# Display `prompt` in the console and wait for a response
#
# Return the user response, or `null` if EOF.
#
# If `add_history`, the user response is added to the history.
fun prompt(prompt: Text, add_history: nullable Bool): nullable String
do
	printn prompt
	var res = stdin.read_line
	if res == "" and stdin.eof then return null
	return res
end