Fixing tuple/array literal parsing

src/Parsers/ExpressionElementParsers.cpp

@@ -1289,12 +1289,16 @@ bool ParserStringLiteral::parseImpl(Pos & pos, ASTPtr & node, Expected & expecte
 template <typename Collection>
 struct CollectionOfLiteralsLayer
 {
-    explicit CollectionOfLiteralsLayer(IParser::Pos & pos) : literal_begin(pos)
+    explicit CollectionOfLiteralsLayer(IParser::Pos & pos, TokenType closing_bracket_)
+        : literal_begin(pos)
+        , closing_bracket(closing_bracket_)
     {
+        pos.increaseDepth();
         ++pos;
     }
 
     IParser::Pos literal_begin;
+    TokenType closing_bracket;
     Collection arr;
 };
 
@@ -1305,8 +1309,7 @@ bool ParserCollectionOfLiterals<Collection>::parseImpl(Pos & pos, ASTPtr & node,
         return false;
 
     std::vector<CollectionOfLiteralsLayer<Collection>> layers;
-    layers.emplace_back(pos);
-    pos.increaseDepth();
+    layers.emplace_back(pos, closing_bracket);
 
     ParserLiteral literal_p;
 
@@ -1314,13 +1317,22 @@ bool ParserCollectionOfLiterals<Collection>::parseImpl(Pos & pos, ASTPtr & node,
     {
         if (!layers.back().arr.empty())
         {
-            if (pos->type == closing_bracket)
+            if (pos->type == layers.back().closing_bracket)
             {
                 std::shared_ptr<ASTLiteral> literal;
 
-                /// Parse one-element tuples (e.g. (1)) later as single values for backward compatibility.
+                // /// Parse one-element tuples (e.g. (1)) later as single values for backward compatibility.
                 if (std::is_same_v<Collection, Tuple> && layers.back().arr.size() == 1)
+                {
+                    if (layers.size() > 1)
+                    {
+                        layers[layers.size() - 2].arr.push_back(layers.back().arr[0]);
+                        layers.pop_back();
+                        pos.decreaseDepth();
+                        continue;
+                    }
                     return false;
+                }
 
                 literal = std::make_shared<ASTLiteral>(std::move(layers.back().arr));
                 literal->begin = layers.back().literal_begin;
@@ -1360,8 +1372,17 @@ bool ParserCollectionOfLiterals<Collection>::parseImpl(Pos & pos, ASTPtr & node,
         }
         else if (pos->type == opening_bracket)
         {
-            layers.emplace_back(pos);
-            pos.increaseDepth();
+            layers.emplace_back(pos, closing_bracket);
+        }
+        else if (pos->type == TokenType::BareWord && std::string_view(pos->begin, pos->end) == FunctionName<Collection>::value)
+        {
+            ++pos;
+            if (pos.isValid() && pos->type == TokenType::OpeningRoundBracket)
+            {
+                layers.emplace_back(pos, TokenType::ClosingRoundBracket);
+            }
+            else
+                return false;
         }
         else
             return false;

src/Parsers/ExpressionElementParsers.h

@@ -313,6 +313,12 @@ protected:
 private:
     TokenType opening_bracket;
     TokenType closing_bracket;
+
+    template <typename> struct FunctionName;
+    template <> struct FunctionName<Array> { static constexpr auto value = "array"; };
+    template <> struct FunctionName<Tuple> { static constexpr auto value = "tuple"; };
+
+    std::string_view function_name = FunctionName<Collection>::value;
 };
 
 /// A tuple of literals with same type.

src/Parsers/tests/gtest_Parser.cpp

@@ -662,3 +662,49 @@ INSTANTIATE_TEST_SUITE_P(
                 "WITH\n    table_1 AS\n    (\n        SELECT\n            country,\n            city,\n            c + some_derived_value AS _expr_1\n        FROM matches\n        WHERE start_date > toDate('2023-05-30')\n    ),\n    table_0 AS\n    (\n        SELECT\n            country,\n            city,\n            AVG(_expr_1) AS _expr_0,\n            MAX(_expr_1) AS aggr\n        FROM table_1\n        WHERE _expr_1 > 0\n        GROUP BY\n            country,\n            city\n    )\nSELECT\n    country,\n    city,\n    _expr_0,\n    aggr,\n    CONCAT(city, ' in ', country) AS place,\n    LEFT(country, 2) AS country_code\nFROM table_0\nORDER BY\n    aggr ASC,\n    country DESC\nLIMIT 20",
             },
         })));
+
+namespace DB { std::ostream & operator<<(std::ostream & stream, const Field & field) { return stream << field.dump(); } }
+
+TEST(ParserTest, parseTupleLiterals)
+try
+{
+    ParserTupleOfLiterals parser;
+
+    auto parse_tuple = [&](std::string_view text) -> std::optional<Tuple>
+    {
+        try
+        {
+            auto ast = parseQuery(parser, text.begin(), text.end(), 0, 0, 0);
+            const auto * literal = typeid_cast<const ASTLiteral *>(ast.get());
+            if (!literal || literal->value.getType() != Field::Types::Tuple)
+                return {};
+            return literal->value.safeGet<Tuple>();
+        }
+        catch (const DB::Exception & e)
+        {
+            std::cerr << e.displayText() << std::endl;
+            return {};
+        }
+    };
+
+    const auto & tuple = parse_tuple("((1, 2), (3, 4))");
+    ASSERT_TRUE(tuple && tuple->size() == 2);
+
+    std::vector<std::string_view> test_cases = {
+        // "((1, 2,), (3, 4,),)",
+        // "  (    (\t\t 1  \r\n ,  2  ,\n ) \t\t,   (  3  ,  4 \t, ) ,  )   ",
+        "(((1, 2)), (3, 4))",
+        "(((1), 2), (3, 4))",
+        "(tuple(1, 2), (3, 4))",
+    };
+    for (size_t i = 0; i < test_cases.size(); ++i)
+    {
+        SCOPED_TRACE(fmt::format("Test case #{}: {}", i + 1, test_cases[i]));
+        EXPECT_EQ(tuple, parse_tuple(test_cases[i]));
+    }
+}
+catch (...)
+{
+    std::cerr << getCurrentExceptionMessage(true) << std::endl;
+    throw;
+}