Implement a tentative pattern class that can be compiled from a string.

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

@@ -0,0 +1,40 @@
+package org.nwapw.abacus.lexing.pattern;
+
+public class PatternChain<T> {
+
+    public PatternNode<T> head;
+    public PatternNode<T> tail;
+
+    public PatternChain(PatternNode<T> head, PatternNode<T> tail){
+        this.head = head;
+        this.tail = tail;
+    }
+
+    public PatternChain(PatternNode<T> node){
+        this(node, node);
+    }
+
+    public PatternChain(){
+        this(null);
+    }
+
+    public void append(PatternChain<T> other){
+        if(other.head == null || tail == null) {
+            this.head = other.head;
+            this.tail = other.tail;
+        } else {
+            tail.outputStates.add(other.head);
+            tail = other.tail;
+        }
+    }
+
+    public void append(PatternNode<T> node){
+        if(tail == null){
+            head = tail = node;
+        } else {
+            tail.outputStates.add(node);
+            tail = node;
+        }
+    }
+
+}