refactor(nvim): rewrite extmark plugin

1 files changed, 12 insertions, 84 deletions

diff --git a/plugin/50-extmarks.lua b/plugin/50-extmarks.lua
index 593321d..2cb7862 100644
--- a/plugin/50-extmarks.lua
+++ b/plugin/50-extmarks.lua
@@ -1,41 +1,16 @@
 --
 -- 50-extmarks.lua
 --
--- * Creates a global highlight namespace for extended marks.
--- * Keeps track of the current global highlight namespace in `vim.g.hl_ns`.
--- * Creates an autocommand that marks matches in each buffer on 'FileType' and keeps them in sync
---   as the buffer changes. Marks follow the theme on their own: the `dotfiles.Todo` group links to
---   `Todo`, so a colorscheme / 'background' change re-colors them with no extra wiring.
---   For now, only "TODO" strings are marked but the system can be easily extended by adding items
---   in `marks`.
---   Doesn't support multi-line patterns.
---
--- Global variables:
---   `vim.g.hl_ns`: global highlight namespace
+-- * Marks "TODO" strings through the dotfiles.extmark engine.
+-- * Only "TODO" in comments is marked (in markdown, "TODO" outside code), classified from the
+--   treesitter tree; with no parser for the filetype, every "TODO" is marked.
+-- * Multi-line patterns are not supported.
 --
 -- User commands:
---   `ExtmarkToggle`: toggle extended marks highlight namespace
+--   ExtmarkToggle: toggle the extended-marks highlight namespace
 --
 
-vim.g.hl_ns = 0
-
-local extmarks_hl_ns = vim.api.nvim_create_namespace("dotfiles_extmarks")
-
-local hl_group_todo = "dotfiles.Todo"
-vim.api.nvim_set_hl(extmarks_hl_ns, hl_group_todo, { link = "Todo" })
-
--- Wrapper around `nvim_set_hl_ns()`; sets the global highlight namespace to `hl_ns` and save it to
--- `vim.g.hl_ns`. Useful because the global highlight namespace is not saved anywhere by default.
-local function set_global_hl_ns(hl_ns)
-	vim.g.hl_ns = hl_ns
-	vim.api.nvim_set_hl_ns(hl_ns)
-end
-
--- Toggles extended marks highlight namespace
-local function toggle_marks()
-	local new_hl_ns = vim.g.hl_ns == 0 and extmarks_hl_ns or 0
-	set_global_hl_ns(new_hl_ns)
-end
+local extmark = require("dotfiles.extmark")
 
 -- Parses the treesitter tree synchronously, including injections, in the 0-based, end-exclusive
 -- line range `first`:`last` of buffer `buf`.
@@ -106,59 +81,12 @@ local function find_todo(buf, first, last)
 	end
 end
 
--- List of extended marks to apply with `mark_all()`
---
--- Each item is a table with two fields: `hl_group`, the name of the highlight group to use
--- for the marks, and `find`, which must return an iterator over the positions to mark (see
--- `find_todo()` for the format).
-local marks = {
-	{ hl_group = hl_group_todo, find = find_todo },
-}
-
--- Updates extended marks in buffer `buf` in range `first`:`last`.
--- For each item in `marks`, sets extended marks on positions returned by `item.find` to the
--- highlight group `item.hl_group`.
-local function mark_all(buf, first, last)
-	vim.api.nvim_buf_clear_namespace(buf, extmarks_hl_ns, first, last)
-	for _, marks_opts in ipairs(marks) do
-		for p in marks_opts.find(buf, first, last) do
-			vim.api.nvim_buf_set_extmark(
-				buf,
-				extmarks_hl_ns,
-				p.y,
-				p.x1,
-				{ end_col = p.x2, hl_group = marks_opts.hl_group }
-			)
-		end
-	end
-end
-
--- Create extended marks in buffer `ev.buf` and updates them when the buffer changes.
-local function watch_extmarks(ev)
-	mark_all(ev.buf, 0, -1)
-	if vim.b[ev.buf].dotfiles_todo_attached then
-		return
-	end
-	vim.b[ev.buf].dotfiles_todo_attached = true
-	vim.api.nvim_buf_attach(ev.buf, false, {
-		on_lines = function(_, b, _, first, _, last_new)
-			vim.schedule(function()
-				if vim.api.nvim_buf_is_valid(b) then
-					mark_all(b, first, last_new)
-				end
-			end)
-		end,
-	})
-end
+extmark.register("dotfiles.Todo", { link = "Todo" }, find_todo)
 
 ----------------------------------------------------------------------------------------------------
 
-vim.api.nvim_create_autocmd("FileType", {
-	desc = "Set extended marks watcher",
-	group = vim.g.dotfiles.augroup,
-	callback = watch_extmarks,
-})
-
-vim.api.nvim_create_user_command("ExtmarkToggle", toggle_marks, { desc = "Toggle extended marks" })
-
-set_global_hl_ns(extmarks_hl_ns)
+vim.api.nvim_create_user_command(
+	"ExtmarkToggle",
+	extmark.toggle,
+	{ desc = "Toggle extended marks" }
+)