Extremely toy ELIZA in Ruby    (February 25th, 2026)
===========================

The Art of Prolog contains a very simplified toy Prolog implementation of ELIZA (section 14.3, p. 275). Here is a Ruby port. I found it interesting how you can nearly converse with something so simple.


Example transcript:

>> I am Eliza. How can I help you?
I am unhappy.
>> How long have you been unhappy?
Six months. Can you help me?
>> What makes you think I help you?
You remind me of my father and brother.
>> Please tell me more about father.
I like teasing father.
>> Does anyone else in your family like teasing father?
No, only me.
>> Please go on.

def respond(s) = puts ">> #{s}"

IMPORTANT = /(father|mother|son|sister|brother|daughter)/i
def eliza(s)
	case s.delete('.?,')
	when /bye/i
		respond "Goodbye. I hope I have helped you."
		exit 0
	when /I am (.+)/i
		respond "How long have you been #{$1}?"
	when /(.+) you (.+) me/i
		respond "What makes you think I #{$2} you?"
	when /I like (.+)/i
		respond "Does anyone else in your family like #{$1}?"
	when /I feel .+/i
		respond "Do you often feel that way?"
	when IMPORTANT
		respond "Please tell me more about #{$1}."
	else
		respond "Please go on."
	end
end

respond "I am Eliza. How can I help you?"
while true do
	eliza gets()
end

~/languages/eliza