set add support for __reduce__

Author: cosminbasca

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/common/HashingStorage.java

@@ -234,8 +234,25 @@ public void addAll(HashingStorage other, Equivalence eq) {
 
     public abstract Iterable<Object> keys();
 
+    private Object[] iteratorAsArray(Iterable<Object> iterable) {
+        Object[] items = new Object[this.length()];
+        int i = 0;
+        for(Object item: iterable) {
+            items[i++] = item;
+        }
+        return items;
+    }
+
+    public Object[] keysAsArray() {
+        return iteratorAsArray(keys());
+    }
+
     public abstract Iterable<Object> values();
 
+    public Object[] valuesAsArray() {
+        return iteratorAsArray(values());
+    }
+
     public abstract Iterable<DictEntry> entries();
 
     public abstract void clear();

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/set/FrozenSetBuiltins.java

@@ -34,6 +34,7 @@
 import static com.oracle.graal.python.nodes.SpecialMethodNames.__LEN__;
 import static com.oracle.graal.python.nodes.SpecialMethodNames.__LE__;
 import static com.oracle.graal.python.nodes.SpecialMethodNames.__LT__;
+import static com.oracle.graal.python.nodes.SpecialMethodNames.__REDUCE__;
 import static com.oracle.graal.python.nodes.SpecialMethodNames.__SUB__;
 
 import java.util.List;
@@ -94,6 +95,18 @@ public int len(PBaseSet self) {
         }
     }
 
+    @Builtin(name = __REDUCE__, fixedNumOfArguments = 1)
+    @GenerateNodeFactory
+    abstract static class ReduceNode extends PythonUnaryBuiltinNode {
+        @Specialization
+        public Object iter(PBaseSet self) {
+            Object[] reduceTuple = new Object[]{PNone.NONE, PNone.NONE, PNone.NONE};
+            reduceTuple[0] = self.getPythonClass();
+            reduceTuple[1] = factory().createTuple(new Object[]{factory().createList(self.getDictStorage().keysAsArray())});
+            return factory().createTuple(reduceTuple);
+        }
+    }
+
     @Builtin(name = __EQ__, fixedNumOfArguments = 2)
     @GenerateNodeFactory
     abstract static class EqNode extends PythonBinaryBuiltinNode {