Import cql3 package and sub-packages

Contains the cql3 grammer and supporting classes, which will be converted
one by one.

From commit bf599fb5b062cbcc652da78b7d699e7a01b949ad.

cql3/functions/NativeFunction.java

@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.cassandra.cql3.functions;
+
+import java.util.Arrays;
+
+import org.apache.cassandra.db.marshal.AbstractType;
+
+/**
+ * Base class for our native/hardcoded functions.
+ */
+public abstract class NativeFunction extends AbstractFunction
+{
+    protected NativeFunction(String name, AbstractType<?> returnType, AbstractType<?>... argTypes)
+    {
+        super(FunctionName.nativeFunction(name), Arrays.asList(argTypes), returnType);
+    }
+
+    // Most of our functions are pure, the other ones should override this
+    public boolean isPure()
+    {
+        return true;
+    }
+
+    public boolean isNative()
+    {
+        return true;
+    }
+}