dbtsai commented on a change in pull request #27066:
URL: https://github.com/apache/spark/pull/27066#discussion_r411912302
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypeCreator.scala
##########
@@ -514,3 +514,98 @@ case class StringToMap(text: Expression, pairDelim:
Expression, keyValueDelim: E
override def prettyName: String = "str_to_map"
}
+
+/**
+ * Adds/replaces fields in struct by name.
+ *
+ * @param children Seq(struct, name1, val1, name2, val2, ...)
+ */
+// scalastyle:off line.size.limit
+@ExpressionDescription(
+ usage = "_FUNC_(struct, name1, val1, name2, val2, ...) - Adds/replaces
fields in struct by name.",
+ examples = """
+ Examples:
+ > SELECT _FUNC_(NAMED_STRUCT("a", 1, "b", 2), "c", 3);
+ {"a":1,"b":2,"c":3}
+ > SELECT _FUNC_(NAMED_STRUCT("a", 1, "b", 2), "b", 3);
+ {"a":1,"b":3}
+ > SELECT _FUNC_(CAST(NULL AS struct<a:int,b:int>), "c", 3);
+ {"a":null,"b":null,"c":3}
+ > SELECT _FUNC_(a, 'b', 100) AS a FROM (VALUES (NAMED_STRUCT('a', 1,
'b', 2, 'b', 3)) AS T(a));
+ {"a":1,"b":100,"b":100}
+ > SELECT _FUNC_(a, 'a', _FUNC_(a.a, 'c', 3)) AS a FROM (VALUES
(NAMED_STRUCT('a', NAMED_STRUCT('a', 1, 'b', 2))) AS T(a));
+ {"a":{"a":1,"b":2,"c":3}}
+ """)
+// scalastyle:on line.size.limit
+case class AddFields(children: Seq[Expression]) extends Unevaluable {
+
+ private lazy val ogStructExpr = children.head
+ private lazy val ogStructType =
ogStructExpr.dataType.asInstanceOf[StructType]
+ private lazy val (nameExprs, valExprs) = children.drop(1).grouped(2).map {
+ case Seq(name, value) => (name, value)
+ }.toList.unzip
+ private lazy val names = nameExprs.map(e =>
Option(e.eval()).map(_.toString).orNull)
+ private lazy val addOrReplaceExprs = names.zip(valExprs)
+
+ override def checkInputDataTypes(): TypeCheckResult = {
+ val expectedStructType = StructType(Nil).typeName
+ if (children.size % 2 == 0) {
+ TypeCheckResult.TypeCheckFailure(s"$prettyName expects an odd number of
arguments.")
+ } else if (ogStructExpr.dataType.typeName != expectedStructType) {
+ TypeCheckResult.TypeCheckFailure(
+ s"Only $expectedStructType is allowed to appear at first position,
got: " +
+ s"${ogStructExpr.dataType.typeName}.")
+ } else if (names.contains(null)) {
+ TypeCheckResult.TypeCheckFailure("Field name should not be null.")
+ } else if (nameExprs.exists(e => !(e.foldable && e.dataType ==
StringType))) {
+ TypeCheckResult.TypeCheckFailure(
+ s"Only foldable ${StringType.catalogString} expressions are allowed to
appear at even " +
+ "position.")
+ } else {
+ TypeCheckResult.TypeCheckSuccess
+ }
+ }
+
+ override def dataType: StructType = {
+ val ogStructFields = ogStructType.fields.map { f =>
+ (f.name, f.copy(nullable = ogStructExpr.nullable || f.nullable))
+ }
+ val addOrReplaceStructFields = addOrReplaceExprs.map { case (name, expr) =>
+ (name, StructField(name, expr.dataType, expr.nullable))
+ }
+ val newStructFields = addOrReplace(ogStructFields,
addOrReplaceStructFields).map(_._2)
+ StructType(newStructFields)
+ }
+
+ override def foldable: Boolean = children.forall(_.foldable)
+
+ override def nullable: Boolean = false
+
+ override def prettyName: String = "add_fields"
+
+ def toCreateNamedStruct: CreateNamedStruct = {
+ val ogStructExprs = ogStructType.fieldNames.zipWithIndex.map {
+ case (name, i) => (name, GetStructField(ogStructExpr, i, Some(name)))
+ }
+ val newStructExprs = addOrReplace(ogStructExprs,
addOrReplaceExprs).flatMap {
+ case (name, valExpr) => Seq(Literal(name), valExpr)
+ }
+ CreateNamedStruct(newStructExprs)
+ }
+
+ def addOrReplace[T](
+ existingFields: Seq[(String, T)],
+ addOrReplaceFields: Seq[(String, T)]): Seq[(String, T)] = {
+
+ addOrReplaceFields.foldLeft(existingFields) { case (newFields, field @
(fieldName, _)) =>
+ if (newFields.exists { case (name, _) => name == fieldName }) {
Review comment:
Minor, we might consider to use linked hash map which preserves the
order here, so it's constant time lookup. Also, the code can be simpler since
we can just look up the key, and if it exists, we update the map, if not, we
add it into the map.
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