Simple Argument Parser (and dependency-free pretty printer)

argparse_test.lua

local concat, format = table.concat, string.format

-------------------------------------------------------------------------
--- Pretty Printing
-------------------------------------------------------------------------
function extended_tostring(o, qstring)
	local otype = type(o)
	if otype == "table" then
		local result = {}
		for k,v in pairs(o) do
			result[#result+1] = format("%s = %s", extended_tostring(k), extended_tostring(v, true))
		end
		return "{ "..concat(result, ", ").." }"
	elseif otype == "string" and qstring then
		return format("%q", o)
	else
		return tostring(o)
	end
end
function pprint(v)
	print(extended_tostring(v))
end
function vpprint( ... )
	local args = {...}
	for i = 1, #args do
		print(extended_tostring(args[i]))
	end
end

-------------------------------------------------------------------------
--- Argument Parsing
-------------------------------------------------------------------------
-- examples: 
--           -a -b --compression=gzip /test alpha beta gamma
-------------------------------------------------------------------------
function argparse (argv)
	local result = {}

	for i = 1, #argv do
		local argument = argv[i]
		local parsedArg = argument:gsub("^%-+",""):gsub("^%/","")

		if argument == parsedArg then
			result[#result+1] = argument
		else
			local argkey, argval = parsedArg:match("(.-)=(.*)")
			if argkey then
				result[argkey] = argval
			else
				result[parsedArg] = true
			end
		end
	end

	return result
end

-------------------------------------------------------------------------
--- Main Application Entry
-------------------------------------------------------------------------
assert(arg)
pprint(argparse(arg))