YQL-19123 More SQL features for Variant type

More SQL features for Variant type
commit_hash:51c15343e2d24190ec59085888dfa3fd008cafcc

9 files changed, 477 insertions, 12 deletions

diff --git a/yql/essentials/core/type_ann/type_ann_core.cpp b/yql/essentials/core/type_ann/type_ann_core.cpp
index 2474f046ae..8dd928d4aa 100644
--- a/yql/essentials/core/type_ann/type_ann_core.cpp
+++ b/yql/essentials/core/type_ann/type_ann_core.cpp
@@ -946,6 +946,30 @@ namespace NTypeAnnImpl {
         return result;
     }
 
+    TMaybe<ui32> FindOrReportMissingMember(TStringBuf memberName, const TTupleExprType& tupleType, TString& errStr) {
+        ui32 index = 0;
+        if (!TryFromString(memberName, index)) {
+            errStr = TStringBuilder() << "Failed to convert to integer: " << memberName;
+            return Nothing();
+        }
+        if (index >= tupleType.GetSize()) {
+            errStr = TStringBuilder()
+                << "Index out of range. Index: "
+                << index << ", size: " << tupleType.GetSize();
+            return Nothing();
+        }
+        return index;
+    }
+
+    TMaybe<ui32> FindOrReportMissingMember(TStringBuf memberName, TPositionHandle pos, const TTupleExprType& tupleType, TExprContext& ctx) {
+        TString errStr;
+        auto result = FindOrReportMissingMember(memberName, tupleType, errStr);
+        if (!result) {
+            ctx.AddError(TIssue(ctx.GetPosition(pos), errStr));
+        }
+        return result;
+    }
+
     IGraphTransformer::TStatus MemberWrapper(const TExprNode::TPtr& input, TExprNode::TPtr& output, TContext& ctx) {
         if (!EnsureArgsCount(*input, 2, ctx.Expr)) {
             return IGraphTransformer::TStatus::Error;
@@ -8534,6 +8558,50 @@ template <NKikimr::NUdf::EDataSlot DataSlot>
         return IGraphTransformer::TStatus::Ok;
     }
 
+    IGraphTransformer::TStatus SqlVariantItemWrapper(const TExprNode::TPtr& input, TExprNode::TPtr& output, TContext& ctx) {
+        if (!EnsureArgsCount(*input, 1, ctx.Expr)) {
+            return IGraphTransformer::TStatus::Error;
+        }
+
+        if (IsNull(input->Head())) {
+            output = input->HeadPtr();
+            return IGraphTransformer::TStatus::Repeat;
+        }
+
+        if (input->Head().GetTypeAnn() && input->Head().GetTypeAnn()->GetKind() == ETypeAnnotationKind::Optional) {
+            auto optType = input->Head().GetTypeAnn()->Cast<TOptionalExprType>();
+            if (!EnsureVariantType(input->Head().Pos(), *optType->GetItemType(), ctx.Expr)) {
+                return IGraphTransformer::TStatus::Error;
+            }
+            auto varType = optType->GetItemType()->Cast<TVariantExprType>();
+            auto isOptionalItem = false;
+            if (varType->GetUnderlyingType()->GetKind() == ETypeAnnotationKind::Tuple) {
+                auto tupType = varType->GetUnderlyingType()->Cast<TTupleExprType>();
+                if (tupType->GetSize() > 0 && tupType->GetItems()[0]->GetKind() == ETypeAnnotationKind::Optional) {
+                    isOptionalItem = true;
+                }
+            } else {
+                auto strType = varType->GetUnderlyingType()->Cast<TStructExprType>();
+                if (strType->GetSize() > 0 && strType->GetItems()[0]->GetItemType()->GetKind() == ETypeAnnotationKind::Optional) {
+                    isOptionalItem = true;
+                }
+            }
+            output = ctx.Expr.Builder(input->Pos())
+                .Callable(isOptionalItem ? "FlatMap" : "Map")
+                    .Add(0, input->HeadPtr())
+                    .Lambda(1)
+                        .Param("var")
+                        .Callable("VariantItem")
+                            .Arg(0, "var")
+                        .Seal()
+                    .Seal()
+                .Seal().Build();
+        } else {
+            output = ctx.Expr.RenameNode(*input, "VariantItem");
+        }
+        return IGraphTransformer::TStatus::Repeat;
+    }
+
     IGraphTransformer::TStatus VariantItemWrapper(const TExprNode::TPtr& input, TExprNode::TPtr& output, TContext& ctx) {
         Y_UNUSED(output);
         if (!EnsureArgsCount(*input, 1, ctx.Expr)) {
@@ -8591,6 +8659,112 @@ template <NKikimr::NUdf::EDataSlot DataSlot>
         return IGraphTransformer::TStatus::Ok;
     }
 
+    IGraphTransformer::TStatus SqlVisitWrapper(const TExprNode::TPtr& input, TExprNode::TPtr& output, TContext& ctx) {
+        if (!EnsureMinArgsCount(*input, 2, ctx.Expr)) {
+            return IGraphTransformer::TStatus::Error;
+        }
+
+        if (IsNull(input->Head())) {
+            output = input->HeadPtr();
+            return IGraphTransformer::TStatus::Repeat;
+        }
+
+        if (input->Head().GetTypeAnn() && input->Head().GetTypeAnn()->GetKind() == ETypeAnnotationKind::Optional) {
+            auto appendOtherArgs = [&] (auto &builder) -> auto {
+                for (size_t pos = 1; pos < input->ChildrenSize(); pos++) {
+                    builder.Add(pos, input->ChildPtr(pos));
+                }
+                return builder;
+            };
+
+            auto optType = input->Head().GetTypeAnn()->Cast<TOptionalExprType>();
+            if (!EnsureVariantType(input->Pos(), *optType->GetItemType(), ctx.Expr)) {
+                return IGraphTransformer::TStatus::Error;
+            }
+            auto varType = optType->GetItemType()->Cast<TVariantExprType>();
+            const TTupleExprType* tupType = nullptr;
+            const TStructExprType* strType = nullptr;
+            if (varType->GetUnderlyingType()->GetKind() == ETypeAnnotationKind::Tuple) {
+                tupType = varType->GetUnderlyingType()->Cast<TTupleExprType>();
+            } else {
+                strType = varType->GetUnderlyingType()->Cast<TStructExprType>();
+            }
+
+            bool isOptionalResult = false;
+            bool repeat = false;
+            for (size_t idx = 1; idx < input->ChildrenSize(); idx++) {
+                auto child = input->ChildPtr(idx);
+                if (child->IsAtom()) {
+                    const TTypeAnnotationNode* itemType;
+                    if (tupType) {
+                        auto pos = FindOrReportMissingMember(child->Content(), child->Pos(), *tupType, ctx.Expr);
+                        if (!pos) {
+                            return IGraphTransformer::TStatus::Error;
+                        }
+                        itemType = tupType->GetItems()[*pos];
+                    } else {
+                        auto pos = FindOrReportMissingMember(child->Content(), child->Pos(), *strType, ctx.Expr);
+                        if (!pos) {
+                            return IGraphTransformer::TStatus::Error;
+                        }
+                        itemType = strType->GetItems()[*pos]->GetItemType();
+                    }
+
+                    idx++;
+                    if (idx == input->ChildrenSize()) {
+                        ctx.Expr.AddError(TIssue(ctx.Expr.GetPosition(child->Pos()), "Expected lambda after this argument"));
+                        return IGraphTransformer::TStatus::Error;
+                    }
+
+                    auto status = ConvertToLambda(input->ChildRef(idx), ctx.Expr, 1);
+                    if (status.Level != IGraphTransformer::TStatus::Ok) {
+                        return status;
+                    }
+
+                    auto& lambda = input->ChildRef(idx);
+                    if (!UpdateLambdaAllArgumentsTypes(lambda, {itemType}, ctx.Expr)) {
+                        return IGraphTransformer::TStatus::Error;
+                    }
+
+                    if (!lambda->GetTypeAnn()) {
+                        repeat = true;
+                        continue;
+                    }
+
+                    if (lambda->GetTypeAnn()->GetKind() == ETypeAnnotationKind::Optional) {
+                        isOptionalResult = true;
+                    }
+                } else {
+                    if (!EnsureComputable(*child, ctx.Expr)) {
+                        return IGraphTransformer::TStatus::Error;
+                    }
+                    if (child->GetTypeAnn()->GetKind() == ETypeAnnotationKind::Optional) {
+                        isOptionalResult = true;
+                    }
+                }
+            }
+
+            if (repeat) {
+                return IGraphTransformer::TStatus::Repeat;
+            }
+
+            output = appendOtherArgs(ctx.Expr.Builder(input->Pos())
+                .Callable(isOptionalResult ? "FlatMap" : "Map")
+                    .Add(0, input->HeadPtr())
+                    .Lambda(1)
+                        .Param("var")
+                        .Callable("Visit")
+                            .Arg(0, "var"))
+                        .Seal()
+                    .Seal()
+                .Seal().Build();
+        } else {
+            output = ctx.Expr.RenameNode(*input, "Visit");
+        }
+
+        return IGraphTransformer::TStatus::Repeat;
+    }
+
     IGraphTransformer::TStatus VisitWrapper(const TExprNode::TPtr& input, TExprNode::TPtr& output, TContext& ctx) {
         Y_UNUSED(output);
         if (!EnsureMinArgsCount(*input, 2, ctx.Expr)) {
@@ -8625,21 +8799,13 @@ template <NKikimr::NUdf::EDataSlot DataSlot>
                 const TTypeAnnotationNode* itemType;
                 ui32 itemIndex;
                 if (tupleType) {
-                    ui32 index = 0;
-                    if (!TryFromString(child->Content(), index)) {
-                        ctx.Expr.AddError(TIssue(ctx.Expr.GetPosition(child->Pos()), TStringBuilder() << "Failed to convert to integer: " << child->Content()));
-                        return IGraphTransformer::TStatus::Error;
-                    }
-
-                    if (index >= tupleType->GetSize()) {
-                        ctx.Expr.AddError(TIssue(ctx.Expr.GetPosition(child->Pos()), TStringBuilder()
-                            << "Index out of range. Index: "
-                            << index << ", size: " << tupleType->GetSize()));
+                    auto pos = FindOrReportMissingMember(child->Content(), child->Pos(), *tupleType, ctx.Expr);
+                    if (!pos) {
                         return IGraphTransformer::TStatus::Error;
                     }
 
-                    itemType = tupleType->GetItems()[index];
-                    itemIndex = index;
+                    itemType = tupleType->GetItems()[*pos];
+                    itemIndex = *pos;
                 } else {
                     auto pos = FindOrReportMissingMember(child->Content(), child->Pos(), *structType, ctx.Expr);
                     if (!pos) {
@@ -8763,6 +8929,10 @@ template <NKikimr::NUdf::EDataSlot DataSlot>
 
             variantType = itemType->Cast<TVariantExprType>();
         }
+        else if (IsNull(input->Head())) {
+            output = input->HeadPtr();
+            return IGraphTransformer::TStatus::Repeat;
+        }
         else {
             if (!EnsureVariantType(input->Head(), ctx.Expr)) {
                 return IGraphTransformer::TStatus::Error;
@@ -12421,7 +12591,9 @@ template <NKikimr::NUdf::EDataSlot DataSlot>
         Functions["FlattenMembersType"] = &TypeArgWrapper<ETypeArgument::FlattenMembers>;
         Functions["VariantUnderlyingType"] = &TypeArgWrapper<ETypeArgument::VariantUnderlying>;
         Functions["Guess"] = &GuessWrapper;
+        Functions["SqlVariantItem"] = &SqlVariantItemWrapper;
         Functions["VariantItem"] = &VariantItemWrapper;
+        Functions["SqlVisit"] = &SqlVisitWrapper;
         Functions["Visit"] = &VisitWrapper;
         Functions["Way"] = &WayWrapper;
         Functions["SqlAccess"] = &SqlAccessWrapper;
diff --git a/yql/essentials/sql/v1/builtin.cpp b/yql/essentials/sql/v1/builtin.cpp
index 5d33b2061f..a4bec63066 100644
--- a/yql/essentials/sql/v1/builtin.cpp
+++ b/yql/essentials/sql/v1/builtin.cpp
@@ -3010,6 +3010,7 @@ struct TBuiltinFuncData {
             {"callableresulttype", BuildNamedArgcBuiltinFactoryCallback<TCallNodeImpl>("CallableResultType", 1, 1) },
             {"callableargumenttype", BuildSimpleBuiltinFactoryCallback<TYqlCallableArgumentType>() },
             {"variantunderlyingtype", BuildNamedArgcBuiltinFactoryCallback<TCallNodeImpl>("VariantUnderlyingType", 1, 1) },
+            {"variantitem", BuildNamedArgcBuiltinFactoryCallback<TCallNodeImpl>("SqlVariantItem", 1, 1) },
             {"fromysonsimpletype", BuildNamedArgcBuiltinFactoryCallback<TCallNodeImpl>("FromYsonSimpleType", 2, 2) },
             {"currentutcdate", BuildNamedDepsArgcBuiltinFactoryCallback<TCallNodeDepArgs>(0, "CurrentUtcDate", 0, -1) },
             {"currentutcdatetime", BuildNamedDepsArgcBuiltinFactoryCallback<TCallNodeDepArgs>(0, "CurrentUtcDatetime", 0, -1) },
@@ -3705,6 +3706,54 @@ TNodePtr BuildBuiltinFunc(TContext& ctx, TPosition pos, TString name, const TVec
                 BuildTuple(pos, {BuildQuotedAtom(pos, ""), args[1]}),
             };
             return new TCallNodeImpl(pos, "FlattenMembers", 2, 2, flattenMembersArgs);
+        } else if (normalizedName == "visit" || normalizedName == "visitordefault") {
+            bool withDefault = normalizedName == "visitordefault";
+            TNodePtr variant;
+            TVector<TNodePtr> labels, handlers;
+            TMaybe<TNodePtr> dflt;
+            if (mustUseNamed && *mustUseNamed) {
+                *mustUseNamed = false;
+                auto &positional = *args[0]->GetTupleNode();
+                if (positional.GetTupleSize() != (withDefault ? 2 : 1)) {
+                    return new TInvalidBuiltin(pos, TStringBuilder() << name
+                        << " requires exactly " << (withDefault ? 2 : 1) << " positional arguments when named args are used");
+                }
+                auto &named = *args[1]->GetStructNode();
+                variant = positional.GetTupleElement(0);
+                auto &namedExprs = named.GetExprs();
+                labels.reserve(namedExprs.size());
+                handlers.reserve(namedExprs.size());
+                for (size_t idx = 0; idx < namedExprs.size(); idx++) {
+                    labels.push_back(BuildQuotedAtom(pos, namedExprs[idx]->GetLabel()));
+                    handlers.push_back(namedExprs[idx]);
+                }
+                if (withDefault) {
+                    dflt = positional.GetTupleElement(positional.GetTupleSize() - 1);
+                }
+            } else {
+                variant = args[0];
+                size_t defaultSuffix = withDefault ? 1 : 0;
+                labels.reserve(args.size() - 1 - defaultSuffix);
+                handlers.reserve(args.size() - 1 - defaultSuffix);
+                for (size_t idx = 0; idx + 1 < args.size() - defaultSuffix; idx++) {
+                    labels.push_back(BuildQuotedAtom(pos, ToString(idx)));
+                    handlers.push_back(args[idx + 1]);
+                }
+                if (withDefault) {
+                    dflt = args.back();
+                }
+            }
+            TVector<TNodePtr> resultArgs;
+            resultArgs.reserve(1 + labels.size() + handlers.size());
+            resultArgs.emplace_back(std::move(variant));
+            for (size_t idx = 0; idx < labels.size(); idx++) {
+                resultArgs.emplace_back(std::move(labels[idx]));
+                resultArgs.emplace_back(std::move(handlers[idx]));
+            }
+            if (dflt.Defined()) {
+                resultArgs.emplace_back(std::move(dflt->Get()));
+            }
+            return new TCallNodeImpl(pos, "SqlVisit", 1, -1, resultArgs);
         } else if (normalizedName == "sqlexternalfunction") {
             return new TCallNodeImpl(pos, "SqlExternalFunction", args);
         } else {
diff --git a/yql/essentials/tests/sql/sql2yql/canondata/result.json b/yql/essentials/tests/sql/sql2yql/canondata/result.json
index 553fd35c78..ee6df683bf 100644
--- a/yql/essentials/tests/sql/sql2yql/canondata/result.json
+++ b/yql/essentials/tests/sql/sql2yql/canondata/result.json
@@ -6908,6 +6908,13 @@
             "uri": "https://{canondata_backend}/1937429/434276f26b2857be3c5ad3fdbbf877d2bf775ac5/resource.tar.gz#test_sql2yql.test_expr-uuid_order_/sql.yql"
         }
     ],
+    "test_sql2yql.test[expr-variant_builtins_opt]": [
+        {
+            "checksum": "00f7f7ba82bd2474f7b1bfd7771323f9",
+            "size": 3847,
+            "uri": "https://{canondata_backend}/1936842/4ad1682e9f564ef555f5e0180b972a1adad2fc43/resource.tar.gz#test_sql2yql.test_expr-variant_builtins_opt_/sql.yql"
+        }
+    ],
     "test_sql2yql.test[expr-variant_list_sort]": [
         {
             "checksum": "abd93bfb65a1cb17235be843d4cbd2c3",
@@ -6915,6 +6922,13 @@
             "uri": "https://{canondata_backend}/1936273/4a1b39013e1bae40e722cff8ccef8829784964e2/resource.tar.gz#test_sql2yql.test_expr-variant_list_sort_/sql.yql"
         }
     ],
+    "test_sql2yql.test[expr-variant_struct_builtins]": [
+        {
+            "checksum": "cb90540556b74bdbb9a95959c62a3cbf",
+            "size": 5780,
+            "uri": "https://{canondata_backend}/1936842/4ad1682e9f564ef555f5e0180b972a1adad2fc43/resource.tar.gz#test_sql2yql.test_expr-variant_struct_builtins_/sql.yql"
+        }
+    ],
     "test_sql2yql.test[expr-variant_struct_comp]": [
         {
             "checksum": "3f85119441280a8729ef912910ac7745",
@@ -6922,6 +6936,13 @@
             "uri": "https://{canondata_backend}/1936273/4a1b39013e1bae40e722cff8ccef8829784964e2/resource.tar.gz#test_sql2yql.test_expr-variant_struct_comp_/sql.yql"
         }
     ],
+    "test_sql2yql.test[expr-variant_tuple_builtins]": [
+        {
+            "checksum": "41d01afdf58dcca513a44186a279efcb",
+            "size": 5682,
+            "uri": "https://{canondata_backend}/1936842/4ad1682e9f564ef555f5e0180b972a1adad2fc43/resource.tar.gz#test_sql2yql.test_expr-variant_tuple_builtins_/sql.yql"
+        }
+    ],
     "test_sql2yql.test[expr-variant_tuple_comp]": [
         {
             "checksum": "62f3d0d5c99c037db94a4f8f3c3c9d1d",
@@ -24821,16 +24842,31 @@
             "uri": "file://test_sql_format.test_expr-uuid_order_/formatted.sql"
         }
     ],
+    "test_sql_format.test[expr-variant_builtins_opt]": [
+        {
+            "uri": "file://test_sql_format.test_expr-variant_builtins_opt_/formatted.sql"
+        }
+    ],
     "test_sql_format.test[expr-variant_list_sort]": [
         {
             "uri": "file://test_sql_format.test_expr-variant_list_sort_/formatted.sql"
         }
     ],
+    "test_sql_format.test[expr-variant_struct_builtins]": [
+        {
+            "uri": "file://test_sql_format.test_expr-variant_struct_builtins_/formatted.sql"
+        }
+    ],
     "test_sql_format.test[expr-variant_struct_comp]": [
         {
             "uri": "file://test_sql_format.test_expr-variant_struct_comp_/formatted.sql"
         }
     ],
+    "test_sql_format.test[expr-variant_tuple_builtins]": [
+        {
+            "uri": "file://test_sql_format.test_expr-variant_tuple_builtins_/formatted.sql"
+        }
+    ],
     "test_sql_format.test[expr-variant_tuple_comp]": [
         {
             "uri": "file://test_sql_format.test_expr-variant_tuple_comp_/formatted.sql"
diff --git a/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_builtins_opt_/formatted.sql b/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_builtins_opt_/formatted.sql
new file mode 100644
index 0000000000..3023dcf5c2
--- /dev/null
+++ b/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_builtins_opt_/formatted.sql
@@ -0,0 +1,30 @@
+$vartype = Variant<a: Optional<String>, b: Optional<String>>;
+
+$handle_a = ($x) -> {
+    RETURN CAST(($x || "1") AS Uint32);
+};
+
+$handle_b = ($x) -> {
+    RETURN CAST(($x || "2") AS Uint32);
+};
+
+$var_a = VARIANT ("5", "a", $vartype);
+$var_b = VARIANT ("6", "b", $vartype);
+
+SELECT
+    Visit(Just($var_a), $handle_a AS a, $handle_b AS b),
+    Visit(Just($var_b), $handle_a AS a, $handle_b AS b),
+    VisitOrDefault(Just($var_b), Just(777u), $handle_a AS a),
+    VariantItem(Just($var_b))
+;
+
+$vartype_t = Variant<Optional<String>, Optional<String>>;
+$var_1 = VARIANT ("7", "0", $vartype_t);
+$var_2 = VARIANT ("8", "1", $vartype_t);
+
+SELECT
+    Visit(Just($var_1), $handle_a, $handle_b),
+    Visit(Just($var_2), $handle_a, $handle_b),
+    VisitOrDefault(Just($var_2), $handle_a, Just(777u)),
+    VariantItem(Just($var_b))
+;
diff --git a/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_struct_builtins_/formatted.sql b/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_struct_builtins_/formatted.sql
new file mode 100644
index 0000000000..1192a90d9b
--- /dev/null
+++ b/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_struct_builtins_/formatted.sql
@@ -0,0 +1,46 @@
+$vartype = Variant<num: Int32, flag: Bool, str: String>;
+
+$handle_num = ($x) -> {
+    RETURN 2 * $x;
+};
+
+$handle_flag = ($x) -> {
+    RETURN If($x, 200, 10);
+};
+
+$handle_str = ($x) -> {
+    RETURN Unwrap(CAST(LENGTH($x) AS Int32));
+};
+
+$visitor = ($var) -> {
+    RETURN Visit($var, $handle_num AS num, $handle_flag AS flag, $handle_str AS str);
+};
+
+SELECT
+    $visitor(VARIANT (5, "num", $vartype)),
+    $visitor(Just(VARIANT (TRUE, "flag", $vartype))),
+    $visitor(Just(VARIANT ("somestr", "str", $vartype))),
+    $visitor(Nothing(OptionalType($vartype))),
+    $visitor(NULL)
+;
+
+$visitor_def = ($var) -> {
+    RETURN VisitOrDefault($var, 999, $handle_num AS num, $handle_flag AS flag);
+};
+
+SELECT
+    $visitor_def(VARIANT (5, "num", $vartype)),
+    $visitor_def(Just(VARIANT (TRUE, "flag", $vartype))),
+    $visitor_def(Just(VARIANT ("somestr", "str", $vartype))),
+    $visitor_def(Nothing(OptionalType($vartype))),
+    $visitor_def(NULL)
+;
+
+$vartype1 = Variant<num1: Int32, num2: Int32, num3: Int32>;
+
+SELECT
+    VariantItem(VARIANT (7, "num2", $vartype1)),
+    VariantItem(Just(VARIANT (5, "num1", $vartype1))),
+    VariantItem(Nothing(OptionalType($vartype1))),
+    VariantItem(NULL)
+;
diff --git a/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_tuple_builtins_/formatted.sql b/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_tuple_builtins_/formatted.sql
new file mode 100644
index 0000000000..b1e21cda10
--- /dev/null
+++ b/yql/essentials/tests/sql/sql2yql/canondata/test_sql_format.test_expr-variant_tuple_builtins_/formatted.sql
@@ -0,0 +1,46 @@
+$vartype = Variant<Int32, Bool, String>;
+
+$handle_num = ($x) -> {
+    RETURN 2 * $x;
+};
+
+$handle_flag = ($x) -> {
+    RETURN If($x, 200, 10);
+};
+
+$handle_str = ($x) -> {
+    RETURN Unwrap(CAST(LENGTH($x) AS Int32));
+};
+
+$visitor = ($var) -> {
+    RETURN Visit($var, $handle_num, $handle_flag, $handle_str);
+};
+
+SELECT
+    $visitor(VARIANT (5, "0", $vartype)),
+    $visitor(Just(VARIANT (TRUE, "1", $vartype))),
+    $visitor(Just(VARIANT ("somestr", "2", $vartype))),
+    $visitor(Nothing(OptionalType($vartype))),
+    $visitor(NULL)
+;
+
+$visitor_def = ($var) -> {
+    RETURN VisitOrDefault($var, $handle_num, $handle_flag, 999);
+};
+
+SELECT
+    $visitor_def(VARIANT (5, "0", $vartype)),
+    $visitor_def(Just(VARIANT (TRUE, "1", $vartype))),
+    $visitor_def(Just(VARIANT ("somestr", "2", $vartype))),
+    $visitor_def(Nothing(OptionalType($vartype))),
+    $visitor_def(NULL)
+;
+
+$vartype1 = Variant<Int32, Int32, Int32>;
+
+SELECT
+    VariantItem(VARIANT (7, "1", $vartype1)),
+    VariantItem(Just(VARIANT (5, "0", $vartype1))),
+    VariantItem(Nothing(OptionalType($vartype1))),
+    VariantItem(NULL)
+;
diff --git a/yql/essentials/tests/sql/suites/expr/variant_builtins_opt.sql b/yql/essentials/tests/sql/suites/expr/variant_builtins_opt.sql
new file mode 100644
index 0000000000..443802fe56
--- /dev/null
+++ b/yql/essentials/tests/sql/suites/expr/variant_builtins_opt.sql
@@ -0,0 +1,26 @@
+$vartype = Variant<a: Optional<String>, b: Optional<String>>;
+
+$handle_a = ($x) -> { return CAST(($x || "1") AS Uint32); };
+$handle_b = ($x) -> { return CAST(($x || "2") AS Uint32); };
+
+$var_a = Variant("5", "a", $vartype);
+$var_b = Variant("6", "b", $vartype);
+
+SELECT
+    Visit(Just($var_a), $handle_a AS a, $handle_b AS b),
+    Visit(Just($var_b), $handle_a AS a, $handle_b AS b),
+    VisitOrDefault(Just($var_b), Just(777u), $handle_a AS a),
+    VariantItem(Just($var_b))
+;
+
+$vartype_t = Variant<Optional<String>, Optional<String>>;
+
+$var_1 = Variant("7", "0", $vartype_t);
+$var_2 = Variant("8", "1", $vartype_t);
+
+SELECT
+    Visit(Just($var_1), $handle_a, $handle_b),
+    Visit(Just($var_2), $handle_a, $handle_b),
+    VisitOrDefault(Just($var_2), $handle_a, Just(777u)),
+    VariantItem(Just($var_b))
+;
diff --git a/yql/essentials/tests/sql/suites/expr/variant_struct_builtins.sql b/yql/essentials/tests/sql/suites/expr/variant_struct_builtins.sql
new file mode 100644
index 0000000000..71a09810da
--- /dev/null
+++ b/yql/essentials/tests/sql/suites/expr/variant_struct_builtins.sql
@@ -0,0 +1,30 @@
+$vartype = Variant<num: Int32, flag: Bool, str: String>;
+$handle_num = ($x) -> { return 2 * $x; };
+$handle_flag = ($x) -> { return If($x, 200, 10); };
+$handle_str = ($x) -> { return Unwrap(CAST(LENGTH($x) AS Int32)); };
+
+$visitor = ($var) -> { return Visit($var, $handle_num AS num, $handle_flag AS flag, $handle_str AS str); };
+SELECT
+    $visitor(Variant(5, "num", $vartype)),
+    $visitor(Just(Variant(True, "flag", $vartype))),
+    $visitor(Just(Variant("somestr", "str", $vartype))),
+    $visitor(Nothing(OptionalType($vartype))),
+    $visitor(NULL)
+;
+
+$visitor_def = ($var) -> { return VisitOrDefault($var, 999, $handle_num AS num, $handle_flag AS flag); };
+SELECT
+    $visitor_def(Variant(5, "num", $vartype)),
+    $visitor_def(Just(Variant(True, "flag", $vartype))),
+    $visitor_def(Just(Variant("somestr", "str", $vartype))),
+    $visitor_def(Nothing(OptionalType($vartype))),
+    $visitor_def(NULL)
+;
+
+$vartype1 = Variant<num1: Int32, num2: Int32, num3: Int32>;
+SELECT
+    VariantItem(Variant(7, "num2", $vartype1)),
+    VariantItem(Just(Variant(5, "num1", $vartype1))),
+    VariantItem(Nothing(OptionalType($vartype1))),
+    VariantItem(NULL)
+;
\ No newline at end of file
diff --git a/yql/essentials/tests/sql/suites/expr/variant_tuple_builtins.sql b/yql/essentials/tests/sql/suites/expr/variant_tuple_builtins.sql
new file mode 100644
index 0000000000..35d1775708
--- /dev/null
+++ b/yql/essentials/tests/sql/suites/expr/variant_tuple_builtins.sql
@@ -0,0 +1,30 @@
+$vartype = Variant<Int32, Bool, String>;
+$handle_num = ($x) -> { return 2 * $x; };
+$handle_flag = ($x) -> { return If($x, 200, 10); };
+$handle_str = ($x) -> { return Unwrap(CAST(LENGTH($x) AS Int32)); };
+
+$visitor = ($var) -> { return Visit($var, $handle_num, $handle_flag, $handle_str); };
+SELECT
+    $visitor(Variant(5, "0", $vartype)),
+    $visitor(Just(Variant(True, "1", $vartype))),
+    $visitor(Just(Variant("somestr", "2", $vartype))),
+    $visitor(Nothing(OptionalType($vartype))),
+    $visitor(NULL)
+;
+
+$visitor_def = ($var) -> { return VisitOrDefault($var, $handle_num, $handle_flag, 999); };
+SELECT
+    $visitor_def(Variant(5, "0", $vartype)),
+    $visitor_def(Just(Variant(True, "1", $vartype))),
+    $visitor_def(Just(Variant("somestr", "2", $vartype))),
+    $visitor_def(Nothing(OptionalType($vartype))),
+    $visitor_def(NULL)
+;
+
+$vartype1 = Variant<Int32, Int32, Int32>;
+SELECT
+    VariantItem(Variant(7, "1", $vartype1)),
+    VariantItem(Just(Variant(5, "0", $vartype1))),
+    VariantItem(Nothing(OptionalType($vartype1))),
+    VariantItem(NULL)
+;
\ No newline at end of file