Editing Module:Demo

local p = {}

--creates a frame object that cannot access any of the parent's args
--unless a table containing a list keys of not to inherit is provided
function disinherit(frame, onlyTheseKeys)
	frame = frame:getParent() or frame
	local orphan = frame:newChild{}
	orphan.getParent = frame.getParent --returns nil
	if onlyTheseKeys then
		orphan.args = mw.clone(frame.args)
		for _, k in ipairs(onlyTheseKeys) do
			orphan.args[k] = nil
		end
	end
	return orphan, frame
end

function p.get(frame, arg, passArgs)
	local orphan, frame = disinherit(frame, passArgs and {arg or 1})
	local code, noWiki, preserve = frame.args[arg or 1] or ''
	if code:match'nowiki' then
		local placeholder, preserve = ('6'):char(), {}
		code = mw.text.unstripNoWiki(code)
		noWiki = code:gsub('%%', placeholder):gsub('&lt;', '<'):gsub('&gt;', '>')
		for k in noWiki:gmatch('&.-;') do
			if not preserve[k] then
				preserve[k] = true
				table.insert(preserve, (k:gsub('&', '&amp;')))
				noWiki = noWiki:gsub('(&.-;)', '%%%s')
			end
		end
		noWiki = mw.text.nowiki(noWiki):format(unpack(preserve)):gsub(placeholder, '%%')
	end
	return {
		source = noWiki or code,
		output = orphan:preprocess(code),
		frame = frame
	}
end

function p.main(frame, demoTable)
	local show = demoTable or p.get(frame)
	local args = show.frame.args
	args.br = tonumber(args.br or 1) and ('<br>'):rep(args.br or 1) or args.br or ''
	if show[args.result_arg] then
		return show[args.result_arg]
	end
	return string.format('<pre%s>%s</pre>%s%s', args.style and string.format(" style='%s'", args.style) or '', show.source, args.br, show.output)
end

--passing of args into other module without preprocessing
function p.module(frame)
	local orphan, frame = disinherit(frame, {
		'demo_template',
		'demo_module_func',
		'demo_main',
		'demo_br',
		'demo_result_arg'
	})
	local template = frame.args.demo_template and 'Template:'..frame.args.demo_template
	local demoFunc = frame.args.demo_module_func or 'main\n'
	local demoModule = require('Module:%'..frame.args.demo_module)[demoFunc:match('^%s*(.-)%s*$')]
	frame.args.br, frame.args.result_arg = frame.args.demo_br, frame.args.demo_result_arg
	if demoModule then
		local source = template and {'{{', template and '' or '#invoke:', frame.args.demo_template or frame.args.demo_module, template and '' or '|', demoFunc}
		for k, v in pairs(frame.args) do
			table.insert(
				source,
				tonumber(k) and
					'|'..v
					or ('|%s = %s'):format(k, v)
			)
		end
		return p.main(frame, {
			source = mw.text.nowiki(table.concat(source)),
			output = demoModule(orphan),
			frame = frame
		})
	else
		return "ERROR: Invalid module function: "..demoFunc
	end
end

return p