Java tutorial
/** * SusiThoughts * Copyright 30.06.2016 by Michael Peter Christen, @0rb1t3r * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program in the file lgpl21.txt * If not, see <http://www.gnu.org/licenses/>. */ package org.loklak.susi; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import org.json.JSONArray; import org.json.JSONObject; /** * An Argument is a series of thoughts, also known as a 'proof' in automated reasoning. * Within the Susi AI infrastructure this may be considered as the representation of * the short-time memory of thinking inside Susi. */ public class SusiArgument implements Iterable<SusiThought> { private final ArrayList<SusiThought> recall; private final List<SusiAction> actions; /** * Create an empty argument */ public SusiArgument() { this.recall = new ArrayList<>(); this.actions = new ArrayList<>(); } public SusiArgument clone() { SusiArgument c = new SusiArgument(); this.recall.forEach(thought -> c.recall.add(thought)); this.actions.forEach(action -> c.actions.add(action)); return c; } /** * Get an impression of time which elapsed since the start of reasoning in this argument. * This uses the idea that 'time' is not a physical effect but simply the result of a delta operation * on memory states (thus a 'psychic perception') while 'time' in the physical world (in this model) * is just the wrong word for 'causality'. In that context: maybe the "constant perception of time" * is what humans call "self-awareness". This could be the core of an artificial self-awareness. * @return the number of thoughts within this argument, to be considered as perception of time */ public int times() { return this.recall.size(); } /** * The 'mindstate' is the current state of an argument. Its the latest thought. * This is the same operation as a 'top' for stacks. * @return the latest thought in a series of proof steps in an argument */ public SusiThought mindstate() { return remember(0); } /** * The mindmeld is the combination of all thoughts into one. It is a required operation in case * that a previous argument is recalled and used to start a new one. This prevents that thinking * creates ever increasing argument list; instead old arguments can be 'squashed' into one, like * it's done with git commits. * The mindmeld also should have the ability to 'overwrite' old values with new ones. That is done * by considering the new values in a order which makes them more visible than the value before. * @return the squashed thoughts from an argument as one thought */ public SusiThought mindmeld(boolean reverse) { SusiThought meltedMind = new SusiThought(); if (reverse) for (int i = this.recall.size() - 1; i >= 0; i--) meltedMind.mergeData(this.recall.get(i).getData()); else for (int i = 0; i < this.recall.size(); i++) meltedMind.mergeData(this.recall.get(i).getData()); meltedMind.setTimes(times()); // remember the length of the argument to create a perception of time based on number of thoughts return meltedMind; } /** * Remembering the thoughts is essential to recall which thoughts leads to the current mindstate * @param timesBack the number of thoughts backwards from the current mindstate * @return the thought in the past according to the elapsed time of the thoughts */ public SusiThought remember(int timesBack) { int state = this.recall.size() - timesBack - 1; if (state < 0) return new SusiThought(); // empty mind! return this.recall.get(state); } /** * Re-Thinking removes the latest thought from the mind stack. It may be manipulated * by any inference rules and then pushed again to the recall stack. This is needed to * manipulate the backtracking stack within each element of an argument during inference * processing. * This is the same operation as a 'pop' on a stack. * @return the latest thought in the argument, while the argument list shrinks by that element */ public SusiThought rethink() { if (this.recall.size() <= 0) return new SusiThought(); // empty mind! SusiThought rethought = this.recall.remove(this.recall.size() - 1); return rethought; } /** * Creating amnesia means to forget all thoughts in an argument. * This can be used to squash the argument into one which contains the * mindmeld thought from a state before the amnesia is called. * @return the current (now empty) argument */ public SusiArgument amnesia() { this.recall.clear(); return this; } /** * Thinking is a series of thoughts, every new thought appends another thought to the argument. * A special situation may (or may not) occur if one thinking step does not produce a result. * Depending on the inference rule set that may mean that the consideration of the rule containing * the inferences was wrong and should be abandoned. This happens if mindstate().equals(thought). * This is the same operation as a 'push' on a stack. * @param thought the next thought * @return self, the current argument */ public SusiArgument think(SusiThought thought) { this.recall.add(thought); return this; } /** * to remember larger sets of thoughts, we can also think arguments. All of the thoughts of the * new arguments are pushed ontop of the recall thought stack. * @param argument * @return self, the current argument */ public SusiArgument think(SusiArgument argument) { argument.recall.forEach(thought -> think(thought)); return this; } /** * Unification applies a piece of memory within the current argument to a statement * which creates an instantiated statement * TODO: this should support backtracking, thus producing optional several unifications and turning this into a choice point * @param statement * @param depth the maximum depth into the flow. depth == 0 means 'only the last thought' * @return the instantiated statement with elements of the argument applied */ public String unify(String statement, int depth) { for (SusiThought t : this) { if (depth-- < 0) break; statement = t.unify(statement); if (!SusiThought.variable_pattern.matcher(statement).find()) return statement; } if (SusiThought.variable_pattern.matcher(statement).find()) return null; // failure! return statement; } public String unify(String statement) { return unify(statement, Integer.MAX_VALUE); } /** * the iterator returns the thoughts in reverse order, latest thought first */ @Override public Iterator<SusiThought> iterator() { return new Iterator<SusiThought>() { private int p = recall.size(); @Override public boolean hasNext() { return p > 0; } @Override public SusiThought next() { return recall.get(--p); } }; } /** * Every argument may have a set of (re-)actions assigned. * Those (re-)actions are methods to do something with the argument. * @param action one (re-)action on this argument * @return the argument */ public SusiArgument addAction(final SusiAction action) { this.actions.add(action); return this; } /** * To be able to apply (re-)actions to this thought, the actions on the information can be retrieved. * @return the (re-)actions which are applicable to this thought. */ public List<SusiAction> getActions() { return this.actions; } public JSONObject toJSON() { JSONObject json = new JSONObject(true); JSONArray recallJson = new JSONArray(); this.recall.forEach(thought -> recallJson.put(thought)); JSONArray actionsJson = new JSONArray(); this.actions.forEach(action -> actionsJson.put(action.toJSONClone())); json.put("recall", recallJson); json.put("action", actionsJson); return json; } public String toString() { return this.toJSON().toString(); } public static void main(String[] args) { SusiArgument a = new SusiArgument().think(new SusiThought().addObservation("a", "letter-a")); System.out.println(a.unify("the letter $a$")); } }