[GitHub] [spark] gengliangwang commented on a change in pull request #32292: [WIP][SPARK-35162][SQL] New SQL functions: TRY_ADD/TRY_SUBTRACT/TRY_MULTIPLY/TRY_DIVIDE/TRY_DIV

[GitBox <gi...@apache.org>]

gengliangwang commented on a change in pull request #32292:
URL: https://github.com/apache/spark/pull/32292#discussion_r618228127



##########
File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Try.scala
##########
@@ -0,0 +1,58 @@
+/*
+ * 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.catalyst.expressions
+
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.expressions.codegen.{CodegenContext, CodeGenerator, ExprCode}
+import org.apache.spark.sql.catalyst.expressions.codegen.Block._
+import org.apache.spark.sql.types.DataType
+
+case class Try(child: Expression) extends UnaryExpression {
+  override protected def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+    val childGen = child.genCode(ctx)
+    ev.copy(code = code"""
+      boolean ${ev.isNull} = true;
+      ${CodeGenerator.javaType(dataType)} ${ev.value} = ${CodeGenerator.defaultValue(dataType)};
+      try {
+        ${childGen.code}
+        ${ev.isNull} = ${childGen.isNull};
+        ${ev.value} = ${childGen.value};
+      } catch (Exception e) {
+      }"""
+    )
+  }
+
+  override def eval(input: InternalRow): Any =
+    try {
+      child.eval(input)
+    } catch {
+      case _: Exception =>
+        null
+    }
+
+  override def dataType: DataType = child.dataType
+
+  override def nullable: Boolean = true
+
+  override protected def withNewChildInternal(newChild: Expression): Expression =
+    copy(child = newChild)
+
+  override def sql: String = s"try${child.sql}"

Review comment:
       I will fix the `sql`/`toString` method. This is still WIP.




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