:_log(...)
+ --
+ -- vim.print(...)
+end
+
+--- @private
+function Renderer:_reconcile()
+ local line_changes = utils.levenshtein(self.old.lines, self.curr.lines)
+ self.old = self.curr
+
+ --
+ -- Step 1: morph the text to the desired state:
+ --
+ self:_log { line_changes = line_changes }
+ for _, line_change in ipairs(line_changes) do
+ local lnum0 = line_change.index - 1
+
+ if line_change.kind == 'add' then
+ self:_set_lines('add-line', lnum0, lnum0, true, { line_change.item })
+ elseif line_change.kind == 'change' then
+ -- Compute inter-line diff, and apply:
+ self:_log '--------------------------------------------------------------------------------'
+ local col_changes = utils.levenshtein(vim.split(line_change.from, ''), vim.split(line_change.to, ''))
+
+ for _, col_change in ipairs(col_changes) do
+ local cnum0 = col_change.index - 1
+ self:_log { line_change = col_change, cnum = cnum0, lnum = lnum0 }
+ if col_change.kind == 'add' then
+ self:_set_text('add-char', lnum0, cnum0, lnum0, cnum0, { col_change.item })
+ elseif col_change.kind == 'change' then
+ self:_set_text('change-char', lnum0, cnum0, lnum0, cnum0 + 1, { col_change.to })
+ elseif col_change.kind == 'delete' then
+ self:_set_text('del-char', lnum0, cnum0, lnum0, cnum0 + 1, {})
+ else
+ -- No change
+ end
+ end
+ elseif line_change.kind == 'delete' then
+ self:_set_lines('del-line', lnum0, lnum0 + 1, true, {})
+ else
+ -- No change
+ end
+ end
+ self.changedtick = vim.b[self.bufnr].changedtick
+
+ --
+ -- Step 2: reconcile extmarks:
+ --
+ -- Clear current extmarks:
+ vim.api.nvim_buf_clear_namespace(self.bufnr, self.ns, 0, -1)
+ -- Set current extmarks:
+ for _, extmark in ipairs(self.curr.extmarks) do
+ extmark.id = vim.api.nvim_buf_set_extmark(
+ self.bufnr,
+ self.ns,
+ extmark.start[1],
+ extmark.start[2],
+ vim.tbl_extend('force', {
+ id = extmark.id,
+ end_row = extmark.stop[1],
+ end_col = extmark.stop[2],
+ }, extmark.opts)
+ )
+ end
+
+ --
+ -- Step 3: setup an updated on_key handler:
+ --
+
+ vim.on_key(nil, self.ns)
+ vim.on_key(function(key, typed)
+ -- Discard if not in the current buffer:
+ if
+ -- do not capture keys in the wrong buffer:
+ vim.api.nvim_get_current_buf() ~= self.bufnr
+ -- do not capture keys in COMMAND mode:
+ or vim.startswith(vim.api.nvim_get_mode().mode, 'c')
+ then
+ return
+ end
+
+ -- find the tag with the smallest intersection that contains the cursor:
+ local pos0 = vim.api.nvim_win_get_cursor(0)
+ pos0[1] = pos0[1] - 1 -- make it actually 0-based
+ local pos_infos = self:get_pos_infos(pos0)
+
+ -- Check the attributes for each matching_tag and fire events if they are
+ -- listening:
+ for _, pos_info in ipairs(pos_infos) do
+ local tag = pos_info.tag
+
+ -- is the tag listening?
+ if tag.attributes.on_key and type(tag.attributes.on_key[key]) == 'function' then
+ -- key:
+ local result = tag.attributes.on_key[key]()
+ if result == '' then return '' end
+ elseif tag.attributes.on_typed and type(tag.attributes.on_typed[typed]) == 'function' then
+ -- typed:
+ local result = tag.attributes.on_typed[typed]()
+ if result == '' then return '' end
+ end
+ end
+ end, self.ns)
+end
+
+--- Returns pairs of extmarks and tags associate with said extmarks. The
+--- returned tags/extmarks are sorted smallest (innermost) to largest
+--- (outermost).
+---
+--- @private (private for now)
+--- @param pos0 [number; number]
+--- @return { extmark: RendererExtmark; tag: Tag; }[]
+function Renderer:get_pos_infos(pos0)
+ local cursor_line0, cursor_col0 = pos0[1], pos0[2]
+
+ -- The cursor (block) occupies **two** extmark spaces: one for it's left
+ -- edge, and one for it's right. We need to do our own intersection test,
+ -- because the NeoVim API is over-inclusive in what it returns:
+ --- @type RendererExtmark[]
+ local intersecting_extmarks = vim
+ .iter(vim.api.nvim_buf_get_extmarks(self.bufnr, self.ns, pos0, pos0, { details = true, overlap = true }))
+ --- @return RendererExtmark
+ :map(function(ext)
+ --- @type number, number, number, { end_row?: number; end_col?: number }|nil
+ local id, line0, col0, details = unpack(ext)
+ local start = { line0, col0 }
+ local stop = { line0, col0 }
+ if details and details.end_row ~= nil and details.end_col ~= nil then
+ stop = { details.end_row, details.end_col }
+ end
+ return { id = id, start = start, stop = stop, opts = details }
+ end)
+ --- @param ext RendererExtmark
+ :filter(function(ext)
+ if ext.stop[1] ~= nil and ext.stop[2] ~= nil then
+ return cursor_line0 >= ext.start[1]
+ and cursor_col0 >= ext.start[2]
+ and cursor_line0 <= ext.stop[1]
+ and cursor_col0 < ext.stop[2]
+ else
+ return true
+ end
+ end)
+ :totable()
+
+ -- Sort the tags into smallest (inner) to largest (outer):
+ table.sort(
+ intersecting_extmarks,
+ --- @param x1 RendererExtmark
+ --- @param x2 RendererExtmark
+ function(x1, x2)
+ if
+ x1.start[1] == x2.start[1]
+ and x1.start[2] == x2.start[2]
+ and x1.stop[1] == x2.stop[1]
+ and x1.stop[2] == x2.stop[2]
+ then
+ return x1.id < x2.id
+ end
+
+ return x1.start[1] >= x2.start[1]
+ and x1.start[2] >= x2.start[2]
+ and x1.stop[1] <= x2.stop[1]
+ and x1.stop[2] <= x2.stop[2]
+ end
+ )
+
+ -- When we set the extmarks in the step above, we captured the IDs of the
+ -- created extmarks in self.curr.extmarks, which also has which tag each
+ -- extmark is associated with. Cross-reference with that list to get a list
+ -- of tags that we need to fire events for:
+ --- @type { extmark: RendererExtmark; tag: Tag }[]
+ local matching_tags = vim
+ .iter(intersecting_extmarks)
+ --- @param ext RendererExtmark
+ :map(function(ext)
+ for _, extmark_cache in ipairs(self.curr.extmarks) do
+ if extmark_cache.id == ext.id then return { extmark = ext, tag = extmark_cache.tag } end
+ end
+ end)
+ :totable()
+
+ return matching_tags
+end
+
+--------------------------------------------------------------------------------
+-- TreeBuilder class
+--------------------------------------------------------------------------------
+
+--- @class TreeBuilder
+--- @field private nodes Node[]
+local TreeBuilder = {}
+TreeBuilder.__index = TreeBuilder
+M.TreeBuilder = TreeBuilder
+
+function TreeBuilder.new()
+ local self = setmetatable({ nodes = {} }, TreeBuilder)
+ return self
+end
+
+--- @param nodes Tree
+--- @return TreeBuilder
+function TreeBuilder:put(nodes)
+ table.insert(self.nodes, nodes)
+ return self
+end
+
+--- @param name string
+--- @param attributes? table<string, any>
+--- @param children? Node | Node[]
+--- @return TreeBuilder
+function TreeBuilder:put_h(name, attributes, children)
+ local tag = M.h(name, attributes, children)
+ table.insert(self.nodes, tag)
+ return self
+end
+
+--- @param fn fun(TreeBuilder): any
+--- @return TreeBuilder
+function TreeBuilder:nest(fn)
+ local nested_writer = TreeBuilder.new()
+ fn(nested_writer)
+ table.insert(self.nodes, nested_writer.nodes)
+ return self
+end
+
+--- @return Tree
+function TreeBuilder:tree() return self.nodes end
+
+return M
diff --git a/lua/u/tracker.lua b/lua/u/tracker.lua
new file mode 100644
index 0000000..cb13659
--- /dev/null
+++ b/lua/u/tracker.lua
@@ -0,0 +1,294 @@
+local M = {}
+
+M.debug = false
+
+--------------------------------------------------------------------------------
+-- class Signal
+--------------------------------------------------------------------------------
+
+--- @class Signal
+--- @field name? string
+--- @field private changing boolean
+--- @field private value any
+--- @field private subscribers table<function, boolean>
+--- @field private on_dispose_callbacks function[]
+local Signal = {}
+M.Signal = Signal
+Signal.__index = Signal
+
+--- @param value any
+--- @param name? string
+--- @return Signal
+function Signal:new(value, name)
+ local obj = setmetatable({
+ name = name,
+ changing = false,
+ value = value,
+ subscribers = {},
+ on_dispose_callbacks = {},
+ }, self)
+ return obj
+end
+
+--- @param value any
+function Signal:set(value)
+ self.value = value
+
+ -- We don't handle cyclic updates:
+ if self.changing then
+ if M.debug then
+ vim.notify('circular dependency detected' .. (self.name and (' in ' .. self.name) or ''), vim.log.levels.WARN)
+ end
+ return
+ end
+
+ local prev_changing = self.changing
+ self.changing = true
+ local ok = true
+ local err = nil
+ for _, cb in ipairs(self.subscribers) do
+ local ok2, err2 = pcall(cb, value)
+ if not ok2 then
+ ok = false
+ err = err or err2
+ end
+ end
+ self.changing = prev_changing
+
+ if not ok then
+ vim.notify(
+ 'error notifying' .. (self.name and (' in ' .. self.name) or '') .. ': ' .. tostring(err),
+ vim.log.levels.WARN
+ )
+ error(err)
+ end
+end
+
+--- @return any
+function Signal:get()
+ local ctx = M.ExecutionContext.current()
+ if ctx then ctx:track(self) end
+ return self.value
+end
+
+--- @param fn function
+function Signal:update(fn) self:set(fn(self.value)) end
+
+--- @generic U
+--- @param fn fun(value: T): U
+--- @return Signal --<U>
+function Signal:map(fn)
+ local mapped_signal = M.create_memo(function()
+ local value = self:get()
+ return fn(value)
+ end, self.name and self.name .. ':mapped' or nil)
+ return mapped_signal
+end
+
+--- @return Signal
+function Signal:clone()
+ return self:map(function(x) return x end)
+end
+
+--- @param fn fun(value: T): boolean
+--- @return Signal -- <T>
+function Signal:filter(fn)
+ local filtered_signal = M.create_signal(nil, self.name and self.name .. ':filtered' or nil)
+ local unsubscribe_from_self = self:subscribe(function(value)
+ if fn(value) then filtered_signal:set(value) end
+ end)
+ filtered_signal:on_dispose(unsubscribe_from_self)
+ return filtered_signal
+end
+
+--- @param ms number
+--- @return Signal -- <T>
+function Signal:debounce(ms)
+ local function set_timeout(timeout, callback)
+ local timer = (vim.uv or vim.loop).new_timer()
+ timer:start(timeout, 0, function()
+ timer:stop()
+ timer:close()
+ callback()
+ end)
+ return timer
+ end
+
+ local filtered = M.create_signal(self.value, self.name and self.name .. ':debounced' or nil)
+
+ --- @type {
+ -- queued: { value: T, ts: number }[]
+ -- timer?: uv_timer_t
+ -- }
+ local state = { queued = {}, timer = nil }
+ local function clear_timeout()
+ if state.timer == nil then return end
+ pcall(function()
+ state.timer:stop()
+ state.timer:close()
+ end)
+ state.timer = nil
+ end
+
+ local unsubscribe_from_self = self:subscribe(function(value)
+ -- Stop any previously running timer:
+ if state.timer then clear_timeout() end
+ local now_ms = (vim.uv or vim.loop).hrtime() / 1e6
+
+ -- If there is anything older than `ms` in our queue, emit it:
+ local older_than_ms = vim.iter(state.queued):filter(function(item) return now_ms - item.ts > ms end):totable()
+ local last_older_than_ms = older_than_ms[#older_than_ms]
+ if last_older_than_ms then
+ filtered:set(last_older_than_ms.value)
+ state.queued = {}
+ end
+
+ -- overwrite anything young enough
+ table.insert(state.queued, { value = value, ts = now_ms })
+ state.timer = set_timeout(ms, function()
+ vim.schedule(function() filtered:set(value) end)
+ -- If a timer was allowed to run to completion, that means that no other
+ -- item has been queued, since the timer is reset every time a new item
+ -- comes in. This means we can reset the queue
+ clear_timeout()
+ state.queued = {}
+ end)
+ end)
+ filtered:on_dispose(unsubscribe_from_self)
+
+ return filtered
+end
+
+--- @param callback function
+function Signal:subscribe(callback)
+ table.insert(self.subscribers, callback)
+ return function() self:unsubscribe(callback) end
+end
+
+--- @param callback function
+function Signal:on_dispose(callback) table.insert(self.on_dispose_callbacks, callback) end
+
+--- @param callback function
+function Signal:unsubscribe(callback)
+ for i, cb in ipairs(self.subscribers) do
+ if cb == callback then
+ table.remove(self.subscribers, i)
+ break
+ end
+ end
+end
+
+function Signal:dispose()
+ self.subscribers = {}
+ for _, callback in ipairs(self.on_dispose_callbacks) do
+ callback()
+ end
+end
+
+--------------------------------------------------------------------------------
+-- class ExecutionContext
+--------------------------------------------------------------------------------
+
+CURRENT_CONTEXT = nil
+
+--- @class ExecutionContext
+--- @field signals table<Signal, boolean>
+local ExecutionContext = {}
+M.ExecutionContext = ExecutionContext
+ExecutionContext.__index = ExecutionContext
+
+--- @return ExecutionContext
+function ExecutionContext:new()
+ return setmetatable({
+ signals = {},
+ subscribers = {},
+ }, ExecutionContext)
+end
+
+function ExecutionContext.current() return CURRENT_CONTEXT end
+
+--- @param fn function
+--- @param ctx ExecutionContext
+function ExecutionContext:run(fn, ctx)
+ local oldCtx = CURRENT_CONTEXT
+ CURRENT_CONTEXT = ctx
+ local result
+ local success, err = pcall(function() result = fn() end)
+
+ CURRENT_CONTEXT = oldCtx
+
+ if not success then error(err) end
+
+ return result
+end
+
+function ExecutionContext:track(signal) self.signals[signal] = true end
+
+--- @param callback function
+function ExecutionContext:subscribe(callback)
+ local wrapped_callback = function() callback() end
+ for signal in pairs(self.signals) do
+ signal:subscribe(wrapped_callback)
+ end
+
+ return function()
+ for signal in pairs(self.signals) do
+ signal:unsubscribe(wrapped_callback)
+ end
+ end
+end
+
+function ExecutionContext:dispose()
+ for signal, _ in pairs(self.signals) do
+ signal:dispose()
+ end
+ self.signals = {}
+end
+
+--------------------------------------------------------------------------------
+-- Helpers
+--------------------------------------------------------------------------------
+
+--- @param value any
+--- @param name? string
+--- @return Signal
+function M.create_signal(value, name) return Signal:new(value, name) end
+
+--- @param fn function
+--- @param name? string
+--- @return Signal
+function M.create_memo(fn, name)
+ --- @type Signal
+ local result
+ local unsubscribe = M.create_effect(function()
+ local value = fn()
+ if name and M.debug then vim.notify(name) end
+ if result then
+ result:set(value)
+ else
+ result = M.create_signal(value, name and ('m.s:' .. name) or nil)
+ end
+ end, name)
+ result:on_dispose(unsubscribe)
+ return result
+end
+
+--- @param fn function
+--- @param name? string
+function M.create_effect(fn, name)
+ local ctx = M.ExecutionContext:new()
+ M.ExecutionContext:run(fn, ctx)
+ return ctx:subscribe(function()
+ if name and M.debug then
+ local deps = vim
+ .iter(vim.tbl_keys(ctx.signals))
+ :map(function(s) return s.name end)
+ :filter(function(nm) return nm ~= nil end)
+ :join ','
+ vim.notify(name .. '(deps=' .. deps .. ')')
+ end
+ fn()
+ end)
+end
+
+return M
diff --git a/lua/u/utils.lua b/lua/u/utils.lua
index 228a9d2..ffe1d88 100644
--- a/lua/u/utils.lua
+++ b/lua/u/utils.lua
@@ -8,6 +8,18 @@ local M = {}
---@alias KeyMaps table<string, fun(): any | string> }
---@alias CmdArgs { args: string; bang: boolean; count: number; fargs: string[]; line1: number; line2: number; mods: string; name: string; range: 0|1|2; reg: string; smods: any; info: Range|nil }
+--- @generic T
+--- @param x `T`
+--- @param message? string
+--- @return T
+function M.dbg(x, message)
+ local t = {}
+ if message ~= nil then table.insert(t, message) end
+ table.insert(t, x)
+ vim.print(t)
+ return x
+end
+
--- A utility for creating user commands that also pre-computes useful information
--- and attaches it to the arguments.
---
@@ -107,28 +119,97 @@ function M.repeatablemap(mode, lhs, rhs, opts)
end, vim.tbl_extend('force', opts or {}, { expr = true }))
end
-function M.get_editor_dimensions()
- local w = 0
- local h = 0
- local tabnr = vim.api.nvim_get_current_tabpage()
- for _, winid in ipairs(vim.api.nvim_list_wins()) do
- local tabpage = vim.api.nvim_win_get_tabpage(winid)
- if tabpage == tabnr then
- local pos = vim.api.nvim_win_get_position(winid)
- local r, c = pos[1], pos[2]
- local win_w = vim.api.nvim_win_get_width(winid)
- local win_h = vim.api.nvim_win_get_height(winid)
- local right = c + win_w
- local bottom = r + win_h
- if right > w then w = right end
- if bottom > h then h = bottom end
+function M.get_editor_dimensions() return { width = vim.go.columns, height = vim.go.lines } end
+
+--- @alias LevenshteinChange<T> ({ kind: 'add'; item: T; index: number; } | { kind: 'delete'; item: T; index: number; } | { kind: 'change'; from: T; to: T; index: number; })
+--- @private
+--- @generic T
+--- @param x `T`[]
+--- @param y T[]
+--- @param cost? { of_delete?: fun(x: T): number; of_add?: fun(x: T): number; of_change?: fun(x: T, y: T): number; }
+--- @return LevenshteinChange<T>[]
+function M.levenshtein(x, y, cost)
+ cost = cost or {}
+ local cost_of_delete_f = cost.of_delete or function() return 1 end
+ local cost_of_add_f = cost.of_add or function() return 1 end
+ local cost_of_change_f = cost.of_change or function() return 1 end
+
+ local m, n = #x, #y
+ -- Initialize the distance matrix
+ local dp = {}
+ for i = 0, m do
+ dp[i] = {}
+ for j = 0, n do
+ dp[i][j] = 0
end
end
- if w == 0 or h == 0 then
- w = vim.api.nvim_win_get_width(0)
- h = vim.api.nvim_win_get_height(0)
+
+ -- Fill the base cases
+ for i = 0, m do
+ dp[i][0] = i
end
- return { width = w, height = h }
+ for j = 0, n do
+ dp[0][j] = j
+ end
+
+ -- Compute the Levenshtein distance dynamically
+ for i = 1, m do
+ for j = 1, n do
+ if x[i] == y[j] then
+ dp[i][j] = dp[i - 1][j - 1] -- no cost if items are the same
+ else
+ local costDelete = dp[i - 1][j] + cost_of_delete_f(x[i])
+ local costAdd = dp[i][j - 1] + cost_of_add_f(y[j])
+ local costChange = dp[i - 1][j - 1] + cost_of_change_f(x[i], y[j])
+ dp[i][j] = math.min(costDelete, costAdd, costChange)
+ end
+ end
+ end
+
+ -- Backtrack to find the changes
+ local i = m
+ local j = n
+ --- @type LevenshteinChange[]
+ local changes = {}
+
+ while i > 0 or j > 0 do
+ local default_cost = dp[i][j]
+ local cost_of_change = (i > 0 and j > 0) and dp[i - 1][j - 1] or default_cost
+ local cost_of_add = j > 0 and dp[i][j - 1] or default_cost
+ local cost_of_delete = i > 0 and dp[i - 1][j] or default_cost
+
+ --- @param u number
+ --- @param v number
+ --- @param w number
+ local function is_first_min(u, v, w) return u <= v and u <= w end
+
+ if is_first_min(cost_of_change, cost_of_add, cost_of_delete) then
+ -- potential change
+ if x[i] ~= y[j] then
+ --- @type LevenshteinChange
+ local change = { kind = 'change', from = x[i], index = i, to = y[j] }
+ table.insert(changes, change)
+ end
+ i = i - 1
+ j = j - 1
+ elseif is_first_min(cost_of_add, cost_of_change, cost_of_delete) then
+ -- addition
+ --- @type LevenshteinChange
+ local change = { kind = 'add', item = y[j], index = i + 1 }
+ table.insert(changes, change)
+ j = j - 1
+ elseif is_first_min(cost_of_delete, cost_of_change, cost_of_add) then
+ -- deletion
+ --- @type LevenshteinChange
+ local change = { kind = 'delete', item = x[i], index = i }
+ table.insert(changes, change)
+ i = i - 1
+ else
+ error 'unreachable'
+ end
+ end
+
+ return changes
end
return M
diff --git a/spec/tracker_spec.lua b/spec/tracker_spec.lua
new file mode 100644
index 0000000..5da1a85
--- /dev/null
+++ b/spec/tracker_spec.lua
@@ -0,0 +1,206 @@
+local tracker = require 'u.tracker'
+local Signal = tracker.Signal
+local ExecutionContext = tracker.ExecutionContext
+
+describe('Signal', function()
+ local signal
+
+ before_each(function() signal = Signal:new(0, 'testSignal') end)
+
+ it('should initialize with correct parameters', function()
+ assert.is.equal(signal.value, 0)
+ assert.is.equal(signal.name, 'testSignal')
+ assert.is.not_nil(signal.subscribers)
+ assert.is.equal(#signal.subscribers, 0)
+ assert.is.equal(signal.changing, false)
+ end)
+
+ it('should set new value and notify subscribers', function()
+ local called = false
+ signal:subscribe(function(value)
+ called = true
+ assert.is.equal(value, 42)
+ end)
+
+ signal:set(42)
+ assert.is.equal(called, true)
+ end)
+
+ it('should not notify subscribers during circular dependency', function()
+ signal.changing = true
+ local notified = false
+
+ signal:subscribe(function() notified = true end)
+
+ signal:set(42)
+ assert.is.equal(notified, false) -- No notification should occur
+ end)
+
+ it('should get current value', function()
+ signal:set(100)
+ assert.is.equal(signal:get(), 100)
+ end)
+
+ it('should update value with function', function()
+ signal:set(10)
+ signal:update(function(value) return value * 2 end)
+ assert.is.equal(signal:get(), 20)
+ end)
+
+ it('should dispose subscribers', function()
+ local called = false
+ local unsubscribe = signal:subscribe(function() called = true end)
+
+ unsubscribe()
+ signal:set(10)
+ assert.is.equal(called, false) -- Should not be notified
+ end)
+
+ describe('Signal:map', function()
+ it('should transform the signal value', function()
+ local signal = Signal:new(5)
+ local mapped_signal = signal:map(function(value) return value * 2 end)
+
+ assert.is.equal(mapped_signal:get(), 10) -- Initial transformation
+ signal:set(10)
+ assert.is.equal(mapped_signal:get(), 20) -- Updated transformation
+ end)
+
+ it('should handle empty transformations', function()
+ local signal = Signal:new(nil)
+ local mapped_signal = signal:map(function(value) return value or 'default' end)
+
+ assert.is.equal(mapped_signal:get(), 'default') -- Return default
+ signal:set 'new value'
+ assert.is.equal(mapped_signal:get(), 'new value') -- Return new value
+ end)
+ end)
+
+ describe('Signal:filter', function()
+ it('should only emit values that pass the filter', function()
+ local signal = Signal:new(5)
+ local filtered_signal = signal:filter(function(value) return value > 10 end)
+
+ assert.is.equal(filtered_signal:get(), nil) -- Initial value should not pass
+ signal:set(15)
+ assert.is.equal(filtered_signal:get(), 15) -- Now filtered
+ signal:set(8)
+ assert.is.equal(filtered_signal:get(), 15) -- Does not pass the filter
+ end)
+
+ it('should handle empty initial values', function()
+ local signal = Signal:new(nil)
+ local filtered_signal = signal:filter(function(value) return value ~= nil end)
+
+ assert.is.equal(filtered_signal:get(), nil) -- Should be nil
+ signal:set(10)
+ assert.is.equal(filtered_signal:get(), 10) -- Should pass now
+ end)
+ end)
+
+ describe('create_memo', function()
+ it('should compute a derived value and update when dependencies change', function()
+ local signal = Signal:new(2)
+ local memoized_signal = tracker.create_memo(function() return signal:get() * 2 end)
+
+ assert.is.equal(memoized_signal:get(), 4) -- Initially compute 2 * 2
+
+ signal:set(3)
+ assert.is.equal(memoized_signal:get(), 6) -- Update to 3 * 2 = 6
+
+ signal:set(5)
+ assert.is.equal(memoized_signal:get(), 10) -- Update to 5 * 2 = 10
+ end)
+
+ it('should not recompute if the dependencies do not change', function()
+ local call_count = 0
+ local signal = Signal:new(10)
+ local memoized_signal = tracker.create_memo(function()
+ call_count = call_count + 1
+ return signal:get() + 1
+ end)
+
+ assert.is.equal(memoized_signal:get(), 11) -- Compute first value
+ assert.is.equal(call_count, 1) -- Should compute once
+
+ memoized_signal:get() -- Call again, should use memoized value
+ assert.is.equal(call_count, 1) -- Still should only be one call
+
+ signal:set(10) -- Set the same value
+ assert.is.equal(memoized_signal:get(), 11)
+ assert.is.equal(call_count, 2)
+
+ signal:set(20)
+ assert.is.equal(memoized_signal:get(), 21)
+ assert.is.equal(call_count, 3)
+ end)
+ end)
+
+ describe('create_effect', function()
+ it('should track changes and execute callback', function()
+ local signal = Signal:new(5)
+ local call_count = 0
+
+ tracker.create_effect(function()
+ signal:get() -- track as a dependency
+ call_count = call_count + 1
+ end)
+
+ assert.is.equal(call_count, 1)
+ signal:set(10)
+ assert.is.equal(call_count, 2)
+ end)
+
+ it('should clean up signals and not call after dispose', function()
+ local signal = Signal:new(5)
+ local call_count = 0
+
+ local unsubscribe = tracker.create_effect(function()
+ call_count = call_count + 1
+ return signal:get() * 2
+ end)
+
+ assert.is.equal(call_count, 1) -- Initially calls
+ unsubscribe() -- Unsubscribe the effect
+ signal:set(10) -- Update signal value
+ assert.is.equal(call_count, 1) -- Callback should not be called again
+ end)
+ end)
+end)
+
+describe('ExecutionContext', function()
+ local context
+
+ before_each(function() context = ExecutionContext:new() end)
+
+ it('should initialize a new context', function()
+ assert.is.table(context.signals)
+ assert.is.table(context.subscribers)
+ end)
+
+ it('should track signals', function()
+ local signal = Signal:new(0)
+ context:track(signal)
+
+ assert.is.equal(next(context.signals), signal) -- Check if signal is tracked
+ end)
+
+ it('should subscribe to signals', function()
+ local signal = Signal:new(0)
+ local callback_called = false
+
+ context:track(signal)
+ context:subscribe(function() callback_called = true end)
+
+ signal:set(100)
+ assert.is.equal(callback_called, true) -- Callback should be called
+ end)
+
+ it('should dispose tracked signals', function()
+ local signal = Signal:new(0)
+ context:track(signal)
+
+ context:dispose()
+ assert.is.falsy(next(context.signals)) -- Should not have any tracked signals
+ end)
+end)
diff --git a/spec/utils_spec.lua b/spec/utils_spec.lua
new file mode 100644
index 0000000..75bfdf9
--- /dev/null
+++ b/spec/utils_spec.lua
@@ -0,0 +1,70 @@
+local utils = require 'u.utils'
+
+--- @param s string
+local function split(s) return vim.split(s, '') end
+
+--- @param original string
+--- @param changes LevenshteinChange[]
+local function morph(original, changes)
+ local t = split(original)
+ for _, change in ipairs(changes) do
+ if change.kind == 'add' then
+ table.insert(t, change.index, change.item)
+ elseif change.kind == 'delete' then
+ table.remove(t, change.index)
+ elseif change.kind == 'change' then
+ t[change.index] = change.to
+ end
+ end
+ return vim.iter(t):join ''
+end
+
+describe('utils', function()
+ it('levenshtein', function()
+ local original = 'abc'
+ local result = 'absece'
+ local changes = utils.levenshtein(split(original), split(result))
+ assert.are.same(changes, {
+ {
+ item = 'e',
+ kind = 'add',
+ index = 4,
+ },
+ {
+ item = 'e',
+ kind = 'add',
+ index = 3,
+ },
+ {
+ item = 's',
+ kind = 'add',
+ index = 3,
+ },
+ })
+ assert.are.same(morph(original, changes), result)
+
+ original = 'jonathan'
+ result = 'ajoanthan'
+ changes = utils.levenshtein(split(original), split(result))
+ assert.are.same(changes, {
+ {
+ from = 'a',
+ index = 4,
+ kind = 'change',
+ to = 'n',
+ },
+ {
+ from = 'n',
+ index = 3,
+ kind = 'change',
+ to = 'a',
+ },
+ {
+ index = 1,
+ item = 'a',
+ kind = 'add',
+ },
+ })
+ assert.are.same(morph(original, changes), result)
+ end)
+end)