Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/2319#discussion_r88684517
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/expressions/composite.scala
---
@@ -0,0 +1,88 @@
+/*
+ * 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.flink.api.table.expressions
+
+import org.apache.calcite.rex.RexNode
+import org.apache.calcite.tools.RelBuilder
+import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.api.common.typeutils.CompositeType
+import org.apache.flink.api.table.UnresolvedException
+import org.apache.flink.api.table.validate.{ExprValidationResult,
ValidationFailure, ValidationSuccess}
+
+
+case class Flattening(child: Expression) extends UnaryExpression {
+
+ override def toString = s"$child.flatten()"
+
+ override private[flink] def resultType: TypeInformation[_] =
+ throw UnresolvedException(s"Invalid call to on ${this.getClass}.")
+
+ override private[flink] def validateInput(): ExprValidationResult =
+ ValidationFailure(s"Unresolved flattening of $child")
+}
+
+case class GetCompositeField(child: Expression, key: Any) extends
UnaryExpression {
+
+ private var fieldIndex: Option[Int] = None
+
+ override def toString = s"$child.get($key)"
+
+ override private[flink] def validateInput(): ExprValidationResult = {
--- End diff --
Don't we need to recursively check if `child` is valid as well? Could be
the result of an expression, right?
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
