remove redundant interfaces and generalize shift/reset generics

Turns out Function can do the jobs of both CallbackReceiver and
FunctionReceiver, so I've removed the latter two.

Also, shift and reset should work with a combination of types, not
just a single type, so I've expanded their generic signatures.

classpath/avian/CallbackReceiver.java

@@ -1,15 +0,0 @@
-/* Copyright (c) 2008-2013, Avian Contributors
-
-   Permission to use, copy, modify, and/or distribute this software
-   for any purpose with or without fee is hereby granted, provided
-   that the above copyright notice and this permission notice appear
-   in all copies.
-
-   There is NO WARRANTY for this software.  See license.txt for
-   details. */
-
-package avian;
-
-public interface CallbackReceiver<T> {
-  public T receive(Callback<T> callback) throws Exception;
-}

classpath/avian/Continuations.java

@@ -127,14 +127,14 @@ public class Continuations {
    * specified receiver.
    *
    * <p>This method will either return the result returned by
-   * <code>receiver.receive(Callback)</code>, propagate the exception
+   * <code>receiver.call(Callback)</code>, propagate the exception
    * thrown by that method, return the result passed to the
    * handleResult(T) method of the continuation, or throw the
    * exception passed to the handleException(Throwable) method of the
    * continuation.
    */
   public static native <T> T callWithCurrentContinuation
-    (CallbackReceiver<T> receiver) throws Exception;
+    (Function<Callback<T>,T> receiver) throws Exception;
 
   /**
    * Calls the specified "before" and "after" tasks each time a
@@ -183,13 +183,13 @@ public class Continuations {
     }
   }
 
-  public static <T> T reset(final Callable<T> thunk) throws Exception {
+  public static <B,C> C reset(final Callable<B> thunk) throws Exception {
     final Reset reset = new Reset(latestReset.get());
     latestReset.set(reset);
     try {
-      T result = callWithCurrentContinuation
+      C result = (C) callWithCurrentContinuation
-        (new CallbackReceiver<T>() {
+        (new Function<Callback<Object>,Object>() {
-          public T receive(Callback<T> continuation) throws Exception {
+          public Object call(Callback continuation) throws Exception {
             reset.continuation = continuation;
             return thunk.call();
           }
@@ -207,26 +207,26 @@ public class Continuations {
     }
   }
 
-  public static <T> T shift
+  public static <A,B,C> A shift
-    (final FunctionReceiver<T> receiver)
+    (final Function<Function<A,B>,C> receiver)
     throws Exception
   {
-    return (T) callWithCurrentContinuation(new CallbackReceiver() {
+    return (A) callWithCurrentContinuation
-        public Object receive(final Callback continuation) {
+      (new Function<Callback<Object>,Object>() {
+        public Object call(final Callback continuation) {
           final Reset reset = latestReset.get();
           reset.shifts = new Cell(new Callback() {
               public void handleResult(Object ignored) {
                 try {
                   reset.continuation.handleResult
-                    (receiver.receive
+                    (receiver.call
                      (new Function() {
                          public Object call(final Object argument)
                            throws Exception
                          {
                            return callWithCurrentContinuation
-                             (new CallbackReceiver() {
+                             (new Function<Callback<Object>,Object>() {
-                                 public Object receive
+                                 public Object call(Callback shiftContinuation)
-                                   (Callback shiftContinuation)
                                    throws Exception
                                  {
                                    reset.shifts = new Cell

classpath/avian/Function.java

@@ -10,6 +10,6 @@
 
 package avian;
 
-public interface Function<T> {
+public interface Function<A,B> {
-  public T call(T argument) throws Exception;
+  public B call(A argument) throws Exception;
 }

classpath/avian/FunctionReceiver.java

@@ -1,15 +0,0 @@
-/* Copyright (c) 2008-2013, Avian Contributors
-
-   Permission to use, copy, modify, and/or distribute this software
-   for any purpose with or without fee is hereby granted, provided
-   that the above copyright notice and this permission notice appear
-   in all copies.
-
-   There is NO WARRANTY for this software.  See license.txt for
-   details. */
-
-package avian;
-
-public interface FunctionReceiver<T> {
-  public T receive(Function<T> function) throws Exception;
-}

src/compile.cpp

@@ -8044,8 +8044,8 @@ callWithCurrentContinuation(MyThread* t, object receiver)
 
     if (root(t, ReceiveMethod) == 0) {
       object m = resolveMethod
-        (t, root(t, Machine::BootLoader), "avian/CallbackReceiver", "receive",
+        (t, root(t, Machine::BootLoader), "avian/Function", "call",
-         "(Lavian/Callback;)Ljava/lang/Object;");
+         "(Ljava/lang/Object;)Ljava/lang/Object;");
 
       if (m) {
         setRoot(t, ReceiveMethod, m);

src/types.def

@@ -176,8 +176,6 @@
 
 (type unwindResult avian/Continuations$UnwindResult)
 
-(type callbackReceiver avian/CallbackReceiver)
-
 (type string java/lang/String
   (alias data object value)
   (alias length uint32_t count)

test/extra/ComposableContinuations.java

@@ -1,10 +1,9 @@
 package extra;
 
 import static avian.Continuations.shift;
-import static avian.Continuations.reset;
 
-import avian.FunctionReceiver;
 import avian.Function;
+import avian.Continuations;
 
 import java.util.concurrent.Callable;
 
@@ -14,10 +13,11 @@ public class ComposableContinuations {
   }
 
   public static void main(String[] args) throws Exception {
-    expect(2 * reset(new Callable<Integer>() {
+    expect(2 * Continuations.<Integer,Integer>reset(new Callable<Integer>() {
           public Integer call() throws Exception {
-            return 1 + shift(new FunctionReceiver<Integer>() {
+            return 1 + shift
-                public Integer receive(Function<Integer> continuation)
+              (new Function<Function<Integer,Integer>,Integer>() {
+                public Integer call(Function<Integer,Integer> continuation)
                   throws Exception
                 {
                   return continuation.call(5);
@@ -26,10 +26,11 @@ public class ComposableContinuations {
           }
         }) == 12);
 
-    expect(1 + reset(new Callable<Integer>() {
+    expect(1 + Continuations.<Integer,Integer>reset(new Callable<Integer>() {
           public Integer call() throws Exception {
-            return 2 * shift(new FunctionReceiver<Integer>() {
+            return 2 * shift
-                public Integer receive(Function<Integer> continuation)
+              (new Function<Function<Integer,Integer>,Integer>() {
+                public Integer call(Function<Integer,Integer> continuation)
                   throws Exception
                 {
                   return continuation.call(continuation.call(4));
@@ -38,29 +39,53 @@ public class ComposableContinuations {
           }
         }) == 17);
 
-    expect(equal(reset(new Callable<Cell<Integer>>() {
+    expect
-            public Cell<Integer> call() throws Exception {
+      (equal
-              shift(new FunctionReceiver<Cell<Integer>>() {
+       (Continuations.<Cell<Integer>,Cell<Integer>>reset
-                  public Cell<Integer> receive
+        (new Callable<Cell<Integer>>() {
-                    (Function<Cell<Integer>> continuation)
+          public Cell<Integer> call() throws Exception {
+            shift(new Function<Function<Cell<Integer>,Cell<Integer>>,
+                  Cell<Integer>>()
+                  {
+                    public Cell<Integer> call
+                      (Function<Cell<Integer>,Cell<Integer>> continuation)
+                      throws Exception
+                    {
+                      return cons(1, continuation.call(null));
+                    }
+                  });
+
+            shift(new Function<Function<Cell<Integer>,Cell<Integer>>,
+                  Cell<Integer>>()
+                  {
+                    public Cell<Integer> call
+                      (Function<Cell<Integer>,Cell<Integer>> continuation)
+                      throws Exception
+                    {
+                      return cons(2, continuation.call(null));
+                    }
+                  });
+
+            return null;
+          }
+        }), cons(1, cons(2, null))));
+
+    expect
+      (equal
+       (Continuations.<String,Integer>reset
+        (new Callable<String>() {
+          public String call() throws Exception {
+            return new String
+              (shift(new Function<Function<byte[],String>,Integer>() {
+                  public Integer call(Function<byte[],String> continuation)
                     throws Exception
                   {
-                    return cons(1, continuation.call(null));
+                    return Integer.parseInt
+                      (continuation.call(new byte[] { 0x34, 0x32 }));
                   }
-                });
+                }), "UTF-8");
-
+          }
-              shift(new FunctionReceiver<Cell<Integer>>() {
+        }), 42));
-                  public Cell<Integer> receive
-                    (Function<Cell<Integer>> continuation)
-                    throws Exception
-                  {
-                    return cons(2, continuation.call(null));
-                  }
-                });
-
-              return null;
-            }
-          }), cons(1, cons(2, null))));
   }
 
   private static <T> boolean equal(T a, T b) {

test/extra/Continuations.java

@@ -2,7 +2,7 @@ package extra;
 
 import static avian.Continuations.callWithCurrentContinuation;
 
-import avian.CallbackReceiver;
+import avian.Function;
 import avian.Callback;
 
 public class Continuations {
@@ -11,22 +11,26 @@ public class Continuations {
   }
 
   public static void main(String[] args) throws Exception {
-    expect(callWithCurrentContinuation(new CallbackReceiver<Integer>() {
+    expect
-          public Integer receive(Callback<Integer> continuation) {
+      (callWithCurrentContinuation
-            continuation.handleResult(42);
+       (new Function<Callback<Integer>,Integer>() {
-            throw new AssertionError();
+         public Integer call(Callback<Integer> continuation) {
-          }
+           continuation.handleResult(42);
-        }) == 42);
+           throw new AssertionError();
+         }
+       }) == 42);
 
-    expect(callWithCurrentContinuation(new CallbackReceiver<Integer>() {
+    expect
-          public Integer receive(Callback<Integer> continuation) {
+      (callWithCurrentContinuation
-            return 43;
+       (new Function<Callback<Integer>,Integer>() {
-          }
+         public Integer call(Callback<Integer> continuation) {
-        }) == 43);
+           return 43;
+         }
+       }) == 43);
 
     try {
-      callWithCurrentContinuation(new CallbackReceiver<Integer>() {
+      callWithCurrentContinuation(new Function<Callback<Integer>,Integer>() {
-          public Integer receive(Callback<Integer> continuation) {
+          public Integer call(Callback<Integer> continuation) {
             continuation.handleException(new MyException());
             throw new AssertionError();
           }
@@ -37,8 +41,8 @@ public class Continuations {
     }
 
     try {
-      callWithCurrentContinuation(new CallbackReceiver<Integer>() {
+      callWithCurrentContinuation(new Function<Callback<Integer>,Integer>() {
-          public Integer receive(Callback<Integer> continuation)
+          public Integer call(Callback<Integer> continuation)
             throws MyException
           {
             throw new MyException();

test/extra/Coroutines.java

@@ -2,7 +2,7 @@ package extra;
 
 import static avian.Continuations.callWithCurrentContinuation;
 
-import avian.CallbackReceiver;
+import avian.Function;
 import avian.Callback;
 
 public class Coroutines {
@@ -40,8 +40,8 @@ public class Coroutines {
 
     final Consumer<Character> consumer = new Consumer<Character>() {
       public void consume(final Character c) throws Exception {
-        callWithCurrentContinuation(new CallbackReceiver() {
+        callWithCurrentContinuation(new Function<Callback<Object>,Object>() {
-          public Object receive(Callback continuation) {
+          public Object call(Callback continuation) {
             state.produceNext = continuation;
 
             state.consumeNext.handleResult(c);
@@ -53,9 +53,9 @@ public class Coroutines {
     };
 
     final Producer<Character> producer = new Producer<Character>() {
-      final CallbackReceiver<Character> receiver
+      final Function<Callback<Character>,Character> receiver
-      = new CallbackReceiver<Character>() {
+      = new Function<Callback<Character>,Character>() {
-        public Character receive(Callback<Character> continuation)
+        public Character call(Callback<Character> continuation)
         throws Exception
         {
           state.consumeNext = continuation;

test/extra/DynamicWind.java

@@ -3,7 +3,7 @@ package extra;
 import static avian.Continuations.callWithCurrentContinuation;
 import static avian.Continuations.dynamicWind;
 
-import avian.CallbackReceiver;
+import avian.Function;
 import avian.Callback;
 
 import java.util.concurrent.Callable;
@@ -86,24 +86,27 @@ public class DynamicWind {
       });
   }
 
-  private void continuationUnwindTest(final CallbackReceiver<Integer> receiver)
+  private void continuationUnwindTest
+    (final Function<Callback<Integer>,Integer> receiver)
     throws Exception
   {
     System.out.println("continuationUnwindTest enter");
             
     try {
-      expect(callWithCurrentContinuation(new CallbackReceiver<Integer>() {
+      expect
-            public Integer receive(final Callback<Integer> continuation)
+        (callWithCurrentContinuation
-              throws Exception
+         (new Function<Callback<Integer>,Integer>() {
-            {
+           public Integer call(final Callback<Integer> continuation)
-              unwindTest(new Callable<Integer>() {
+             throws Exception
-                  public Integer call() throws Exception {
+           {
-                    return receiver.receive(continuation);
+             unwindTest(new Callable<Integer>() {
-                  }
+                 public Integer call() throws Exception {
-                });
+                   return receiver.call(continuation);
-              throw new AssertionError();
+                 }
-            }
+               });
-          }) == 42);
+             throw new AssertionError();
+           }
+         }) == 42);
     } catch (MyException e) {
       e.printStackTrace();
     }
@@ -118,8 +121,8 @@ public class DynamicWind {
   }
 
   private void continuationResultUnwind() throws Exception {
-    continuationUnwindTest(new CallbackReceiver<Integer>() {
+    continuationUnwindTest(new Function<Callback<Integer>,Integer>() {
-          public Integer receive(final Callback<Integer> continuation) {
+          public Integer call(final Callback<Integer> continuation) {
             continuation.handleResult(42);
             throw new AssertionError();
           }
@@ -127,8 +130,8 @@ public class DynamicWind {
   }
 
   private void continuationExceptionUnwind() throws Exception {
-    continuationUnwindTest(new CallbackReceiver<Integer>() {
+    continuationUnwindTest(new Function<Callback<Integer>,Integer>() {
-          public Integer receive(final Callback<Integer> continuation) {
+          public Integer call(final Callback<Integer> continuation) {
             continuation.handleException(new MyException());
             throw new AssertionError();
           }
@@ -163,8 +166,8 @@ public class DynamicWind {
             task = 1;
         
             return callWithCurrentContinuation
-            (new CallbackReceiver<Integer>() {
+            (new Function<Callback<Integer>,Integer>() {
-              public Integer receive(final Callback<Integer> continuation)
+              public Integer call(final Callback<Integer> continuation)
                 throws Exception
               {
                 continuationReference = continuation;