more wip

jnape · jnape · commit 51646db683e1 · 2017-01-27T21:20:20.000-06:00
diff --git a/src/main/java/com/jnape/palatable/lambda/recursionschemes/builtin/Anamorphism.java b/src/main/java/com/jnape/palatable/lambda/recursionschemes/builtin/Anamorphism.java
@@ -7,7 +7,7 @@
 import com.jnape.palatable.lambda.recursionschemes.Thunk;
 import fix.Coalgebra;
 
-import static com.jnape.palatable.lambda.recursionschemes.builtin.Hylomorphism.hylo;
+import static com.jnape.palatable.lambda.recursionschemes.Fix.fix;
 
 public final class Anamorphism<A, F extends Functor, FA extends Functor<A, F>> implements Fn2<Coalgebra<A, FA>, A, Fix<F, Functor<Fix<F, ?>, F>>> {
 
@@ -18,12 +18,7 @@ private Anamorphism() {
 
     @Override
     public Fix<F, Functor<Fix<F, ?>, F>> apply(Coalgebra<A, FA> coalgebra, A a) {
-        return hylo(f -> () -> new Thunk<>(() -> {
-            f.fmap(fixed -> coalgebra.apply(fixed.unfix()))
-            FA apply = coalgebra.apply(a);
-            return apply;
-        }).<Fix<F, ?>>fmap(a1 -> ana(coalgebra, a1)).get(), coalgebra, a);
-
+        return fix(new Thunk<>(() -> coalgebra.apply(a)).<Fix<F, ?>>fmap(ana(coalgebra)).get());
     }
 
     @SuppressWarnings("unchecked")
diff --git a/src/main/java/com/jnape/palatable/lambda/recursionschemes/builtin/Hylomorphism.java b/src/main/java/com/jnape/palatable/lambda/recursionschemes/builtin/Hylomorphism.java
@@ -5,16 +5,20 @@
 import com.jnape.palatable.lambda.functions.Fn3;
 import com.jnape.palatable.lambda.functor.Functor;
 import com.jnape.palatable.lambda.recursionschemes.Algebra;
+import com.jnape.palatable.lambda.recursionschemes.Thunk;
 import fix.Coalgebra;
 
+import static com.jnape.palatable.lambda.recursionschemes.builtin.Anamorphism.ana;
+import static com.jnape.palatable.lambda.recursionschemes.builtin.Catamorphism.cata;
+
 public final class Hylomorphism<A, B, F extends Functor, FA extends Functor<A, F>, FB extends Functor<B, F>> implements Fn3<Algebra<FB, B>, Coalgebra<A, FA>, A, B> {
 
     private static final Hylomorphism INSTANCE = new Hylomorphism();
 
     private Hylomorphism() {
     }
 
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({"unchecked", "Duplicates"})
     public A fapply(Algebra<FA, A> algebra, Coalgebra<A, FA> coalgebra, A a) {
         A x = a;
         FA fa = coalgebra.apply(x);
@@ -28,15 +32,28 @@ public A fapply(Algebra<FA, A> algebra, Coalgebra<A, FA> coalgebra, A a) {
         }
 
         return x;
-//
-//        return algebra.apply((FB) coalgebra.apply(a).fmap(hylo(algebra, coalgebra)));
-//        return cata(algebra).compose(ana(coalgebra)).apply(a);
     }
 
+    @SuppressWarnings({"unchecked", "Duplicates"})
+    public B fapply2(Algebra<FB, B> algebra, Coalgebra<A, FA> coalgebra, A a) {
+        A x = a;
+        B currentB = null;
+        FA fa = coalgebra.apply(x);
+        FA previous = null;
+        while (fa != previous) {
+            previous = fa;
+            final FA foo = fa;
+            Thunk<B, F> bfThunk = new Thunk<>(() -> foo.fmap(a1 -> fapply2(algebra, coalgebra, a1)));
+            currentB = algebra.apply((FB) bfThunk.get());
+        }
+        return currentB;
+    }
+
+
     @Override
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({"unchecked", "Duplicates"})
     public B apply(Algebra<FB, B> algebra, Coalgebra<A, FA> coalgebra, A a) {
-        return algebra.apply((FB) coalgebra.apply(a).fmap(hylo(algebra, coalgebra)));
+        return cata(algebra).compose(ana(coalgebra)).apply(a);
     }
 
     @SuppressWarnings("unchecked")
diff --git a/src/test/java/com/jnape/palatable/lambda/recursionschemes/builtin/AnamorphismTest.java b/src/test/java/com/jnape/palatable/lambda/recursionschemes/builtin/AnamorphismTest.java
@@ -25,15 +25,12 @@ public void unfoldingToGreatestFixedPoint() {
                      ana(elements, 0));
     }
 
-    @Test
+    //    @Test
+    //todo: wip
     public void unfoldingInfiniteCodata() {
-        Coalgebra<Integer, NatF<Integer>> naturals = i -> {
-            if (i % 10000 == 0)
-                System.out.println("i = " + i);
-            return NatF.s(i + 1);
-        };
-        Algebra<NatF<Integer>, Integer> sum = nat -> nat.match(z -> 0, s -> s.carrier() + 1);
-        Integer x = Hylomorphism.<Integer, Integer, NatF, NatF<Integer>, NatF<Integer>>hylo().fapply(sum, naturals, 0);
+        Coalgebra<Integer, NatF<Integer>> naturals = i -> NatF.s(i + 1);
+        Algebra<NatF<String>, String> sum = nat -> nat.match(z -> "0", s -> s.carrier() + 1);
+        String x = Hylomorphism.<Integer, String, NatF, NatF<Integer>, NatF<String>>hylo().apply(sum, naturals, 0);
         System.out.println(x);
 
     }
