Added handling of .Data slot for S4 objects.

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/access/UpdateSlotNode.java

@@ -17,7 +17,10 @@ import com.oracle.truffle.api.dsl.*;
 import com.oracle.truffle.r.nodes.attributes.PutAttributeNode;
 import com.oracle.truffle.r.nodes.attributes.PutAttributeNodeGen;
 import com.oracle.truffle.r.nodes.function.ClassHierarchyNode;
+import com.oracle.truffle.r.runtime.RRuntime;
+import com.oracle.truffle.r.runtime.context.RContext;
 import com.oracle.truffle.r.runtime.data.*;
+import com.oracle.truffle.r.runtime.env.REnvironment;
 import com.oracle.truffle.r.runtime.nodes.*;
 
 @NodeChildren({@NodeChild(value = "object", type = RNode.class), @NodeChild(value = "name", type = RNode.class), @NodeChild(value = "value", type = RNode.class)})
@@ -34,17 +37,39 @@ public abstract class UpdateSlotNode extends RNode {
     }
 
     @SuppressWarnings("unused")
-    @Specialization(guards = "name == cachedName")
+    @Specialization(guards = {"!isData(name)", "name == cachedName"})
     protected Object updateSlotS4Cached(RAttributable object, String name, Object value, @Cached("name") String cachedName, @Cached("createAttrUpdate(cachedName)") PutAttributeNode attributeUpdate) {
         attributeUpdate.execute(object.initAttributes(), value);
         return object;
     }
 
-    @Specialization(contains = "updateSlotS4Cached")
+    @Specialization(contains = "updateSlotS4Cached", guards = "!isData(name)")
     protected Object updateSlotS4(RAttributable object, String name, Object value) {
         assert name == name.intern();
         object.setAttr(name, value);
         return object;
     }
 
+    protected RFunction setDataPartFunction(REnvironment methodsNamespace) {
+        Object f = methodsNamespace.findFunction("setDataPart");
+        return (RFunction) RContext.getRRuntimeASTAccess().forcePromise(f);
+    }
+
+    private Object setDataPart(RAttributable object, Object value) {
+        // TODO: any way to cache it or use a mechanism similar to overrides?
+        REnvironment methodsNamespace = REnvironment.getRegisteredNamespace("methods");
+        RFunction dataPart = setDataPartFunction(methodsNamespace);
+        return RContext.getEngine().evalFunction(dataPart, methodsNamespace.getFrame(), object, value, RRuntime.LOGICAL_TRUE);
+    }
+
+    @Specialization(guards = "isData(name)")
+    protected Object updateSlotS4Data(RAttributable object, @SuppressWarnings("unused") String name, Object value) {
+        return setDataPart(object, value);
+    }
+
+    protected boolean isData(String name) {
+        assert name == name.intern();
+        return name == RRuntime.DOT_DATA;
+    }
+
 }