[GitHub] [spark] HyukjinKwon commented on a diff in pull request #40528: [SPARK-42584][CONNECT] Improve output of Column.explain

["HyukjinKwon (via GitHub)" <gi...@apache.org>]

HyukjinKwon commented on code in PR #40528:
URL: https://github.com/apache/spark/pull/40528#discussion_r1250433691


##########
connector/connect/client/jvm/src/main/scala/org/apache/spark/sql/expressions/ProtoExpressionSQLBuilder.scala:
##########
@@ -0,0 +1,213 @@
+/*
+ * 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.expressions
+
+import scala.collection.JavaConverters._
+
+import org.apache.spark.connect.proto
+import org.apache.spark.sql.connect.common.{DataTypeProtoConverter, InvalidPlanInput, LiteralValueProtoConverter}
+
+/**
+ * The builder to generate SQL from proto expressions.
+ */
+class ProtoExpressionSQLBuilder(expr: proto.Expression, extended: Boolean) {
+
+  def build(): String = generate(expr)
+
+  private def generate(expr: proto.Expression): String = {
+    expr.getExprTypeCase match {
+      case proto.Expression.ExprTypeCase.LITERAL => visitLiteral(expr.getLiteral)
+      case proto.Expression.ExprTypeCase.UNRESOLVED_ATTRIBUTE =>
+        visitUnresolvedAttribute(expr.getUnresolvedAttribute)
+      case proto.Expression.ExprTypeCase.UNRESOLVED_FUNCTION =>
+        visitUnresolvedFunction(expr.getUnresolvedFunction)
+      case proto.Expression.ExprTypeCase.UNRESOLVED_EXTRACT_VALUE =>
+        visitUnresolvedExtractValue(expr.getUnresolvedExtractValue)
+      case proto.Expression.ExprTypeCase.UPDATE_FIELDS =>
+        visitUpdateFields(expr.getUpdateFields)
+      case proto.Expression.ExprTypeCase.ALIAS => visitAlias(expr.getAlias)
+      case proto.Expression.ExprTypeCase.CAST =>
+        val cast = expr.getCast
+        cast.getCastToTypeCase match {
+          case proto.Expression.Cast.CastToTypeCase.TYPE =>
+            visitCast(expr.getCast)
+          case _ => visitUnexpectedExpr(expr)
+        }
+      case proto.Expression.ExprTypeCase.SORT_ORDER => visitSortOrder(expr.getSortOrder)
+      case _ =>
+        throw InvalidPlanInput(
+          s"Expression with ID: ${expr.getExprTypeCase.getNumber} is not supported")
+    }
+  }
+
+  private def visitLiteral(literal: proto.Expression.Literal): String = {
+    val value = LiteralValueProtoConverter.toCatalystValue(literal)
+    literal.getLiteralTypeCase match {
+      case proto.Expression.Literal.LiteralTypeCase.STRING =>
+        s"'$value'"
+      case _ =>
+        s"$value"
+    }
+  }
+
+  private def visitUnresolvedAttribute(attr: proto.Expression.UnresolvedAttribute): String =
+    attr.getUnparsedIdentifier
+
+  private def visitUnresolvedFunction(fun: proto.Expression.UnresolvedFunction): String = {
+    val functionName = fun.getFunctionName
+    functionName match {
+      case "=" | "<=>" | "<" | "<=" | ">" | ">=" =>
+        visitBinaryComparison(
+          functionName,
+          generate(fun.getArguments(0)),
+          generate(fun.getArguments(1)))
+      case "+" | "-" | "*" | "/" | "%" | "&" | "|" | "^" =>
+        visitBinaryArithmetic(
+          functionName,
+          generate(fun.getArguments(0)),
+          generate(fun.getArguments(1)))
+      case "and" | "or" =>
+        visitOr(functionName, generate(fun.getArguments(0)), generate(fun.getArguments(1)))
+      case "negative" =>
+        visitUnaryArithmetic("-", generate(fun.getArguments(0)))
+      case "!" =>
+        visitUnaryArithmetic("NOT", generate(fun.getArguments(0)))
+      case "when" =>
+        visitCaseWhen(fun.getArgumentsList.asScala.toSeq.map(generate(_)))
+      case "isNull" =>
+        visitIsNull(generate(fun.getArguments(0)))
+      case "isNotNull" =>
+        visitIsNotNull(generate(fun.getArguments(0)))
+      case "in" =>
+        visitJoin(fun.getArgumentsList.asScala.toSeq.map(generate(_)))
+      case "like" =>
+        visitLike(generate(fun.getArguments(0)), generate(fun.getArguments(1)))
+      case "isNaN" =>
+        visitCommonFunction("isnan", fun.getArgumentsList.asScala.toSeq.map(generate(_)))
+      case "rlike" =>
+        visitCommonFunction("RLIKE", fun.getArgumentsList.asScala.toSeq.map(generate(_)))
+      case "substr" =>
+        visitCommonFunction("substring", fun.getArgumentsList.asScala.toSeq.map(generate(_)))
+      case "ilike" | "contains" | "startswith" | "endswith" =>
+        visitCommonFunction(functionName, fun.getArgumentsList.asScala.toSeq.map(generate(_)))
+      // TODO: Support more functions
+    }
+  }
+
+  private def visitBinaryComparison(name: String, l: String, r: String): String =
+    s"($l $name $r)"

Review Comment:
   I think this is too much for cosmetic changes, and even with this it can't address all the cases, right? e.g., unresolved column such as `a AS b`. In non Spark Connect, it will be shown `b` IIRC.



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org
For additional commands, e-mail: reviews-help@spark.apache.org