Implement a few nodes for the pattern matching.

src/org/nwapw/abacus/lexing/pattern/PatternNode.java

@@ -0,0 +1,25 @@
+package org.nwapw.abacus.lexing.pattern;
+
+import java.util.ArrayList;
+
+public class PatternNode<T> {
+
+    protected ArrayList<PatternNode<T>> outputStates;
+
+    public PatternNode(){
+        outputStates = new ArrayList<>();
+    }
+
+    public boolean matches(char other){
+        return false;
+    }
+
+    public char range(){
+        return '\0';
+    }
+
+    public void addInto(ArrayList<PatternNode<T>> into){
+        into.add(this);
+    }
+
+}