Github user viirya commented on a diff in the pull request:
https://github.com/apache/spark/pull/15718#discussion_r86301490
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypeCreator.scala
---
@@ -172,110 +174,80 @@ case class CreateMap(children: Seq[Expression])
extends Expression {
}
/**
- * Returns a Row containing the evaluation of all children expressions.
+ * An expression representing a not yet available attribute name. This
expression is unevaluable
+ * and as its name suggests it is a temporary place holder until we're
able to determine the
+ * actual attribute name.
*/
-@ExpressionDescription(
- usage = "_FUNC_(col1, col2, col3, ...) - Creates a struct with the given
field values.")
-case class CreateStruct(children: Seq[Expression]) extends Expression {
-
- override def foldable: Boolean = children.forall(_.foldable)
-
- override lazy val dataType: StructType = {
- val fields = children.zipWithIndex.map { case (child, idx) =>
- child match {
- case ne: NamedExpression =>
- StructField(ne.name, ne.dataType, ne.nullable, ne.metadata)
- case _ =>
- StructField(s"col${idx + 1}", child.dataType, child.nullable,
Metadata.empty)
- }
- }
- StructType(fields)
- }
-
+case object NamePlaceholder extends LeafExpression with Unevaluable {
--- End diff --
@hvanhovell Although this is merged, I have a question about this
`NamePlaceholder`.
Is it necessary? Actually it has no function and will be replaced with the
field name later in analysis.
The resolution of `CreateNamedStruct` is depended on the field expressions,
actually. So if we directly use the field name, seems it is no harm too?
---
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 [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
