swap_ternary.lua

-- swap_ternary.lua

local ts = require('vim.treesitter')
local get_node_text = ts.get_node_text
local ts_utils = require("nvim-treesitter.ts_utils") -- requires nvim-treesitter
local parsers = require("nvim-treesitter.parsers")

local M = {}

local function get_ternary_node(node)
	if not node then
		return
	end

	if node:type() ~= "conditional_expression" then
		node = node:parent()
		return get_ternary_node(node)
	end

	return node
end

function M.swap_ternary()
	local bufnr = vim.api.nvim_get_current_buf()
	local lang = parsers.get_buf_lang(bufnr)

	if not parsers.has_parser(lang) then
		print("No treesitter parser for current language")
		return
	end

	local node = ts_utils.get_node_at_cursor(0)
	local ternary_node = get_ternary_node(node)

	if not ternary_node then
		return
	end

	local t_consequence = ternary_node:field("consequence")
	local result = ""
	local t_alternate = ternary_node:field("alternative")
	for i = 1, #t_alternate do
		local text = get_node_text(t_alternate[i], bufnr)
		result = result .. text
	end
	result = result .. " : "
	for i = 1, #t_consequence do
		local text = get_node_text(t_consequence[i], bufnr)
		result = result .. text
	end

	local t = {}
	local lines = string.gmatch(result, "[^\r\n]+")
	for line in lines do
		table.insert(t, line)
	end

	-- replace the ternary with the swapped text
	local start_row, start_col = t_consequence[1]:start()
	local end_row, end_col = t_alternate[#t_alternate]:end_()
	vim.api.nvim_buf_set_text(bufnr, start_row, start_col, end_row, end_col, t)
end

return M