Merge pull request #19 from Progmasoft/feature/yyjson-pugixml

Read and write JSON with yyjson and JUnit XML with pugixml

1 files changed, 241 insertions, 700 deletions

diff --git a/extras/catch_amalgamated.cpp b/extras/catch_amalgamated.cpp
index 0f336b53..a9cdb04b 100644
--- a/extras/catch_amalgamated.cpp
+++ b/extras/catch_amalgamated.cpp
@@ -7,7 +7,7 @@
 // SPDX-License-Identifier: BSL-1.0
 
 //  Catch3 v0.3.0, on the Catch2 v3.16.1 engine
-//  Generated: 2026-10-25 02:37:10.065190
+//  Generated: 2026-10-25 13:52:54.556111
 //  ----------------------------------------------------------
 //  This file is an amalgamation of multiple different files.
 //  You probably shouldn't edit it directly.
@@ -658,9 +658,6 @@ namespace Progmasoft::Catch3::Runner
 
     private:
         void
-        Write(std::string &output, int indent, int depth) const;
-
-        void
         Destroy() noexcept;
 
         void
@@ -8976,6 +8973,8 @@ namespace Progmasoft::Catch3
 // Copyright (c) 2026 Progmasoft.
 // SPDX-License-Identifier: MPL-2.0 WITH AdditionRef-Progmasoft-Exception-1.1
 
+#include "catch_amalgamated_third_party.hpp"
+
 #include <ostream>
 #include <sstream>
 #include <string_view>
@@ -9055,63 +9054,50 @@ namespace Progmasoft::Catch3
                    (value >= 0x10000 && value <= 0x10FFFF);
         }
 
-        void
-        WriteEscaped(std::string_view value, std::ostream &output, bool attribute)
+        /// The text as XML can hold it: every byte that is not part of a
+        /// well-formed character XML allows becomes U+FFFD, replaced and not
+        /// dropped, so the reader sees that something was there. pugixml
+        /// escapes the rest.
+        std::string
+        XmlText(std::string_view value)
         {
+            std::string result;
+            result.reserve(value.size());
             for (std::size_t index = 0; index < value.size();)
             {
                 const DecodedCharacter character = DecodeUtf8(value, index);
                 if (character.length == 0 || !IsXmlCharacter(character.value))
                 {
-                    // A character XML cannot hold is replaced, not dropped,
-                    // so the reader sees that something was there.
-                    output << "&#xFFFD;";
+                    result += "\xEF\xBF\xBD";
                     ++index;
                     continue;
                 }
-                if (character.value < 0x80)
-                {
-                    switch (static_cast<char>(character.value))
-                    {
-                        case '&':
-                            output << "&amp;";
-                            break;
-                        case '<':
-                            output << "&lt;";
-                            break;
-                        case '>':
-                            output << "&gt;";
-                            break;
-                        case '"':
-                            output << (attribute ? "&quot;" : "\"");
-                            break;
-                        case '\'':
-                            output << (attribute ? "&apos;" : "'");
-                            break;
-                        case '\n':
-                            output << (attribute ? "&#10;" : "\n");
-                            break;
-                        default:
-                            output.put(static_cast<char>(character.value));
-                    }
-                }
-                else
-                {
-                    output.write(value.data() + index,
-                                 static_cast<std::streamsize>(character.length));
-                }
+                result.append(value.data() + index, character.length);
                 index += character.length;
             }
+            return result;
         }
 
         void
-        WriteAttribute(std::ostream &output,
-                       std::string_view name,
+        AddAttribute(pugi::xml_node node,
+                     const char *name,
+                     std::string_view value)
+        {
+            node.append_attribute(name).set_value(XmlText(value).c_str());
+        }
+
+        void
+        AddText(pugi::xml_node node, std::string_view value)
+        {
+            node.text().set(XmlText(value).c_str());
+        }
+
+        void
+        AddTextElement(pugi::xml_node parent,
+                       const char *name,
                        std::string_view value)
         {
-            output << ' ' << name << "=\"";
-            WriteEscaped(value, output, true);
-            output << '"';
+            AddText(parent.append_child(name), value);
         }
 
         std::string
@@ -9125,27 +9111,6 @@ namespace Progmasoft::Catch3
                    "." + fraction;
         }
 
-        void
-        WriteIndent(std::ostream &output, unsigned level)
-        {
-            for (unsigned index = 0; index < level; ++index)
-            {
-                output << "  ";
-            }
-        }
-
-        void
-        WriteTextElement(std::ostream &output,
-                         unsigned indent,
-                         std::string_view name,
-                         std::string_view value)
-        {
-            WriteIndent(output, indent);
-            output << '<' << name << '>';
-            WriteEscaped(value, output, false);
-            output << "</" << name << ">\n";
-        }
-
         std::string
         Output(const Attempt &attempt, bool errors)
         {
@@ -9159,27 +9124,22 @@ namespace Progmasoft::Catch3
         /// An earlier attempt: `<rerunFailure>` before a final failure,
         /// `<flakyFailure>` before a final pass.
         void
-        WriteEarlierAttempt(std::ostream &output,
-                            const Attempt &attempt,
-                            std::string_view element)
-        {
-            WriteIndent(output, 3);
-            output << '<' << element;
-            WriteAttribute(output, "message", SummarizeFailure(attempt));
-            WriteAttribute(output, "type", CategoryName(attempt.category));
-            output << ">\n";
-            WriteTextElement(output, 4, "stackTrace", DescribeFailure(attempt));
+        AddEarlierAttempt(pugi::xml_node testCase,
+                          const Attempt &attempt,
+                          const char *element)
+        {
+            pugi::xml_node node = testCase.append_child(element);
+            AddAttribute(node, "message", SummarizeFailure(attempt));
+            AddAttribute(node, "type", CategoryName(attempt.category));
+            AddTextElement(node, "stackTrace", DescribeFailure(attempt));
             if (!attempt.standardOutput.empty())
             {
-                WriteTextElement(
-                    output, 4, "system-out", Output(attempt, false));
+                AddTextElement(node, "system-out", Output(attempt, false));
             }
             if (!Output(attempt, true).empty())
             {
-                WriteTextElement(output, 4, "system-err", Output(attempt, true));
+                AddTextElement(node, "system-err", Output(attempt, true));
             }
-            WriteIndent(output, 3);
-            output << "</" << element << ">\n";
         }
 
         std::string
@@ -9200,23 +9160,21 @@ namespace Progmasoft::Catch3
         }
 
         void
-        WriteTestCase(std::ostream &output,
-                      const TestResult &test,
-                      std::string_view suiteName)
-        {
-            WriteIndent(output, 2);
-            output << "<testcase";
-            WriteAttribute(output,
-                           "classname",
-                           test.className.empty() ? suiteName : test.className);
-            WriteAttribute(output, "name", test.name);
-            WriteAttribute(output, "time", JUnitSeconds(test.DurationMicroseconds()));
+        AddTestCase(pugi::xml_node suite,
+                    const TestResult &test,
+                    std::string_view suiteName)
+        {
+            pugi::xml_node node = suite.append_child("testcase");
+            AddAttribute(node,
+                         "classname",
+                         test.className.empty() ? suiteName : test.className);
+            AddAttribute(node, "name", test.name);
+            AddAttribute(node, "time", JUnitSeconds(test.DurationMicroseconds()));
             if (!test.file.empty())
             {
-                WriteAttribute(output, "file", test.file);
-                WriteAttribute(output, "line", std::to_string(test.line));
+                AddAttribute(node, "file", test.file);
+                AddAttribute(node, "line", std::to_string(test.line));
             }
-            output << ">\n";
 
             const Attempt *last =
                 test.attempts.empty() ? nullptr : &test.attempts.back();
@@ -9226,12 +9184,10 @@ namespace Progmasoft::Catch3
                 const bool error = test.outcome != Outcome::kFailed ||
                                    last->category ==
                                        FailureCategory::kInfrastructure;
-                const std::string_view element = error ? "error" : "failure";
-                WriteIndent(output, 3);
-                output << '<' << element;
-                WriteAttribute(output, "message", SummarizeFailure(*last));
-                WriteAttribute(output, "type", CategoryName(test.category));
-                output << '>';
+                pugi::xml_node failure =
+                    node.append_child(error ? "error" : "failure");
+                AddAttribute(failure, "message", SummarizeFailure(*last));
+                AddAttribute(failure, "type", CategoryName(test.category));
                 std::string details = DescribeFailure(*last);
                 for (const auto &finding : test.analysis)
                 {
@@ -9241,18 +9197,15 @@ namespace Progmasoft::Catch3
                 {
                     details += "replay: " + test.replayCommand + "\n";
                 }
-                WriteEscaped(details, output, false);
-                output << "</" << element << ">\n";
+                AddText(failure, details);
             }
             else if (test.outcome == Outcome::kSkipped ||
                      test.outcome == Outcome::kBlocked ||
                      test.outcome == Outcome::kNotRun ||
                      test.outcome == Outcome::kUpToDate)
             {
-                WriteIndent(output, 3);
-                output << "<skipped";
-                WriteAttribute(output, "message", SkipReason(test));
-                output << "/>\n";
+                AddAttribute(
+                    node.append_child("skipped"), "message", SkipReason(test));
             }
             // Every earlier failed attempt, so retries stay visible.
             for (std::size_t index = 0; index + 1 < test.attempts.size();
@@ -9263,20 +9216,36 @@ namespace Progmasoft::Catch3
                 {
                     continue;
                 }
-                WriteEarlierAttempt(output,
-                                    attempt,
-                                    failedRun ? "rerunFailure" : "flakyFailure");
+                AddEarlierAttempt(node,
+                                  attempt,
+                                  failedRun ? "rerunFailure" : "flakyFailure");
             }
             if (last != nullptr && !last->standardOutput.empty())
             {
-                WriteTextElement(output, 3, "system-out", Output(*last, false));
+                AddTextElement(node, "system-out", Output(*last, false));
             }
             if (last != nullptr && !Output(*last, true).empty())
             {
-                WriteTextElement(output, 3, "system-err", Output(*last, true));
+                AddTextElement(node, "system-err", Output(*last, true));
             }
-            WriteIndent(output, 2);
-            output << "</testcase>\n";
+        }
+
+        void
+        AddCounts(pugi::xml_node node,
+                  const RunResult &run,
+                  const RunSummary &summary)
+        {
+            AddAttribute(node, "name", run.binary);
+            AddAttribute(node, "tests", std::to_string(summary.tests));
+            AddAttribute(node, "failures", std::to_string(summary.failed));
+            AddAttribute(node,
+                         "errors",
+                         std::to_string(summary.crashed + summary.timedOut));
+            AddAttribute(node,
+                         "skipped",
+                         std::to_string(summary.skipped + summary.blocked +
+                                        summary.notRun + summary.upToDate));
+            AddAttribute(node, "time", JUnitSeconds(run.wallMicroseconds));
         }
     } // namespace
 
@@ -9284,38 +9253,21 @@ namespace Progmasoft::Catch3
     JUnitXmlWriter::Write(const RunResult &run, std::ostream &output)
     {
         const RunSummary summary = Summarize(run);
-        const std::size_t errors = summary.crashed + summary.timedOut;
-        const std::size_t failures = summary.failed;
-        const std::size_t skipped =
-            summary.skipped + summary.blocked + summary.notRun +
-            summary.upToDate;
-        const std::string time = JUnitSeconds(run.wallMicroseconds);
-        output << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<testsuites";
-        WriteAttribute(output, "name", run.binary);
-        WriteAttribute(output, "tests", std::to_string(summary.tests));
-        WriteAttribute(output, "failures", std::to_string(failures));
-        WriteAttribute(output, "errors", std::to_string(errors));
-        WriteAttribute(output, "skipped", std::to_string(skipped));
-        WriteAttribute(output, "time", time);
-        output << ">\n";
-        WriteIndent(output, 1);
-        output << "<testsuite";
-        WriteAttribute(output, "name", run.binary);
-        WriteAttribute(output, "tests", std::to_string(summary.tests));
-        WriteAttribute(output, "failures", std::to_string(failures));
-        WriteAttribute(output, "errors", std::to_string(errors));
-        WriteAttribute(output, "skipped", std::to_string(skipped));
-        WriteAttribute(output, "time", time);
-        output << ">\n";
-        WriteIndent(output, 2);
-        output << "<properties>\n";
-        const auto property = [&](std::string_view name,
-                                  const std::string &value) {
-            WriteIndent(output, 3);
-            output << "<property";
-            WriteAttribute(output, "name", name);
-            WriteAttribute(output, "value", value);
-            output << "/>\n";
+        pugi::xml_document document;
+        pugi::xml_node declaration =
+            document.append_child(pugi::node_declaration);
+        declaration.append_attribute("version").set_value("1.0");
+        declaration.append_attribute("encoding").set_value("UTF-8");
+
+        pugi::xml_node suites = document.append_child("testsuites");
+        AddCounts(suites, run, summary);
+        pugi::xml_node suite = suites.append_child("testsuite");
+        AddCounts(suite, run, summary);
+        pugi::xml_node properties = suite.append_child("properties");
+        const auto property = [&](const char *name, const std::string &value) {
+            pugi::xml_node node = properties.append_child("property");
+            AddAttribute(node, "name", name);
+            AddAttribute(node, "value", value);
         };
         property("random-seed", std::to_string(run.seed));
         property("workers", std::to_string(run.workers));
@@ -9327,14 +9279,12 @@ namespace Progmasoft::Catch3
         }
         property("flaky", std::to_string(summary.flaky));
         property("quarantined", std::to_string(summary.quarantined));
-        WriteIndent(output, 2);
-        output << "</properties>\n";
         for (const auto &test : run.tests)
         {
-            WriteTestCase(output, test, run.binary);
+            AddTestCase(suite, test, run.binary);
         }
-        WriteIndent(output, 1);
-        output << "</testsuite>\n</testsuites>\n";
+
+        document.save(output, "  ", pugi::format_indent, pugi::encoding_utf8);
         return static_cast<bool>(output);
     }
 
@@ -12180,12 +12130,9 @@ namespace Progmasoft::Catch3::Runner
 // Copyright (c) 2026 Progmasoft.
 // SPDX-License-Identifier: MPL-2.0 WITH AdditionRef-Progmasoft-Exception-1.1
 
-#include <clocale>
+
 #include <cmath>
-#include <cstdio>
 #include <cstdlib>
-#include <limits>
-#include <optional>
 
 namespace Progmasoft::Catch3::Runner
 {
@@ -12223,481 +12170,160 @@ namespace Progmasoft::Catch3::Runner
         }
 
         /// Documents nested deeper than this are refused, so a hostile or
-        /// broken file cannot exhaust the stack of the parser.
+        /// broken file cannot exhaust the stack while it is converted.
         constexpr int kMaximumDepth = 256;
 
-        void
-        AppendUtf8(std::string &output, std::uint32_t codePoint)
-        {
-            if (codePoint < 0x80)
-            {
-                output.push_back(static_cast<char>(codePoint));
-            }
-            else if (codePoint < 0x800)
-            {
-                output.push_back(static_cast<char>(0xC0 | (codePoint >> 6)));
-                output.push_back(static_cast<char>(0x80 | (codePoint & 0x3F)));
-            }
-            else if (codePoint < 0x10000)
-            {
-                output.push_back(static_cast<char>(0xE0 | (codePoint >> 12)));
-                output.push_back(
-                    static_cast<char>(0x80 | ((codePoint >> 6) & 0x3F)));
-                output.push_back(static_cast<char>(0x80 | (codePoint & 0x3F)));
-            }
-            else
-            {
-                output.push_back(static_cast<char>(0xF0 | (codePoint >> 18)));
-                output.push_back(
-                    static_cast<char>(0x80 | ((codePoint >> 12) & 0x3F)));
-                output.push_back(
-                    static_cast<char>(0x80 | ((codePoint >> 6) & 0x3F)));
-                output.push_back(static_cast<char>(0x80 | (codePoint & 0x3F)));
-            }
-        }
+        /// Strings are bytes: test names and output need not be UTF-8, and
+        /// they come back as they were written.
+        constexpr yyjson_read_flag kReadFlags =
+            YYJSON_READ_ALLOW_INVALID_UNICODE;
 
-        /// Reads a JSON number exactly. The grammar is checked here; strtod
-        /// does the rounding, with the point replaced by the decimal
-        /// separator of the current locale, which a test may have changed.
-        std::optional<double>
-        ToDouble(std::string_view digits)
-        {
-            std::size_t index = 0;
-            const auto skipDigits = [&] {
-                const std::size_t start = index;
-                while (index < digits.size() && digits[index] >= '0' &&
-                       digits[index] <= '9')
-                {
-                    ++index;
-                }
-                return index > start;
-            };
-            if (index < digits.size() && digits[index] == '-')
-            {
-                ++index;
-            }
-            if (!skipDigits())
-            {
-                return std::nullopt;
-            }
-            std::size_t point = std::string_view::npos;
-            if (index < digits.size() && digits[index] == '.')
-            {
-                point = index++;
-                if (!skipDigits())
-                {
-                    return std::nullopt;
-                }
-            }
-            if (index < digits.size() &&
-                (digits[index] == 'e' || digits[index] == 'E'))
-            {
-                ++index;
-                if (index < digits.size() &&
-                    (digits[index] == '+' || digits[index] == '-'))
-                {
-                    ++index;
-                }
-                if (!skipDigits())
-                {
-                    return std::nullopt;
-                }
-            }
-            if (index != digits.size())
-            {
-                return std::nullopt;
-            }
-            std::string copy{digits};
-            if (point != std::string_view::npos)
-            {
-                const char *separator = std::localeconv()->decimal_point;
-                copy.replace(point,
-                             1,
-                             separator == nullptr || *separator == '\0'
-                                 ? "."
-                                 : separator);
-            }
-            return std::strtod(copy.c_str(), nullptr);
-        }
+        /// JSON has no infinities; null is the conventional stand-in.
+        constexpr yyjson_write_flag kWriteFlags =
+            YYJSON_WRITE_ALLOW_INVALID_UNICODE |
+            YYJSON_WRITE_INF_AND_NAN_AS_NULL;
 
-        class Parser final
+        /// Converts a value of yyjson's tree; false when it is nested too
+        /// deeply.
+        bool
+        FromYyjson(yyjson_val *value, int depth, JsonValue &result)
         {
-        public:
-            explicit Parser(std::string_view text)
-                : text_{text}
+            if (depth > kMaximumDepth)
             {
+                return false;
             }
-
-            Expected<JsonValue>
-            ParseDocument()
-            {
-                SkipWhitespace();
-                auto value = ParseValue(0);
-                if (!value)
-                {
-                    return value;
-                }
-                SkipWhitespace();
-                if (position_ != text_.size())
-                {
-                    return Fail("unexpected text after the value");
-                }
-                return value;
-            }
-
-        private:
-            Error
-            Fail(const std::string &message) const
-            {
-                return Error{"invalid JSON at offset " +
-                             std::to_string(position_) + ": " + message};
-            }
-
-            void
-            SkipWhitespace()
+            switch (yyjson_get_type(value))
             {
-                while (position_ < text_.size())
+                case YYJSON_TYPE_BOOL:
+                    result = JsonValue{yyjson_get_bool(value)};
+                    return true;
+                case YYJSON_TYPE_NUM:
+                    result = JsonValue{yyjson_get_num(value)};
+                    return true;
+                case YYJSON_TYPE_STR:
+                    result = JsonValue{std::string_view{
+                        yyjson_get_str(value), yyjson_get_len(value)}};
+                    return true;
+                case YYJSON_TYPE_ARR:
                 {
-                    const char character = text_[position_];
-                    if (character != ' ' && character != '\t' &&
-                        character != '\n' && character != '\r')
+                    JsonValue array = JsonValue::Array();
+                    auto &items = array.MutableItems();
+                    items.reserve(yyjson_arr_size(value));
+                    yyjson_arr_iter iterator = yyjson_arr_iter_with(value);
+                    while (yyjson_val *item = yyjson_arr_iter_next(&iterator))
                     {
-                        return;
+                        items.emplace_back();
+                        if (!FromYyjson(item, depth + 1, items.back()))
+                        {
+                            return false;
+                        }
                     }
-                    ++position_;
-                }
-            }
-
-            bool
-            Consume(std::string_view word)
-            {
-                if (text_.substr(position_, word.size()) == word)
-                {
-                    position_ += word.size();
+                    result = std::move(array);
                     return true;
                 }
-                return false;
-            }
-
-            Expected<JsonValue>
-            ParseValue(int depth)
-            {
-                if (depth > kMaximumDepth)
-                {
-                    return Fail("nested too deeply");
-                }
-                if (position_ >= text_.size())
-                {
-                    return Fail("a value was expected");
-                }
-                const char character = text_[position_];
-                if (character == '{')
-                {
-                    return ParseObject(depth);
-                }
-                if (character == '[')
-                {
-                    return ParseArray(depth);
-                }
-                if (character == '"')
+                case YYJSON_TYPE_OBJ:
                 {
-                    auto text = ParseString();
-                    if (!text)
+                    JsonValue object = JsonValue::Object();
+                    auto &members = object.MutableMembers();
+                    members.reserve(yyjson_obj_size(value));
+                    yyjson_obj_iter iterator = yyjson_obj_iter_with(value);
+                    while (yyjson_val *key = yyjson_obj_iter_next(&iterator))
                     {
-                        return text.GetError();
+                        members.emplace_back(
+                            std::string{yyjson_get_str(key),
+                                        yyjson_get_len(key)},
+                            JsonValue{});
+                        if (!FromYyjson(yyjson_obj_iter_get_val(key),
+                                        depth + 1,
+                                        members.back().second))
+                        {
+                            return false;
+                        }
                     }
-                    return JsonValue{std::move(*text)};
-                }
-                if (Consume("true"))
-                {
-                    return JsonValue{true};
-                }
-                if (Consume("false"))
-                {
-                    return JsonValue{false};
-                }
-                if (Consume("null"))
-                {
-                    return JsonValue{};
+                    result = std::move(object);
+                    return true;
                 }
-                return ParseNumber();
+                default:
+                    result = JsonValue{};
+                    return true;
             }
+        }
 
-            Expected<JsonValue>
-            ParseNumber()
+        /// A whole number within the exact range of a double is written as
+        /// an integer, anything else as the shortest text that reads back as
+        /// the same double.
+        yyjson_mut_val *
+        ToYyjsonNumber(yyjson_mut_doc *document, double value)
+        {
+            if (std::isfinite(value) &&
+                std::fabs(value) < 9.007199254740992e15 &&
+                value == std::trunc(value))
             {
-                const std::size_t start = position_;
-                if (position_ < text_.size() && text_[position_] == '-')
-                {
-                    ++position_;
-                }
-                while (position_ < text_.size())
-                {
-                    const char character = text_[position_];
-                    const bool numeric =
-                        (character >= '0' && character <= '9') ||
-                        character == '.' || character == 'e' ||
-                        character == 'E' || character == '+' ||
-                        character == '-';
-                    if (!numeric)
-                    {
-                        break;
-                    }
-                    ++position_;
-                }
-                if (position_ == start)
-                {
-                    return Fail("a value was expected");
-                }
-                const std::string_view digits =
-                    text_.substr(start, position_ - start);
-                const auto value = ToDouble(digits);
-                if (!value)
-                {
-                    position_ = start;
-                    return Fail("malformed number");
-                }
-                return JsonValue{*value};
+                return yyjson_mut_sint(document,
+                                       static_cast<std::int64_t>(value));
             }
+            return yyjson_mut_real(document, value);
+        }
 
-            Expected<std::uint32_t>
-            ParseHexQuad()
+        /// Builds yyjson's tree of a value. Strings are referenced, not
+        /// copied: the tree is written before `value` can change.
+        yyjson_mut_val *
+        ToYyjson(yyjson_mut_doc *document, const JsonValue &value)
+        {
+            switch (value.GetKind())
             {
-                if (position_ + 4 > text_.size())
+                case JsonValue::Kind::kNull:
+                    return yyjson_mut_null(document);
+                case JsonValue::Kind::kBoolean:
+                    return yyjson_mut_bool(document, value.AsBoolean());
+                case JsonValue::Kind::kNumber:
+                    return ToYyjsonNumber(document, value.AsNumber());
+                case JsonValue::Kind::kString:
                 {
-                    return Fail("truncated \\u escape");
+                    const std::string &text = value.AsString();
+                    return yyjson_mut_strn(document, text.data(), text.size());
                 }
-                std::uint32_t value = 0;
-                for (int index = 0; index < 4; ++index)
+                case JsonValue::Kind::kArray:
                 {
-                    const char character = text_[position_++];
-                    value <<= 4;
-                    if (character >= '0' && character <= '9')
-                    {
-                        value |= static_cast<std::uint32_t>(character - '0');
-                    }
-                    else if (character >= 'a' && character <= 'f')
+                    yyjson_mut_val *array = yyjson_mut_arr(document);
+                    for (const auto &item : value.Items())
                     {
-                        value |=
-                            static_cast<std::uint32_t>(character - 'a' + 10);
-                    }
-                    else if (character >= 'A' && character <= 'F')
-                    {
-                        value |=
-                            static_cast<std::uint32_t>(character - 'A' + 10);
-                    }
-                    else
-                    {
-                        return Fail("malformed \\u escape");
-                    }
-                }
-                return value;
-            }
-
-            Expected<std::string>
-            ParseString()
-            {
-                ++position_; // The opening quote.
-                std::string result;
-                while (position_ < text_.size())
-                {
-                    const char character = text_[position_++];
-                    if (character == '"')
-                    {
-                        return result;
-                    }
-                    if (static_cast<unsigned char>(character) < 0x20)
-                    {
-                        return Fail("control character in a string");
-                    }
-                    if (character != '\\')
-                    {
-                        result.push_back(character);
-                        continue;
-                    }
-                    if (position_ >= text_.size())
-                    {
-                        break;
-                    }
-                    const char escape = text_[position_++];
-                    switch (escape)
-                    {
-                        case '"':
-                        case '\\':
-                        case '/':
-                            result.push_back(escape);
-                            break;
-                        case 'b':
-                            result.push_back('\b');
-                            break;
-                        case 'f':
-                            result.push_back('\f');
-                            break;
-                        case 'n':
-                            result.push_back('\n');
-                            break;
-                        case 'r':
-                            result.push_back('\r');
-                            break;
-                        case 't':
-                            result.push_back('\t');
-                            break;
-                        case 'u':
-                        {
-                            auto high = ParseHexQuad();
-                            if (!high)
-                            {
-                                return high.GetError();
-                            }
-                            std::uint32_t codePoint = *high;
-                            if (codePoint >= 0xD800 && codePoint <= 0xDBFF &&
-                                Consume("\\u"))
-                            {
-                                auto low = ParseHexQuad();
-                                if (!low)
-                                {
-                                    return low.GetError();
-                                }
-                                if (*low >= 0xDC00 && *low <= 0xDFFF)
-                                {
-                                    codePoint = 0x10000 +
-                                                ((codePoint - 0xD800) << 10) +
-                                                (*low - 0xDC00);
-                                }
-                            }
-                            AppendUtf8(result, codePoint);
-                            break;
-                        }
-                        default:
-                            return Fail("unknown escape");
+                        yyjson_mut_arr_append(array, ToYyjson(document, item));
                     }
-                }
-                return Fail("unterminated string");
-            }
-
-            Expected<JsonValue>
-            ParseArray(int depth)
-            {
-                ++position_;
-                JsonValue array = JsonValue::Array();
-                SkipWhitespace();
-                if (Consume("]"))
-                {
                     return array;
                 }
-                while (true)
+                case JsonValue::Kind::kObject:
                 {
-                    SkipWhitespace();
-                    auto item = ParseValue(depth + 1);
-                    if (!item)
+                    yyjson_mut_val *object = yyjson_mut_obj(document);
+                    for (const auto &[name, member] : value.Members())
                     {
-                        return item;
+                        yyjson_mut_obj_add(
+                            object,
+