Github user viirya commented on a diff in the pull request:
https://github.com/apache/spark/pull/14277#discussion_r71638204
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
---
@@ -204,6 +204,29 @@ case class Elt(children: Seq[Expression])
}
}
}
+
+ override protected def doGenCode(ctx: CodegenContext, ev: ExprCode):
ExprCode = {
+ val index = children.head.map(_.genCode(ctx))(0)
+ val strings = children.tail.map(_.genCode(ctx))
+ val stringValues = strings.map { eval =>
+ s"${eval.isNull} ? null : ${eval.value}"
+ }.mkString(", ")
+ val indexVal = ctx.freshName("index")
+ val stringArray = ctx.freshName("strings");
+
+ ev.copy(index.code + "\n" + strings.map(_.code).mkString("\n") + s"""
+ int $indexVal = ${index.value} - 1;
+ UTF8String[] $stringArray = {$stringValues};
--- End diff --
Because the index is only evaluated runtime, I think we can' just evaluate
the string we need? Or we can wrap these string expressions in an if/else if or
switch block, then we can only evaluate the string expression specified by the
index. What do you think?
---
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.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
