1 files changed, 177 insertions, 0 deletions
diff --git a/BJC-Utils2/src/main/java/bjc/utils/gen/WeightedGrammar.java b/BJC-Utils2/src/main/java/bjc/utils/gen/WeightedGrammar.java
new file mode 100644
index 0000000..8733723
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/gen/WeightedGrammar.java
@@ -0,0 +1,177 @@
+package bjc.utils.gen;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Random;
+import java.util.function.Function;
+
+import bjc.utils.funcdata.FunctionalList;
+
+/**
+ * A random grammar, where certain rules will come up morre often than
+ * others.
+ * 
+ * @author ben
+ *
+ * @param <E> The values that make up sentances of this grammar.
+ */
+public class WeightedGrammar<E> {
+	protected Map<E, WeightedRandom<FunctionalList<E>>>	rules;
+	protected Map<E, WeightedGrammar<E>>				subgrammars;
+	private Random sr;
+
+	/**
+	 * Create a new weighted grammar that uses the specified source of randomness.
+	 */
+	public WeightedGrammar(Random src) {
+		this();
+		sr = src;
+	}
+	
+	/**
+	 * Create a new weighted grammar.
+	 */
+	public WeightedGrammar() {
+		rules = new HashMap<>();
+	}
+
+	/**
+	 * Add a case to an already existing rule.
+	 * 
+	 * @param rule The rule to add a case to.
+	 * @param prob The probability for this rule to be chosen.
+	 * @param cse The case being added.
+	 */
+	public void addCase(E rule, int prob, FunctionalList<E> cse) {
+		WeightedRandom<FunctionalList<E>> rn = rules.get(rule);
+
+		rn.addProb(prob, cse);
+	}
+
+	/**
+	 * Add a new rule with no cases.
+	 * @param name The name of the rule to add.
+	 * @return Whether or not the rule was succesfully added.
+	 */
+	public boolean addRule(E name) {
+		if(sr == null) {
+			sr = new Random();
+		}
+		return addRule(name, new WeightedRandom<>(sr));
+	}
+
+	/**
+	 * Add a new rule with a set of cases.
+	 * @param name The name of the rule to add.
+	 * @param rnd The set of cases for the rule.
+	 * @return Whether or not the rule was succesfully added.
+	 */
+	public boolean addRule(E name, WeightedRandom<FunctionalList<E>> rnd) {
+		if (rules.containsKey(name)) {
+			return false;
+		} else {
+			rules.put(name, rnd);
+			return true;
+		}
+	}
+
+	/**
+	 * Add a subgrammar.
+	 * @param name The name of the subgrammar.
+	 * @param subG The subgrammar to add.
+	 * @return Whether or not the subgrammar was succesfully added.
+	 */
+	public boolean addSubGrammar(E name, WeightedGrammar<E> subG) {
+		if (subgrammars.containsKey(name)) {
+			return false;
+		} else {
+			subgrammars.put(name, subG);
+			return true;
+		}
+	}
+
+	/**
+	 * Generate a set of debug sentences for the specified rule.
+	 * 		Only generates sentances one layer deep.
+	 * @param rl The rule to test.
+	 * @return A set of sentances generated by the specified rule.
+	 */
+	public FunctionalList<FunctionalList<E>> debugVals(E rl) {
+		FunctionalList<FunctionalList<E>> fl = new FunctionalList<>();
+
+		WeightedRandom<FunctionalList<E>> random = rules.get(rl);
+
+		for (int i = 0; i < 10; i++) {
+			fl.add(random.genVal());
+		}
+
+		return fl;
+	}
+
+	/**
+	 * Generate a generic sentance from a initial rule.
+	 * 
+	 * @param initRule The initial rule to start with.
+	 * @param f The function to transform grammar output into something.
+	 * @param spacer The spacer element to add in between output tokens.
+	 * @return A randomly generated sentance from the specified initial rule.
+	 */
+	public <T> FunctionalList<T> genGeneric(E initRule, Function<E, T> f,
+			T spacer) {
+		FunctionalList<T> r = new FunctionalList<>();
+
+		if (subgrammars.containsKey(initRule)) {
+			subgrammars.get(initRule).genGeneric(initRule, f, spacer)
+					.forEach(rp -> {
+						r.add(rp);
+						r.add(spacer);
+					});
+		} else if (rules.containsKey(initRule)) {
+			rules.get(initRule).genVal().forEach(
+					rp -> genGeneric(rp, f, spacer).forEach(rp2 -> {
+						r.add(rp2);
+						r.add(spacer);
+					}));
+		} else {
+			r.add(f.apply(initRule));
+			r.add(spacer);
+		}
+
+		return r;
+	}
+
+	/**
+	 * Generate a random list of grammar elements from a given initial rule.
+	 * @param initRule The initial rule to start with.
+	 * @param spacer The item to use to space the list.
+	 * @return A list of random grammar elements generated by the specified rule.
+	 */
+	public FunctionalList<E> genList(E initRule, E spacer) {
+		return genGeneric(initRule, s -> s, spacer);
+	}
+
+	/**
+	 * Get the subgrammar with the specified name.
+	 * @param name The name of the subgrammar to get.
+	 * @return The subgrammar with the specified name.
+	 */
+	public WeightedGrammar<E> getSubGrammar(E name) {
+		return subgrammars.get(name);
+	}
+
+	/**
+	 * Remove a rule with the specified name.
+	 * @param name The name of the rule to remove.
+	 */
+	public void removeRule(E name) {
+		rules.remove(name);
+	}
+
+	/**
+	 * Remove a subgrammar with the specified name.
+	 * @param name The name of the subgrammar to remove.
+	 */
+	public void removeSubgrammar(E name) {
+		subgrammars.remove(name);
+	}
+}