Babar is an experimental language that uses these Speech Acts to communicate. It also combines one of the other ideas of McCarthy, that is of beliefs and goals. The ultimate aim in the language is discover ways of thinking about computers and communicating with them based on the way that we communicate with each other. The state of a computer at any given point in time can be very complex and hard to understand. If we ascribe this state to be a “belief”, it becomes easier to understand and thus easier to program.
The Babar REPL has internal commitments and internal beliefs. The goal of the Babar REPL is to keep all of its commitments. Speech acts are used to “convince” Babar of beliefs and to make “requests” that form commitments. The Babar REPL continually checks to see if it needs to fulfill a commitments. It fulfills them based on its beliefs. As an optional configuration, the REPL will speak aloud its beliefs as the become true – or as it “holds” the belief.
;Request/Query request *dog fn  :bark. query request-value *dog ;=> :bark query request-completed *dog? ;=> "2013-05-17T19:58:07.882" query request-is-done? ;=> true