Replace FunctionFieldReferenceOperator with Calcite DOT operator

coral-hive/src/main/java/com/linkedin/coral/hive/hive2rel/CoralConvertletTable.java

@@ -16,8 +16,6 @@
 import org.apache.calcite.sql2rel.SqlRexConvertlet;
 import org.apache.calcite.sql2rel.StandardConvertletTable;
 
-import com.linkedin.coral.common.functions.FunctionFieldReferenceOperator;
-
 
 /**
  * ConvertletTable for transformations only relevant to Coral's Intermediate Representation, not specific
@@ -26,14 +24,6 @@
  */
 public class CoralConvertletTable extends ReflectiveConvertletTable {
 
-  @SuppressWarnings("unused")
-  public RexNode convertFunctionFieldReferenceOperator(SqlRexContext cx, FunctionFieldReferenceOperator op,
-      SqlCall call) {
-    RexNode funcExpr = cx.convertExpression(call.operand(0));
-    String fieldName = FunctionFieldReferenceOperator.fieldNameStripQuotes(call.operand(1));
-    return cx.getRexBuilder().makeFieldAccess(funcExpr, fieldName, false);
-  }
-
   /**
    * Override {@link StandardConvertletTable#convertCast} to avoid cast optimizations that remove the cast.
    */

coral-hive/src/main/java/com/linkedin/coral/hive/hive2rel/HiveSqlValidator.java

@@ -1,5 +1,5 @@
 /**
- * Copyright 2017-2023 LinkedIn Corporation. All rights reserved.
+ * Copyright 2017-2024 LinkedIn Corporation. All rights reserved.
  * Licensed under the BSD-2 Clause license.
  * See LICENSE in the project root for license information.
  */
@@ -9,7 +9,6 @@
 import org.apache.calcite.config.NullCollation;
 import org.apache.calcite.prepare.CalciteCatalogReader;
 import org.apache.calcite.rel.type.RelDataType;
-import org.apache.calcite.sql.SqlBasicCall;
 import org.apache.calcite.sql.SqlInsert;
 import org.apache.calcite.sql.SqlNode;
 import org.apache.calcite.sql.SqlOperatorTable;
@@ -19,8 +18,6 @@
 import org.apache.calcite.sql.validate.SqlValidatorImpl;
 import org.apache.calcite.sql.validate.SqlValidatorScope;
 
-import com.linkedin.coral.common.functions.FunctionFieldReferenceOperator;
-
 
 public class HiveSqlValidator extends SqlValidatorImpl {
 
@@ -51,15 +48,4 @@ protected void inferUnknownTypes(RelDataType inferredType, SqlValidatorScope sco
     super.inferUnknownTypes(inferredType, scope, node);
   }
 
-  @Override
-  public SqlNode expand(SqlNode expr, SqlValidatorScope scope) {
-    if (expr instanceof SqlBasicCall
-        && ((SqlBasicCall) expr).getOperator().equals(FunctionFieldReferenceOperator.DOT)) {
-      SqlBasicCall dotCall = (SqlBasicCall) expr;
-      if (dotCall.operand(0) instanceof SqlBasicCall) {
-        return expr;
-      }
-    }
-    return super.expand(expr, scope);
-  }
 }

coral-hive/src/main/java/com/linkedin/coral/hive/hive2rel/parsetree/ParseTreeBuilder.java

@@ -48,7 +48,6 @@
 import com.linkedin.coral.com.google.common.collect.Iterables;
 import com.linkedin.coral.common.functions.CoralSqlUnnestOperator;
 import com.linkedin.coral.common.functions.Function;
-import com.linkedin.coral.common.functions.FunctionFieldReferenceOperator;
 import com.linkedin.coral.hive.hive2rel.functions.HiveFunctionResolver;
 import com.linkedin.coral.hive.hive2rel.functions.HiveJsonTupleOperator;
 import com.linkedin.coral.hive.hive2rel.functions.HiveRLikeOperator;
@@ -523,7 +522,7 @@ protected SqlNode visitDotOperator(ASTNode node, ParseContext ctx) {
       Iterable<String> names = Iterables.concat(left.names, right.names);
       return new SqlIdentifier(ImmutableList.copyOf(names), ZERO);
     } else {
-      return FunctionFieldReferenceOperator.DOT.createCall(ZERO, sqlNodes);
+      return SqlStdOperatorTable.DOT.createCall(ZERO, sqlNodes);
     }
   }
 

coral-hive/src/main/java/com/linkedin/coral/transformers/CoralRelToSqlNodeConverter.java

@@ -1,5 +1,5 @@
 /**
- * Copyright 2017-2023 LinkedIn Corporation. All rights reserved.
+ * Copyright 2017-2024 LinkedIn Corporation. All rights reserved.
  * Licensed under the BSD-2 Clause license.
  * See LICENSE in the project root for license information.
  */
@@ -49,7 +49,6 @@
 import com.linkedin.coral.com.google.common.collect.ImmutableList;
 import com.linkedin.coral.com.google.common.collect.ImmutableMap;
 import com.linkedin.coral.common.functions.CoralSqlUnnestOperator;
-import com.linkedin.coral.common.functions.FunctionFieldReferenceOperator;
 
 
 /**
@@ -474,7 +473,7 @@ private SqlNode generateRightChildForSqlJoinWithLateralViews(BiRel e, Result rig
    * Calcite converts it to a {@link SqlIdentifier} with {@link SqlIdentifier#names} as ["f(x)", "y"] where "f(x)" and "y" are String,
    * which is opaque and not aligned with our expectation, since we want to apply transformations on `f(x)` with
    * {@link com.linkedin.coral.common.transformers.SqlCallTransformer}. Therefore, we override this
-   * method to convert `f(x)` to {@link SqlCall} and `.` to {@link com.linkedin.coral.common.functions.FunctionFieldReferenceOperator#DOT}.
+   * method to convert `f(x)` to {@link SqlCall} and `.` to {@link SqlStdOperatorTable#DOT}.
    *
    * With this override, the converted CoralSqlNode matches the previous SqlNode handed over to Calcite for validation and conversion
    * in `HiveSqlToRelConverter#convertQuery`.
@@ -500,7 +499,7 @@ public SqlNode toSql(RexProgram program, RexNode rex) {
             SqlNode functionCall = toSql(program, referencedExpr);
             Collections.reverse(accessNames);
             for (String accessName : accessNames) {
-              functionCall = FunctionFieldReferenceOperator.DOT.createCall(SqlParserPos.ZERO, functionCall,
+              functionCall = SqlStdOperatorTable.DOT.createCall(SqlParserPos.ZERO, functionCall,
                   new SqlIdentifier(accessName, POS));
             }
             return functionCall;

coral-spark/src/test/java/com/linkedin/coral/spark/CoralSparkTest.java

@@ -440,7 +440,7 @@ public void testUnionExtractUDFOnSingleTypeUnions() {
 
     RelNode relNode3 = TestUtils.toRelNode("SELECT extract_union(baz).single.tag_0 from union_table");
     String targetSql4 =
-        "SELECT (coalesce_struct(union_table.baz, 'struct<single:uniontype<array<string>>>').single).tag_0\n"
+        "SELECT coalesce_struct(union_table.baz, 'struct<single:uniontype<array<string>>>').single.tag_0\n"
             + "FROM default.union_table union_table";
     assertEquals(createCoralSpark(relNode3).getSparkSql(), targetSql4);
   }
@@ -876,9 +876,17 @@ public void testSelectStar() {
 
   @Test
   public void testConvertFieldAccessOnFunctionCall() {
+    RelNode relNode = TestUtils.toRelNode("SELECT named_struct('a', 1).a");
+
+    String targetSql = "SELECT named_struct('a', 1).a\n" + "FROM (VALUES  (0)) t (ZERO)";
+    assertEquals(createCoralSpark(relNode).getSparkSql(), targetSql);
+  }
+
+  @Test
+  public void testConvertNestedFieldAccessOnFunctionCall() {
     RelNode relNode = TestUtils.toRelNode("SELECT named_struct('a', named_struct('b', 1)).a.b");
 
-    String targetSql = "SELECT (named_struct('a', named_struct('b', 1)).a).b\n" + "FROM (VALUES  (0)) t (ZERO)";
+    String targetSql = "SELECT named_struct('a', named_struct('b', 1)).a.b\n" + "FROM (VALUES  (0)) t (ZERO)";
     assertEquals(createCoralSpark(relNode).getSparkSql(), targetSql);
   }
 

coral-trino/src/main/java/com/linkedin/coral/trino/rel2trino/RelToTrinoConverter.java

@@ -31,7 +31,6 @@
 import com.linkedin.coral.com.google.common.collect.ImmutableList;
 import com.linkedin.coral.common.HiveMetastoreClient;
 import com.linkedin.coral.common.functions.CoralSqlUnnestOperator;
-import com.linkedin.coral.common.functions.FunctionFieldReferenceOperator;
 import com.linkedin.coral.transformers.CoralRelToSqlNodeConverter;
 
 import static com.google.common.base.Preconditions.*;
@@ -441,7 +440,7 @@ public SqlNode toSql(RexProgram program, RexNode rex) {
             SqlNode functionCall = toSql(program, referencedExpr);
             Collections.reverse(accessNames);
             for (String accessName : accessNames) {
-              functionCall = FunctionFieldReferenceOperator.DOT.createCall(SqlParserPos.ZERO, functionCall,
+              functionCall = SqlStdOperatorTable.DOT.createCall(SqlParserPos.ZERO, functionCall,
                   new SqlIdentifier(accessName, POS));
             }
             return functionCall;