Github user hvanhovell commented on a diff in the pull request:
https://github.com/apache/spark/pull/13706#discussion_r118846647
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/command/macros.scala ---
@@ -0,0 +1,99 @@
+/*
+ * 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.spark.sql.execution.command
+
+import org.apache.spark.sql.{AnalysisException, Row, SparkSession}
+import org.apache.spark.sql.catalyst.analysis._
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.types.StructField
+
+/**
+ * This class provides arguments and body expression of the macro function.
+ */
+case class MacroFunctionWrapper(columns: Seq[StructField], macroFunction:
Expression)
+
+/**
+ * The DDL command that creates a macro.
+ * To create a temporary macro, the syntax of using this command in SQL is:
+ * {{{
+ * CREATE TEMPORARY MACRO macro_name([col_name col_type, ...])
expression;
+ * }}}
+ */
+case class CreateMacroCommand(
+ macroName: String,
+ funcWrapper: MacroFunctionWrapper)
+ extends RunnableCommand {
+
+ override def run(sparkSession: SparkSession): Seq[Row] = {
+ val catalog = sparkSession.sessionState.catalog
+ val columns = funcWrapper.columns.map { col =>
+ AttributeReference(col.name, col.dataType, col.nullable,
col.metadata)() }
+ val colToIndex: Map[String, Int] =
columns.map(_.name).zipWithIndex.toMap
+ if (colToIndex.size != columns.size) {
+ throw new AnalysisException(s"Cannot support duplicate colNames " +
+ s"for CREATE TEMPORARY MACRO $macroName, actual columns:
${columns.mkString(",")}")
+ }
+ val macroFunction = funcWrapper.macroFunction.transform {
+ case u: UnresolvedAttribute =>
+ val index = colToIndex.get(u.name).getOrElse(
+ throw new AnalysisException(s"Cannot find colName: ${u} " +
+ s"for CREATE TEMPORARY MACRO $macroName, actual columns:
${columns.mkString(",")}"))
+ BoundReference(index, columns(index).dataType,
columns(index).nullable)
+ case u: UnresolvedFunction =>
+ sparkSession.sessionState.catalog.lookupFunction(u.name,
u.children)
+ case s: SubqueryExpression =>
+ throw new AnalysisException(s"Cannot support Subquery: ${s} " +
+ s"for CREATE TEMPORARY MACRO $macroName")
+ case u: UnresolvedGenerator =>
+ throw new AnalysisException(s"Cannot support Generator: ${u} " +
+ s"for CREATE TEMPORARY MACRO $macroName")
+ }
+
+ val macroInfo = columns.mkString(",") + " -> " +
funcWrapper.macroFunction.toString
+ val info = new ExpressionInfo(macroInfo, macroName, true)
+ val builder = (children: Seq[Expression]) => {
+ if (children.size != columns.size) {
+ throw new AnalysisException(s"Actual number of columns:
${children.size} != " +
+ s"expected number of columns: ${columns.size} for Macro
$macroName")
+ }
+ macroFunction.transform {
+ // Skip to validate the input type because check it at runtime.
--- End diff --
On a related note, we are currently not sure if the macro produces a valid
expression. Maybe we should run analysis on the macro expression to make sure
it does not fail every query later on, e.g.:
```scala
val resolvedMacroFunction = try {
val plan = Project(Alias(macroFunction, "m")() :: Nil, OneRowRelation)
val analyzed @ Project(Seq(named), OneRowRelation) =
sparkSession.sessionState.analyzer.execute(plan)
sparkSession.sessionState.analyzer.checkAnalysis(analyzed)
named.children.head
} catch {
case a: AnalysisException =>
...
}
```
Note that we cannot use generators if we use this approach...
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