Module:If preview/sandbox

 local p = {}
 local getArgs = require("Module:Arguments").getArgs
 local yn = require("Module:Yesno")
 local cfg = mw.loadData('Module:If preview/configuration')
 p.pvwc = p.pvwc or package.loaded["Module:If preview/preview warning counter"]
	or require("Module:If preview/preview warning counter")

 --[[
 main

 This function returns either the first argument or second argument passed to
 this module, depending on whether the page is being previewed.

 ]]
 function p.main(frame)
	local args = getArgs(frame)
	if cfg.preview then
		return args[1] or ''
	else
		return args[2] or ''
	end
 end

 --[[
 pmain

 This function returns either the first argument or second argument passed to
 this module's parent (i.e. template using this module), depending on whether it
 is being previewed.

 ]]
 function p.pmain(frame)
	return p.main(frame:getParent())
 end

 local function warning_text(warning)
	return mw.ustring.format(
		cfg.warning_infrastructure,
		cfg.templatestyles,
		warning
	)
 end

 function p._warning(args)
	
	local warning = args[1] and args[1]:match('^%s*(.-)%s*$') or ''
	if warning == '' then
		return warning_text(cfg.missing_warning)
	end
	
	if not cfg.preview then return '' end
	
	if yn(args['consolewarning']) then mw.addWarning('[' .. p.pvwc.incr() .. '] ' .. (args[1] or cfg.missing_warning)) end
	return warning_text(warning)
 end

 --[[
 warning

 This function returns a "preview warning", which is the first argument marked
 up with HTML and some supporting text, depending on whether the page is being previewed.

 ]]
 -- function p.warning(frame)
 -- 	mw.addWarning(frame.args[1] or cfg.missing_warning)
 -- 	return p._warning(frame.args)
 -- end

 --[[
 warning, but for pass-through templates like {{preview warning}}
 ]]
 function p.pwarning(frame)
	local args = getArgs(frame)
	return p._warning(args)
 end

 --[[
 Does both mw.addWarning and preview warning
 ]]

 function p.warn(text)
	if text == nil or text == "" then return "" end
	mw.addWarning('[' .. p.pvwc.incr() .. '] ' .. text)
	return p._warning({text})
 end

 --[[
 Console warning
 ]]
 function p.consoleWarning(frame)
	local args = getArgs(frame)
	mw.addWarning('[' .. p.pvwc.incr() .. '] ' .. (args[1] or cfg.missing_warning))
	return ''
 end

 return p