You can use npl in several different ways. You can start an ircbot and talk to it in an irchat, in a REPL manner. Or you can start a daemon and talk to it over HTTP. Or you can use it from python (for this, refer to the nl documentation).
From the root of the nl buildout, do:
$ bin/ircbot some_name
Generating LALR tables
Signed on as some_name_bot.
Joined #nlpbot_some_name.
Now you can talk to the ircbot on freenode at channel #nlpbot_some_name. You provide definitions, facts and rules ending them with a dot, and you ask facts ending them with a question mark. Question facts can contain variables. Whenever you tell or ask something to the bot, you have to address it prefixing your message with its nickname: “some_name_bot: <message>” where <message> is any definition, fact, rule, or question.
You can now also start a daemon, and, as I said, talk to it over HTTP:
$ bin/npldaemon
$
A telnet session now with the daemon:
$ telnet localhost 8280
Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
person are thing.
Noun Person defined.Connection closed by foreign host.