Module:Yesno

--[[ This module is a helper module to be used by other modules; it may not be designed to be invoked directly. See Near-Reality:Lua/Helper modules for a full list and more information.

Module	Function	Type	Use
Yesno	(arg)	Any value	Reads arg for yes/no and returns the appropriate boolean or nil
	(arg1,arg2)	Any value, Any value	Reads arg1 for yes/no and returns the appropriate boolean; returns arg2 if arg1 was not an applicable value

--]]

--

-- Used to evaluate args to booleans where applicable
--
-- Based on <https://en.wikipedia.org/wiki/Module:Yesno>
-- see page history there for contributors
--

return function( arg, default )
    arg = type( arg ) == 'string' and mw.ustring.lower( arg ) or arg

    if arg == nil then
        return nil
    end

    if
        arg == true or
        arg == 'yes' or
        arg == 'y' or
        arg == 'true' or
        tonumber( arg ) ==  1
    then
        return true
    end

    if
        arg == false or
        arg == 'no' or
        arg == 'n' or
        arg == 'false' or
        tonumber( arg ) == 0
    then
        return false
    end

    return default
end