module IO::Event::Selector

def self.default(env = ENV)
	if name = env['IO_EVENT_SELECTOR']&.to_sym
		if const_defined?(name)
			return const_get(name)
		else
			warn "Could not find IO_EVENT_SELECTOR=#{name}!"
		end
	end
	
	if self.const_defined?(:EPoll)
		return EPoll
	elsif self.const_defined?(:KQueue)
		return KQueue
	else
		return Select
	end
end

def self.new(loop, env = ENV)
	selector = default(env).new(loop)
	
	if debug = env['IO_EVENT_DEBUG_SELECTOR']
		selector = Debug::Selector.new(selector)
	end
	
	return selector
end