[GitHub] spark pull request #13976: [SPARK-16288][SQL] Implement inline table generat...

[dongjoon-hyun <gi...@git.apache.org>]

Github user dongjoon-hyun commented on a diff in the pull request:

    https://github.com/apache/spark/pull/13976#discussion_r69230152
  
    --- Diff: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/generators.scala ---
    @@ -195,3 +195,43 @@ case class Explode(child: Expression) extends ExplodeBase(child, position = fals
       extended = "> SELECT _FUNC_(array(10,20));\n  0\t10\n  1\t20")
     // scalastyle:on line.size.limit
     case class PosExplode(child: Expression) extends ExplodeBase(child, position = true)
    +
    +/**
    + * Explodes an array of structs into a table.
    + */
    +@ExpressionDescription(
    +  usage = "_FUNC_(a) - Explodes an array of structs into a table.",
    +  extended = "> SELECT _FUNC_(array(struct(1, 'a'), struct(2, 'b')));\n [1,a]\n[2,b]")
    +case class Inline(child: Expression) extends UnaryExpression with Generator with CodegenFallback {
    +
    +  override def children: Seq[Expression] = child :: Nil
    +
    +  override def checkInputDataTypes(): TypeCheckResult = child.dataType match {
    +    case ArrayType(et, _) if et.isInstanceOf[StructType] =>
    +      TypeCheckResult.TypeCheckSuccess
    +    case _ =>
    +      TypeCheckResult.TypeCheckFailure(
    +        s"input to function inline should be array of struct type, not ${child.dataType}")
    +  }
    +
    +  override def elementSchema: StructType = child.dataType match {
    +    case ArrayType(et : StructType, _) =>
    +      var schema = new StructType()
    +      for (f <- et.fields.zipWithIndex) {
    +        schema = schema.add(s"col${f._2 + 1}", f._1.dataType, nullable = f._1.nullable)
    +      }
    +      schema
    +  }
    +
    +  override def eval(input: InternalRow): TraversableOnce[InternalRow] = child.dataType match {
    +    case ArrayType(NullType, _) => Nil
    --- End diff --
    
    Actually, I added this to pass the `Seq.empty` testcase.
    https://github.com/apache/spark/pull/13976/files#diff-6715134a4e95980149a7600ecb71674cR80
    
    But, now, I think I added this without deep thought.



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