fix reduce

Lab8/MyTest.java

@@ -1,22 +1,13 @@
-import java.util.ArrayList;
-import java.util.List;
 
 import cs2030s.fp.InfiniteList;
 
 public class MyTest {
 
     public static void main(String[] args) {
-        List<Integer> generateHistory = new ArrayList<>();
-        List<Integer> doublerHistory = new ArrayList<>();
-        InfiniteList.generate(() -> {
-            generateHistory.add(1);
-            return 1;
-        }).map(x -> {
-            doublerHistory.add(x);
-            return x * 2;
-        }).tail().head();
-        System.out.println(generateHistory);
-        System.out.println(doublerHistory);
-        System.out.println(InfiniteList.iterate(1, x -> x + 1).filter(x -> x % 2 == 0).head());
+        InfiniteList<Integer> list = InfiniteList.iterate(1, x -> x + 1);
+        System.out.println(list.takeWhile(x -> x < 10).reduce(0, (x, y) -> {
+            System.out.println("vals: x: " + x + " y: " + y);
+            return x + y;
+        }));
     }
 }

Lab8/cs2030s/fp/InfiniteList.java

@@ -80,21 +80,20 @@ public class InfiniteList<T> {
   }
 
   public List<T> toList() {
-    List<T> arrayList = new ArrayList<>();
-    arrayList.add(this.head());
-    arrayList.addAll(this.tail().toList());
-    return arrayList;
+    return this.reduce(new ArrayList<>(), (acc, i) -> {
+      acc.add(i);
+      return acc;
+    });
   }
 
   public <U> U reduce(U id, Combiner<U, U, ? super T> acc) {
-    // reduce by applying this.head to acc, this.tail.head to acc,
-    // this.tail.tail.head to acc, until finally id to acc
-    // return acc.combine(this., acc)
-    return null;
+    return this.head.get().transform((h) -> this.tail.get().reduce(acc.combine(id, this.head.get().unless(null)), acc))
+        .except(() -> this.tail.get().reduce(id, acc));
+
   }
 
   public long count() {
-    return this.reduce(0L, (a, b) -> a + 1);
+    return this.reduce(0L, (a, b) -> a + 1L);
   }
 
   @Override