consolidate duplicate Cell classes

classpath/avian/Cell.java

@@ -31,4 +31,24 @@ public class Cell <T> {
     sb.append(")");
     return sb.toString();
   }
+
+  public static <Car> Cell<Car> cons(Car car, Cell<Car> cdr) {
+    return new Cell(car, cdr);
+  }
+
+  public static <T> boolean equal(T a, T b) {
+    return (a == null && b == null) || (a != null && a.equals(b));
+  }
+  
+  public static <Car> boolean equal(Cell<Car> a, Cell<Car> b) {
+    while (a != null) {
+      if (b == null || (! equal(a.value, b.value))) {
+        return false;
+      }
+      a = a.next;
+      b = b.next;
+    }
+
+    return b == null;
+  }
 }

classpath/avian/Continuations.java

@@ -324,14 +324,4 @@ public class Continuations {
       this.next = next;
     }
   }
-
-  private static class Cell<T> {
-    public final T value;
-    public final Cell<T> next;
-
-    public Cell(T value, Cell<T> next) {
-      this.value = value;
-      this.next = next;
-    }
-  }
 }

test/extra/ComposableContinuations.java

@@ -1,7 +1,10 @@
 package extra;
 
 import static avian.Continuations.shift;
+import static avian.Cell.cons;
+import static avian.Cell.equal;
 
+import avian.Cell;
 import avian.Function;
 import avian.Continuations;
 
@@ -87,47 +90,4 @@ public class ComposableContinuations {
           }
         }), 42));
   }
-
-  private static <T> boolean equal(T a, T b) {
-    return (a == null && b == null) || (a != null && a.equals(b));
-  }
-  
-  private static <Car> boolean equal(Cell<Car> a, Cell<Car> b) {
-    while (a != null) {
-      if (b == null || (! equal(a.car, b.car))) {
-        return false;
-      }
-      a = a.cdr;
-      b = b.cdr;
-    }
-
-    return b == null;
-  }
-
-  private static <Car> Cell<Car> cons(Car car, Cell<Car> cdr) {
-    return new Cell(car, cdr);
-  }
-
-  private static class Cell<Car> {
-    public final Car car;
-    public final Cell<Car> cdr;
-
-    public Cell(Car car, Cell<Car> cdr) {
-      this.car = car;
-      this.cdr = cdr;
-    }
-
-    public String toString() {
-      StringBuilder sb = new StringBuilder();
-      sb.append("(");
-      for (Cell<Car> c = this; c != null; c = c.cdr) {
-        sb.append(c.car);
-        if (c.cdr != null) {
-          sb.append(", ");
-        }
-      }
-      sb.append(")");
-      return sb.toString();
-    }
-  }
 }