nvim: add markdown quote ftplugin

I increase/decrease quote levels a lot, so I figured I'd write a small
thing for doing that more easily in visual mode.

This isn't without problems. Known bugs:
* In normal-mode, it's a bit slow (waiting for more inputs? possible,
  but if you give it more inputs it just does it twice).
* You cannot increase/decrease indentation with <</>> with this on. This
  is mostly a bummer for code blocks.
* Doesn't work with indentation-based quoting, rather than >.

But it's good enough for me, eh?

1 files changed, 76 insertions, 0 deletions

diff --git a/dot_config/nvim/ftplugin/markdown_quote.lua b/dot_config/nvim/ftplugin/markdown_quote.lua
new file mode 100644
index 0000000..3a57c20
--- /dev/null
+++ b/dot_config/nvim/ftplugin/markdown_quote.lua
@@ -0,0 +1,76 @@
+local api = vim.api
+local fn  = vim.fn
+
+local buffer = 0 -- operate on current buffer
+
+local function location(opts)
+	-- if called from a command, we don't have event info
+	if not opts then
+		opts = {
+			line1 = fn.line 'v',
+			line2 = fn.line '.',
+		}
+	end
+
+	if opts.line1 > opts.line2 then
+		opts.line1, opts.line2 = opts.line2, opts.line1
+	end
+
+	-- nvim api lines are zero-based end-exclusive
+	opts.line1 = opts.line1 - 1
+	return opts
+end
+
+local function mdquote(opts)
+	opts = location(opts)
+
+	-- 1. get all of the matching lines
+	local lines = api.nvim_buf_get_lines(buffer, opts.line1, opts.line2, true)
+
+	-- 2. edit them appropriately
+	for i, line in ipairs(lines) do
+		-- prepend a ">" and a " ",
+		-- unless the first character was already ">" or whitespace
+		-- so prepend " " first unless the above is true
+		if line:match '^$' then
+		elseif line:match '^[%s>]' then
+			lines[i] = '>' .. line
+		else
+			lines[i] = '> ' .. line
+		end
+	end
+
+	-- 3. insert them back
+	api.nvim_buf_set_lines(buffer, opts.line1, opts.line2, true, lines)
+end
+
+local function mddequote(opts)
+	opts = location(opts)
+
+	-- see mdquote for the steps
+	local lines = api.nvim_buf_get_lines(buffer, opts.line1, opts.line2, true)
+
+	for i, line in ipairs(lines) do
+		-- if the line starts with a "> ", remove both
+		-- elseif the line starts with a ">", remove that
+		-- TODO: I don't handle \t-based quoting
+		if line:match '^> ' then
+			lines[i] = line:sub(3)
+		elseif line:match '^>' then
+			lines[i] = line:sub(2)
+		end
+	end
+
+	api.nvim_buf_set_lines(buffer, opts.line1, opts.line2, true, lines)
+end
+
+api.nvim_buf_create_user_command(buffer, 'MdQuote', mdquote, { range = true })
+api.nvim_buf_create_user_command(buffer, 'MdDeQuote', mddequote, { range = true })
+vim.keymap.set({'n', 'x'}, '>', mdquote, {
+	buffer = true,
+	desc = 'increase quote level of selection',
+})
+vim.keymap.set({'n', 'x'}, '<', mddequote, {
+	buffer = true,
+	desc = 'decrease quote level of selection',
+})