ChatCitizen

This is a chatbot system designed to work under the Citizens2 plugin for Minecraft Spigot servers. It lets you create NPCs you can have conversations with.

The original version of ChatCitizen used AIML, a well-known Java chatbot library, but I decided to write my own system more aligned with the Chatscript C++ library (but in Java). It works fairly well, but like all chatbots it needs a huge amount of data. This is ongoing work.

The code is made up of two parts:

• SimpleChat is the underlying Java library,
• ChatCitizen2 is the Minecraft plugin.

Chatbots primarily consist of patterns and responses. For example:

+(.* $c=~drink .*)
    isdrunk if
        ^refusedrink.
    else
        "One ${$c} coming right up.". addDrink
        {
            +&thanks ^yourewelcome;
        } next
    then;

This pattern responds to anything of the “drink” category being mentioned in the sentence, and assumes you want that drink. There’s another pattern with higher priority that deals with the word “not” preceding the drink, and yet another system for expanding contractions like “don’t”, so you can say “I don’t want a whisky.”

The bit after the first line is code that happens in response to a pattern¹. Here, if you’ve had too much (we keep a count) you get refused. Otherwise you get your drink, and any “thanks” offered will give a “you’re welcome” response. Of these tiny pieces are chatbots made.

Currently, I’ve got a set of shops which use iron ingots or emeralds as a medium of exchange, a poet who talks gibberish, soldiers who can guard you if you ask them, and the publican described above.

Making friends is fun.