argv.lua

local argv = safeinit(...)

local i18n = require "i18n"

--- getopt(argv, optstring [, nonoptions])
--- adapted from https://github.com/skeeto/getopt-lua/blob/master/getopt.lua
--
-- Returns a closure suitable for "for ... in" loops. On each call the
-- closure returns the next (option, optarg). For unknown options, it
-- returns ('?', option). When a required optarg is missing, it returns
-- (':', option). It's reasonable to continue parsing after errors.
-- Returns nil when done.
--
-- The optstring follows the same format as POSIX getopt(3). However,
-- this function will never print output on its own.
--
-- Non-option arguments are accumulated, in order, in the optional
-- "nonoptions" table. If a "--" argument is encountered, appends the
-- remaining arguments to the nonoptions table and returns nil.
--
-- The input argv table is left unmodified.
function argv.getopt(argv, optstring, nonoptions)
	local optind = 1
	local optpos = 2
	nonoptions = nonoptions or {}
	return function()
		while true do
			local arg = argv[optind]
			if arg == nil then
				return nil
			elseif arg == '--' then
				for i = optind + 1, #argv do
					table.insert(nonoptions, argv[i])
				end
				return nil
			elseif arg:sub(1, 1) == '-' then
				local opt = arg:sub(optpos, optpos)
				local start, stop = optstring:find(opt .. ':?')
				if not start then
					optind = optind + 1
					optpos = 2
					return '?', opt
				elseif stop > start and #arg > optpos then
					local optarg = arg:sub(optpos + 1)
					optind = optind + 1
					optpos = 2
					return opt, optarg
				elseif stop > start then
					local optarg = argv[optind + 1]
					optind = optind + 2
					optpos = 2
					if optarg == nil then
						return ':', opt
					end
					return opt, optarg
				else
					optpos = optpos + 1
					if optpos > #arg then
						optind = optind + 1
						optpos = 2
					end
					return opt, nil
				end
			else
				optind = optind + 1
				table.insert(nonoptions, arg)
			end
		end
	end
end

function argv.parse(args)
	local function usage()
		print(i18n.cli_usage)
		os.exit(1)
	end
	local nonopts = {}
	local opts = {}
	local optmap = {
		c = "host",
		p = "port",
		n = "nick",
	}
	table.remove(args, 1)
	for opt, arg in argv.getopt(args, 'c:p:n:', nonopts) do
		if optmap[opt] then
			opts[optmap[opt]] = arg
		elseif opt == '?' then
			printf("unknown option: %s", arg)
			usage()
		elseif opt == ':' then
			printf("missing argument: %s", arg)
			usage()
		end
	end
	if #nonopts ~= 0 then
		print('unexpected arguments: ', table.concat(nonopts, ", "))
		usage()
	end
	return opts
end

return argv