KBAgent added to propositional logic

Author: ShobhitLamba

aima-csharp/aima-csharp.csproj

@@ -190,6 +190,12 @@
     <Compile Include="logic\fol\SubsumptionElimination.cs" />
     <Compile Include="logic\fol\Unifier.cs" />
     <Compile Include="logic\fol\VariableCollector.cs" />
+    <Compile Include="logic\propositional\agent\KBAgent.cs" />
+    <Compile Include="logic\propositional\kb\data\Clause.cs" />
+    <Compile Include="logic\propositional\kb\data\ConjunctionOfClauses.cs" />
+    <Compile Include="logic\propositional\kb\data\Literal.cs" />
+    <Compile Include="logic\propositional\kb\data\Model.cs" />
+    <Compile Include="logic\propositional\kb\KnowledgeBase.cs" />
     <Compile Include="obj\Debug\TemporaryGeneratedFile_036C0B5B-1481-4323-8D20-8F5ADCB23D92.cs" />
     <Compile Include="obj\Debug\TemporaryGeneratedFile_5937a670-0e60-4077-877b-f7221da3dda1.cs" />
     <Compile Include="obj\Debug\TemporaryGeneratedFile_E7A71F73-0F8D-4B9B-B56E-8E70B10BC5D3.cs" />

aima-csharp/logic/propositional/agent/KBAgent.cs

@@ -0,0 +1,111 @@
+using aima.core.agent;
+using aima.core.agent.impl;
+using aima.core.logic.propositional.kb;
+using aima.core.logic.propositional.parsing.ast;
+
+namespace aima.core.logic.propositional.agent
+{
+    /**
+     * Artificial Intelligence A Modern Approach (3rd Edition): Figure 7.1, page
+     * 236.<br>
+     * <br>
+     * 
+     * <pre>
+     * function KB-AGENT(percept) returns an action
+     *   persistent: KB, a knowledge base
+     *               t, a counter, initially 0, indicating time
+     *           
+     *   TELL(KB, MAKE-PERCEPT-SENTENCE(percept, t))
+     *   action &lt;- ASK(KB, MAKE-ACTION-QUERY(t))
+     *   TELL(KB, MAKE-ACTION-SENTENCE(action, t))
+     *   t &lt;- t + 1
+     *   return action
+     * 
+     * </pre>
+     * 
+     * Figure 7.1 A generic knowledge-based agent. Given a percept, the agent adds
+     * the percept to its knowledge base, asks the knowledge base for the best
+     * action, and tells the knowledge base that it has in fact taken that action.
+     * 
+     * @author Ciaran O'Reilly
+     */
+    public abstract class KBAgent : AbstractAgent
+    {
+	// persistent: KB, a knowledge base
+	protected KnowledgeBase KB;
+	// t, a counter, initially 0, indicating time
+	private int t = 0;
+
+	public KBAgent(KnowledgeBase KB)
+	{
+	    this.KB = KB;
+	}
+
+	// function KB-AGENT(percept) returns an action
+	public override Action execute(Percept percept)
+	{
+	    // TELL(KB, MAKE-PERCEPT-SENTENCE(percept, t))
+	    KB.tell(makePerceptSentence(percept, t));
+	    // action &lt;- ASK(KB, MAKE-ACTION-QUERY(t))
+	    Action action = ask(KB, makeActionQuery(t));
+
+	    // TELL(KB, MAKE-ACTION-SENTENCE(action, t))
+	    KB.tell(makeActionSentence(action, t));
+	    // t &lt;- t + 1
+	    t = t + 1;
+	    // return action
+	    return action;
+	}
+
+	/**
+	 * MAKE-PERCEPT-SENTENCE constructs a sentence asserting that the agent
+	 * perceived the given percent at the given time.
+	 * 
+	 * @param percept
+	 *            the given percept
+	 * @param t
+	 *            the given time
+	 * @return a sentence asserting that the agent perceived the given percept
+	 *         at the given time.
+	 */
+	// MAKE-PERCEPT-SENTENCE(percept, t)
+	public abstract Sentence makePerceptSentence(Percept percept, int t);
+
+	/**
+	 * MAKE-ACTION-QUERY constructs a sentence that asks what action should be
+	 * done at the current time.
+	 * 
+	 * @param t
+	 *            the current time.
+	 * @return a sentence that asks what action should be done at the current
+	 *         time.
+	 */
+	// MAKE-ACTION-QUERY(t)
+	public abstract Sentence makeActionQuery(int t);
+
+	/**
+	 * MAKE-ACTION-SENTENCE constructs a sentence asserting that the chosen action was executed.
+	 * @param action
+	 *        the chose action.
+	 * @param t
+	 *        the time at which the action was executed.
+	 * @return a sentence asserting that the chosen action was executed.
+	 */
+	// MAKE-ACTION-SENTENCE(action, t)
+	public abstract Sentence makeActionSentence(Action action, int t);
+
+	/**
+	 * A wrapper around the KB's ask() method which translates the action (in the form of
+	 * a sentence) determined by the KB into an allowed 'Action' object from the current
+	 * environment in which the KB-AGENT resides.
+	 * 
+	 * @param KB
+	 *        the KB to ask.
+	 * @param actionQuery
+	 *        an action query.
+	 * @return the Action to be performed in response to the given query.
+	 */
+	// ASK(KB, MAKE-ACTION-QUERY(t))
+	public abstract Action ask(KnowledgeBase KB, Sentence actionQuery);
+    }
+}