u.nvim/lua/u/renderer.lua
Jonathan Apodaca d9e6614aa4
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1-based indexing rewrite
2025-04-11 14:10:52 -06:00

524 lines
16 KiB
Lua

local M = {}
local H = {}
--- @alias Tag { kind: 'tag'; name: string, attributes: table<string, unknown>, children: Tree }
--- @alias Node nil | boolean | string | Tag
--- @alias Tree Node | Node[]
--- @param name string
--- @param attributes? table<string, any>
--- @param children? Node | Node[]
--- @return Tag
function M.h(name, attributes, children)
return {
kind = 'tag',
name = name,
attributes = attributes or {},
children = children,
}
end
-- Renderer {{{
--- @alias RendererExtmark { id?: number; start: [number, number]; stop: [number, number]; opts: any; tag: any }
--- @class u.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
--- @private
--- @param x any
--- @return boolean
function Renderer.is_tag(x) return type(x) == 'table' and x.kind == 'tag' end
--- @private
--- @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 --[[@as Node[] ]])
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
-- Set any necessary keymaps:
for _, mode in ipairs { 'i', 'n', 'v', 'x', 'o' } do
for lhs, _ in pairs(tag.attributes[mode .. 'map'] or {}) do
-- Force creating an extmark if there are key handlers. To accurately
-- sense the bounds of the text, we need an extmark:
extmark = extmark or {}
vim.keymap.set(
'n',
lhs,
function() return self:_expr_map_callback('n', lhs) end,
{ buffer = self.bufnr, expr = true, replace_keycodes = true }
)
end
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 start integer
--- @param end_ integer
--- @param strict_indexing boolean
--- @param replacement string[]
function Renderer:_set_lines(start, end_, strict_indexing, replacement)
vim.api.nvim_buf_set_lines(self.bufnr, start, end_, strict_indexing, replacement)
end
--- @private
--- @param start_row integer
--- @param start_col integer
--- @param end_row integer
--- @param end_col integer
--- @param replacement string[]
function Renderer:_set_text(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)
end
--- @private
function Renderer:_reconcile() -- {{{
local line_changes = H.levenshtein(self.old.lines, self.curr.lines)
self.old = self.curr
--
-- Step 1: morph the text to the desired state:
--
for _, line_change in ipairs(line_changes) do
local lnum0 = line_change.index - 1
if line_change.kind == 'add' then
self:_set_lines(lnum0, lnum0, true, { line_change.item })
elseif line_change.kind == 'change' then
-- Compute inter-line diff, and apply:
local col_changes = H.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
if col_change.kind == 'add' then
self:_set_text(lnum0, cnum0, lnum0, cnum0, { col_change.item })
elseif col_change.kind == 'change' then
self:_set_text(lnum0, cnum0, lnum0, cnum0 + 1, { col_change.to })
elseif col_change.kind == 'delete' then
self:_set_text(lnum0, cnum0, lnum0, cnum0 + 1, {})
else
-- No change
end
end
elseif line_change.kind == 'delete' then
self:_set_lines(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
end -- }}}
--- @private
--- @param mode string
--- @param lhs string
function Renderer:_expr_map_callback(mode, lhs) -- {{{
-- 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)
if #pos_infos == 0 then return lhs end
-- Find the first tag that is listening for this event:
local cancel = false
for _, pos_info in ipairs(pos_infos) do
local tag = pos_info.tag
-- is the tag listening?
local f = vim.tbl_get(tag.attributes, mode .. 'map', lhs)
if type(f) == 'function' then
local result = f()
if result == '' then
-- bubble-up to the next tag, but set cancel to true, in case there are
-- no more tags to bubble up to:
cancel = true
else
return result
end
end
end
-- Resort to default behavior:
return cancel and '' or lhs
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 u.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 u.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 u.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 u.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
-- }}}
-- Levenshtein utility {{{
--- @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 H.levenshtein(x, y, cost)
-- At the moment, this whole `cost` plumbing is not used. Deletes have the
-- same cost as Adds or Changes. I can imagine a future, however, where
-- fudging with the costs of operations produces a more optimized change-set
-- that is tailored to working better with how NeoVim manipulates text. I've
-- done no further investigation in this area, however, so it's impossible to
-- tell if such tuning would produce real benefit. For now, I'm leaving this
-- in here even though it's not actively used. Hopefully having this
-- callback-based plumbing does not cause too much of a performance hit to
-- the renderer.
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
-- Fill the base cases
for i = 0, m do
dp[i][0] = i
end
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