Manager: Switch to own JSON parser, remove nlohmann/json

The .end() returns an iterator one past the last pair, so it would
always add a comma after the last member.

README.org

@@ -105,7 +105,6 @@ manafiles will make sure that the contents of the block are commented.
 - (make) ~cmake~
 - (make) ~git~
 - (make) ~gzip~
-- (make) ~nlohmann-json~ [[https://archlinux.org/packages/community/any/nlohmann-json/][arch]], [[https://packages.debian.org/search?keywords=nlohmann-json][debian]], [[https://packages.ubuntu.com/search?keywords=nlohmann-json][ubuntu]]
 - (optional) ~grep~
 - (optional) ~pacman~ + ~pacman-contrib~
 - (optional) ~apt~ + ~dpkg~

src/config.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <cassert>    // assert
 #include <csignal>    // raise
 #include <cstdio>     // fprintf
 #include <filesystem> // current_path, recursive_directory
@@ -11,9 +12,8 @@
 #include <string>
 #include <vector>
 
-#include <nlohmann/json.hpp>
-
 #include "config.h"
+#include "util/json/value.h"
 
 Config::Config(s)
 	: m_workingDirectory(std::filesystem::current_path())
@@ -51,7 +51,7 @@ void Config::parseConfigFile()
 		return;
 	}
 
-	nlohmann::json json;
+	Json::Value json;
 
 	std::ifstream file(m_config);
 	if (!file.is_open()) {
@@ -72,21 +72,23 @@ void Config::parseConfigFile()
 
 // -----------------------------------------
 
-void to_json(nlohmann::json& object, const Settings& settings)
+void toJson(Json::Value& json, const Settings& settings)
 {
-	object = nlohmann::json {
+	json = Json::Value {
 		{ "ignorePatterns", settings.ignorePatterns },
 		{ "systemPatterns", settings.systemPatterns }
 	};
 }
 
-void from_json(const nlohmann::json& object, Settings& settings)
+void fromJson(const Json::Value& json, Settings& settings)
 {
-	if (object.find("ignorePatterns") != object.end()) {
-		object.at("ignorePatterns").get_to(settings.ignorePatterns);
+	assert(json.type() == Json::Value::Type::Object);
+
+	if (json.exists("ignorePatterns")) {
+		json.at("ignorePatterns").getTo(settings.ignorePatterns);
 	}
 
-	if (object.find("systemPatterns") != object.end()) {
-		object.at("systemPatterns").get_to(settings.systemPatterns);
+	if (json.exists("systemPatterns")) {
+		json.at("systemPatterns").getTo(settings.systemPatterns);
 	}
 }

src/config.h

@@ -12,9 +12,8 @@
 #include <string>
 #include <vector>
 
-#include "nlohmann/json.hpp"
-
 #include "util/singleton.h"
+#include "util/json/value.h"
 
 struct Settings {
 	std::vector<std::string> ignorePatterns {
@@ -64,9 +63,9 @@ private:
 
 // -----------------------------------------
 
-// nlohmann::json arbitrary type conversion functions
+// Json arbitrary type conversion functions
 
-void to_json(nlohmann::json& object, const Settings& settings);
-void from_json(const nlohmann::json& object, Settings& settings);
+void toJson(Json::Value& object, const Settings& settings);
+void fromJson(const Json::Value& object, Settings& settings);
 
 #endif // CONFIG_H

src/util/json/array.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "util/json/array.h"
+#include "util/json/value.h"
+
+namespace Json {
+
+void Array::emplace_back(Value element)
+{
+	m_elements.emplace_back(std::move(element));
+}
+
+Value& Array::operator[](size_t index)
+{
+	if (index + 1 > m_elements.size()) {
+		m_elements.resize(index + 1);
+	}
+
+	return m_elements[index];
+}
+
+} // namespace Json

src/util/json/array.h

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_ARRAY_H
+#define JSON_ARRAY_H
+
+#include <utility> // move
+#include <vector>
+
+#include "util/json/parser.h"
+
+namespace Json {
+
+class Value;
+
+class Array {
+public:
+	Array() {}
+	virtual ~Array() {}
+
+	Array(const std::vector<Value>& elements)
+		: m_elements(elements)
+	{}
+
+	Array(const Array& other)
+		: m_elements(other.m_elements)
+	{
+	}
+
+	void emplace_back(Value element);
+	void reserve(size_t size) { m_elements.reserve(size); }
+
+	Value& operator[](size_t index);
+
+	Value& at(size_t index) { return m_elements.at(index); }
+	const Value& at(size_t index) const { return m_elements.at(index); }
+
+	size_t size() const { return m_elements.size(); }
+	const std::vector<Value>& elements() const { return m_elements; }
+
+private:
+	std::vector<Value> m_elements;
+};
+
+} // namespace Json
+
+#endif // JSON_ARRAY_H

src/util/json/conversion.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_CONVERSION_H
+#define JSON_CONVERSION_H
+
+namespace Json {
+
+namespace Detail {
+
+// Avoid ODR (One Definition Rule) violations
+template<typename T>
+constexpr T staticConst {};
+
+} // namespace Detail
+
+} // namespace Json
+
+#endif // JSON_CONVERSION_H

src/util/json/fromjson.h

@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_FROM_JSON_H
+#define JSON_FROM_JSON_H
+
+#include <algorithm> // transform
+#include <cassert>   // assert
+#include <cstddef>   // nullptr_t
+#include <map>
+#include <string>
+#include <unordered_map>
+#include <utility> // forward
+#include <vector>
+
+#include "util/json/array.h"
+#include "util/json/conversion.h"
+#include "util/json/object.h"
+
+namespace Json {
+
+namespace Detail {
+
+// Required for containers with Json::Value type
+template<typename Json>
+void fromJson(const Json& json, Json& value)
+{
+	value = json;
+}
+
+template<typename Json>
+void fromJson(const Json& json, std::nullptr_t& null)
+{
+	assert(json.type() == Json::Type::Null);
+	null = nullptr;
+}
+
+template<typename Json>
+void fromJson(const Json& json, bool& boolean)
+{
+	assert(json.type() == Json::Type::Bool);
+	boolean = json.asBool();
+}
+
+template<typename Json>
+void fromJson(const Json& json, int& number)
+{
+	assert(json.type() == Json::Type::Number);
+	number = (int)json.asDouble();
+}
+
+template<typename Json>
+void fromJson(const Json& json, double& number)
+{
+	assert(json.type() == Json::Type::Number);
+	number = json.asDouble();
+}
+
+template<typename Json>
+void fromJson(const Json& json, std::string& string)
+{
+	assert(json.type() == Json::Type::String);
+	string = json.asString();
+}
+
+template<typename Json, typename T>
+void fromJson(const Json& json, std::vector<T>& array)
+{
+	assert(json.type() == Json::Type::Array);
+	array.resize(json.size());
+	std::transform(
+		json.asArray().elements().begin(),
+		json.asArray().elements().end(),
+		array.begin(),
+		[](const Json& json) {
+			return json.template get<T>(); // (missing-dependent-template-keyword)
+		});
+}
+
+template<typename Json, typename T>
+void fromJson(const Json& json, std::map<std::string, T>& object)
+{
+	assert(json.type() == Json::Type::Object);
+	object.clear();
+	for (const auto& [name, value] : json.asObject().members()) {
+		object.emplace(name, value.template get<T>());
+	}
+}
+
+template<typename Json, typename T>
+void fromJson(const Json& json, std::unordered_map<std::string, T>& object)
+{
+	assert(json.type() == Json::Type::Object);
+	object.clear();
+	for (const auto& [name, value] : json.asObject().members()) {
+		object.emplace(name, value.template get<T>());
+	}
+}
+
+struct fromJsonFunction {
+	template<typename Json, typename T>
+	auto operator()(const Json& json, T&& value) const
+	{
+		return fromJson(json, std::forward<T>(value));
+	}
+};
+
+} // namespace Detail
+
+// Anonymous namespace prevents multiple definition of the reference
+namespace {
+// Function object
+constexpr const auto& fromJson = Detail::staticConst<Detail::fromJsonFunction>; // NOLINT (misc-definitions-in-headers)
+} // namespace
+
+} // namespace Json
+
+#endif // JSON_FROM_JSON_H
+
+// Customization Points
+// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
+
+// Json::fromJson is a function object, the type of which is
+// Json::Detail::fromJsonFunction. In the Json::Detail namespace are the
+// fromJson free functions. The function call operator of fromJsonFunction makes
+// an unqualified call to fromJson which, since it shares the Detail namespace
+// with the fromJson free functions, will consider those in addition to any
+// overloads that are found by argument-dependent lookup.
+
+// Variable templates are linked externally, therefor every translation unit
+// will see the same address for Detail::staticConst<Detail::fromJsonFunction>.
+// Since Json::fromJson is a reference to the variable template, it too will
+// have the same address in all translation units.

src/util/json/job.cpp

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // count
+#include <sstream>   // istringstream
+#include <string>    // getline
+
+#include "util/json/job.h"
+#include "util/json/lexer.h"
+#include "util/json/parser.h"
+#include "util/json/value.h"
+
+namespace Json {
+
+Job::Job(const std::string& input)
+	: m_input(input)
+{
+	// FIXME: Make this work for all newline types: \n, \r, \r\n
+	m_lineNumbersWidth = std::count(m_input.begin(), m_input.end(), '\n');
+	m_lineNumbersWidth += m_input.back() == '\n' ? 0 : 1;
+	m_lineNumbersWidth = std::to_string(m_lineNumbersWidth).length();
+}
+
+Job::~Job()
+{
+}
+
+// ------------------------------------------
+
+Value Job::fire()
+{
+	Lexer lexer(this);
+	lexer.analyze();
+
+	if (!m_success) {
+		return nullptr;
+	}
+
+	Parser parser(this);
+	Value value = parser.parse();
+
+	if (!m_success) {
+		return nullptr;
+	}
+
+	return value;
+}
+
+void Job::printErrorLine(Token token, const char* message)
+{
+	m_success = false;
+
+	// Error message
+	std::string errorFormat = "\033[;1m" // Bold
+							  "JSON:%zu:%zu: "
+							  "\033[31;1m" // Bold red
+							  "error: "
+							  "\033[0m" // Reset
+							  "%s"
+							  "\n";
+	printf(errorFormat.c_str(),
+	       token.line + 1,
+	       token.column + 1,
+	       message);
+
+	// Get the JSON line that caused the error
+	std::istringstream input(m_input);
+	std::string line;
+	for (size_t i = 0; std::getline(input, line); ++i) {
+		if (i == token.line) {
+			break;
+		}
+	}
+	// Replace tab indentation with spaces
+	size_t oldLineLength = line.length();
+	size_t tabs = line.find_first_not_of('\t');
+	if (tabs > 0 && tabs < line.size()) {
+		line = std::string(tabs * 4, ' ') + line.substr(tabs);
+	}
+	token.column += line.length() - oldLineLength;
+
+	// JSON line
+	std::string lineFormat = " %"
+	                         + std::to_string(m_lineNumbersWidth)
+	                         + "zu | "
+	                           "%s"
+	                           "\033[31;1m" // Bold red
+	                           "%s"
+	                           "\033[0m" // Reset
+	                           "\n";
+	printf(lineFormat.c_str(),
+	       token.line + 1,
+	       line.substr(0, token.column).c_str(),
+	       line.substr(token.column).c_str());
+
+	// Arrow pointer
+	std::string arrowFormat = " %s | "
+							  "\033[31;1m" // Bold red
+							  "%s^%s"
+							  "\033[0m" // Reset
+							  "\n";
+	printf(arrowFormat.c_str(),
+	       std::string(m_lineNumbersWidth, ' ').c_str(),
+	       std::string(token.column, ' ').c_str(),
+	       std::string(line.length() - token.column, '~').c_str());
+}
+
+} // namespace Json

src/util/json/job.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_JOB_H
+#define JSON_JOB_H
+
+#include <cstddef> // size_t
+#include <string>
+#include <vector>
+
+#include "util/json/lexer.h"
+
+namespace Json {
+
+class Value;
+
+class Job {
+public:
+	Job(const std::string& input);
+	virtual ~Job();
+
+	enum class Color {
+		None,
+		Info,
+		Warn,
+		Danger,
+		Success,
+		Comment,
+	};
+
+	Value fire();
+
+	void printErrorLine(Token token, const char* message);
+
+	bool success() const { return m_success; }
+	const std::string& input() const { return m_input; }
+	std::vector<Token>* tokens() { return &m_tokens; }
+
+private:
+	bool m_success { true };
+
+	std::string m_input;
+	size_t m_lineNumbersWidth { 0 };
+
+	std::vector<Token> m_tokens;
+};
+
+} // namespace Json
+
+#endif // JSON_JOB_H

src/util/json/lexer.cpp

@@ -0,0 +1,230 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstddef>
+#include <string>
+
+#include "util/json/job.h"
+#include "util/json/lexer.h"
+
+namespace Json {
+
+Lexer::Lexer(Job* job)
+	: m_job(job)
+	, m_tokens(job->tokens())
+{
+}
+
+Lexer::~Lexer()
+{
+}
+
+// -----------------------------------------
+
+void Lexer::analyze()
+{
+	while (m_index < m_job->input().length()) {
+		switch (peek()) {
+		case '{':
+			m_tokens->push_back({ Token::Type::BraceOpen, m_line, m_column, "{" });
+			break;
+		case '}':
+			m_tokens->push_back({ Token::Type::BraceClose, m_line, m_column, "}" });
+			break;
+		case '[':
+			m_tokens->push_back({ Token::Type::BracketOpen, m_line, m_column, "[" });
+			break;
+		case ']':
+			m_tokens->push_back({ Token::Type::BracketClose, m_line, m_column, "]" });
+			break;
+		case ':':
+			m_tokens->push_back({ Token::Type::Colon, m_line, m_column, ":" });
+			break;
+		case ',':
+			m_tokens->push_back({ Token::Type::Comma, m_line, m_column, "," });
+			break;
+		case '"':
+			if (!getString()) {
+				return;
+			}
+			break;
+		case '-':
+		case '0':
+		case '1':
+		case '2':
+		case '3':
+		case '4':
+		case '5':
+		case '6':
+		case '7':
+		case '8':
+		case '9':
+			if (!getNumber()) {
+				return;
+			}
+			break;
+		case 'a':
+		case 'b':
+		case 'c':
+		case 'd':
+		case 'e':
+		case 'f':
+		case 'g':
+		case 'h':
+		case 'i':
+		case 'j':
+		case 'k':
+		case 'l':
+		case 'm':
+		case 'n':
+		case 'o':
+		case 'p':
+		case 'q':
+		case 'r':
+		case 's':
+		case 't':
+		case 'u':
+		case 'v':
+		case 'w':
+		case 'x':
+		case 'y':
+		case 'z':
+			if (!getLiteral()) {
+				return;
+			}
+			break;
+		case ' ':
+		case '\t':
+			break;
+		case '\r':
+			if (peekNext() == '\n') { // CRLF \r\n
+				break;
+			}
+			m_column = -1;
+			m_line++;
+			break;
+		case '\n':
+			m_column = -1;
+			m_line++;
+			break;
+		default:
+			// Error!
+			m_tokens->push_back({ Token::Type::None, m_line, m_column, std::string(1, peek()) });
+			m_job->printErrorLine(m_tokens->back(),
+			                      (std::string() + "unexpected character '" + peek() + "'").c_str());
+			return;
+			break;
+		}
+
+		increment();
+	}
+}
+
+// -----------------------------------------
+
+char Lexer::peek()
+{
+	return m_job->input()[m_index];
+}
+
+char Lexer::peekNext()
+{
+	return m_job->input()[m_index + 1];
+}
+
+void Lexer::increment()
+{
+	m_index++;
+	m_column++;
+}
+
+void Lexer::decrement()
+{
+	m_index--;
+	m_column--;
+}
+
+char Lexer::consume()
+{
+	char character = peek();
+	increment();
+	return character;
+}
+
+bool Lexer::getString()
+{
+	size_t column = m_column;
+	std::string symbol = "";
+	std::string breakOnCharacter = std::string() + '"' + '\r' + '\n' + '\0';
+
+	bool escape = false;
+	char character = consume();
+	for (;;) {
+		character = peek();
+
+		if (!escape && character == '\\') {
+			symbol += '\\';
+			increment();
+			escape = true;
+			continue;
+		}
+
+		if (!escape && breakOnCharacter.find(character) != std::string::npos) {
+			break;
+		}
+
+		symbol += character;
+		increment();
+
+		if (escape) {
+			escape = false;
+		}
+	}
+
+	m_tokens->push_back({ Token::Type::String, m_line, column, symbol });
+
+	if (character != '"') {
+		m_job->printErrorLine(m_job->tokens()->back(), "strings should be wrapped in double quotes");
+		return false;
+	}
+
+	return true;
+}
+
+bool Lexer::getNumberOrLiteral(Token::Type type)
+{
+	size_t column = m_column;
+	std::string symbol = "";
+	std::string breakOnCharacter = std::string("{}[]:,") + '"' + ' ' + '\t' + '\r' + '\n' + '\0';
+
+	for (char character;;) {
+		character = peek();
+
+		if (breakOnCharacter.find(character) != std::string::npos) {
+			break;
+		}
+
+		symbol += character;
+		increment();
+	}
+	decrement();
+
+	m_tokens->push_back({ type, m_line, column, symbol });
+
+	return true;
+}
+
+bool Lexer::getNumber()
+{
+	return getNumberOrLiteral(Token::Type::Number);
+}
+
+bool Lexer::getLiteral()
+{
+	return getNumberOrLiteral(Token::Type::Literal);
+}
+
+} // namespace Json

src/util/json/lexer.h

@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_LEXER_H
+#define JSON_LEXER_H
+
+// The JavaScript Object Notation (JSON) Data Interchange Format
+// https://www.rfc-editor.org/rfc/pdfrfc/rfc8259.txt.pdf
+
+#include <cstddef> // size_t
+#include <memory>  // shared_ptr
+#include <string>
+#include <vector>
+
+namespace Json {
+
+class Job;
+
+struct Token {
+	enum class Type {
+		None,
+		BraceOpen,    // {
+		BraceClose,   // }
+		BracketOpen,  // [
+		BracketClose, // ]
+		Colon,        // :
+		Comma,        // ,
+		String,       // "foobar"
+		Number,       // 123.456
+		Literal,      // false/null/true (case sensitive)
+	};
+
+	Type type { Type::None };
+	size_t line { 0 };
+	size_t column { 0 };
+	std::string symbol;
+};
+
+// Lexical analyzer
+class Lexer {
+public:
+	Lexer(Job* job);
+	virtual ~Lexer();
+
+	void analyze();
+
+private:
+	char peek();
+	char peekNext();
+
+	void increment();
+	void decrement();
+	char consume();
+
+	bool getString();
+	bool getNumberOrLiteral(Token::Type type);
+	bool getNumber();
+	bool getLiteral();
+
+	Job* m_job { nullptr };
+
+	size_t m_index { 0 };
+	size_t m_column { 0 };
+	size_t m_line { 0 };
+
+	std::vector<Token>* m_tokens { nullptr };
+};
+
+} // namespace Json
+
+#endif // JSON_LEXER_H

src/util/json/object.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "util/json/object.h"
+#include "util/json/value.h"
+
+namespace Json {
+
+void Object::emplace(const std::string& name, Value value)
+{
+	m_members.emplace(name, std::move(value));
+}
+
+Value& Object::operator[](const std::string& name)
+{
+	if (m_members.find(name) == m_members.end()) {
+		emplace(name, {});
+	}
+
+	return m_members.at(name);
+}
+
+} // namespace Json

src/util/json/object.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_OBJECT_H
+#define JSON_OBJECT_H
+
+#include <map>
+#include <string>
+#include <utility> // move
+
+#include "util/json/parser.h"
+
+namespace Json {
+
+class Value;
+
+class Object {
+public:
+	Object() {}
+	virtual ~Object() {}
+
+	Object(const Object& other)
+		: m_members(other.m_members)
+	{
+	}
+
+	void emplace(const std::string& name, Value value);
+
+	Value& operator[](const std::string& name);
+
+	Value& at(const std::string& name) { return m_members.at(name); }
+	const Value& at(const std::string& name) const { return m_members.at(name); }
+
+	size_t size() const { return m_members.size(); }
+	const std::map<std::string, Value>& members() const { return m_members; }
+
+private:
+	std::map<std::string, Value> m_members;
+};
+
+} // namespace Json
+
+#endif // JSON_OBJECT_H

src/util/json/parser.cpp

@@ -0,0 +1,493 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // count
+#include <cstddef>   // size_t
+#include <cstdint>   // uint8_t
+#include <cstdio>    // printf
+#include <map>
+#include <string> // stod
+
+#include "util/json/array.h"
+#include "util/json/job.h"
+#include "util/json/lexer.h"
+#include "util/json/object.h"
+#include "util/json/parser.h"
+#include "util/json/value.h"
+
+namespace Json {
+
+Parser::Parser(Job* job)
+	: m_job(job)
+	, m_tokens(m_job->tokens())
+{
+}
+
+Parser::~Parser()
+{
+}
+
+// -----------------------------------------
+
+Value Parser::parse()
+{
+	Value result;
+
+	if (m_tokens->size() == 0) {
+		m_job->printErrorLine({}, "expecting token, not 'EOF'");
+		return result;
+	}
+
+	Token token = peek();
+	switch (token.type) {
+	case Token::Type::Literal:
+		result = getLiteral();
+		break;
+	case Token::Type::Number:
+		result = getNumber();
+		break;
+	case Token::Type::String:
+		result = getString();
+		break;
+	case Token::Type::BracketOpen:
+		result = getArray();
+		break;
+	case Token::Type::BraceOpen:
+		result = getObject();
+		break;
+	case Token::Type::BracketClose:
+		m_job->printErrorLine(token, "expecting value, not ']'");
+		m_index++;
+		break;
+	case Token::Type::BraceClose:
+		m_job->printErrorLine(token, "expecting string, not '}'");
+		m_index++;
+		break;
+	default:
+		m_job->printErrorLine(token, "multiple root elements");
+		m_index++;
+		break;
+	}
+
+	if (!reachedEnd()) {
+		m_job->printErrorLine(peek(), "multiple root elements");
+	}
+
+	return result;
+}
+
+// -----------------------------------------
+
+bool Parser::reachedEnd()
+{
+	return m_index >= m_tokens->size();
+}
+
+bool Parser::seekForward(Token::Type type)
+{
+	for (; !reachedEnd(); ++m_index) {
+		if (peek().type == type) {
+			m_index++;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+Token Parser::peek()
+{
+	return m_tokens->at(m_index);
+}
+
+Token Parser::consume()
+{
+	Token token = peek();
+	m_index++;
+	return token;
+}
+
+Value Parser::getLiteral()
+{
+	Token token = consume();
+
+	if (token.symbol == "null") {
+		return nullptr;
+	}
+	else if (token.symbol == "true") {
+		return true;
+	}
+	else if (token.symbol == "false") {
+		return false;
+	}
+
+	m_job->printErrorLine(token, "invalid literal");
+	return nullptr;
+}
+
+Value Parser::getNumber()
+{
+	Token token = consume();
+
+	auto reportError = [this](Token token, const std::string& message) -> void {
+		m_job->printErrorLine(token, message.c_str());
+	};
+
+	// Validation
+	// number = [ minus ] int [ frac ] [ exp ]
+
+	size_t minusPrefix = token.symbol[0] == '-' ? 1 : 0;
+
+	// Leading 0s
+	if (token.symbol[minusPrefix] == '0'
+	    && token.symbol[minusPrefix + 1] > '0' && token.symbol[minusPrefix + 1] < '9') {
+		reportError(token, "invalid leading zero");
+		return nullptr;
+	}
+
+	enum class State {
+		Int,
+		Fraction,
+		Exponent
+	};
+
+	State state = State::Int;
+	std::string validCharacters = "0123456789-";
+
+	size_t fractionPosition = 0;
+	size_t exponentPosition = 0;
+	size_t length = token.symbol.length();
+	for (size_t i = 0; i < length; ++i) {
+		char character = token.symbol[i];
+
+		// Int -> Fraction
+		if (character == '.' && state == State::Int) {
+			state = State::Fraction;
+			validCharacters = "0123456789";
+			fractionPosition = i;
+			continue;
+		}
+		// Int/Fraction -> Exponent
+		else if ((character == 'e' || character == 'E') && state != State::Exponent) {
+			state = State::Exponent;
+			validCharacters = "0123456789+-";
+			exponentPosition = i;
+			continue;
+		}
+
+		if (state == State::Int) {
+			if (character == '-') {
+				if (i == length - 1) {
+					reportError(token, "expected number after minus");
+					return nullptr;
+				}
+				if (i != 0) {
+					reportError(token, "invalid minus");
+					return nullptr;
+				}
+			}
+		}
+		else if (state == State::Fraction) {
+		}
+		else if (state == State::Exponent) {
+			if (character == '-' || character == '+') {
+				if (i == length - 1) {
+					reportError(token, "expected number after plus/minus");
+					return nullptr;
+				}
+				if (i > exponentPosition + 1) {
+					reportError(token, "invalid plus/minus");
+					return nullptr;
+				}
+			}
+		}
+
+		if (validCharacters.find(character) == std::string::npos) {
+			reportError(token, std::string() + "invalid number, unexpected '" + character + '\'');
+			return nullptr;
+		}
+	}
+
+	if (fractionPosition != 0 || exponentPosition != 0) {
+		if (fractionPosition == exponentPosition - 1) {
+			reportError(token, "invalid exponent sign, expected number");
+			return nullptr;
+		}
+
+		if (fractionPosition == length - 1 || exponentPosition == length - 1) {
+			reportError(token, "invalid number");
+			return nullptr;
+		}
+	}
+
+	return std::stod(token.symbol);
+}
+
+Value Parser::getString()
+{
+	Token token = consume();
+
+	auto reportError = [this](Token token, const std::string& message) -> void {
+		m_job->printErrorLine(token, message.c_str());
+	};
+
+	// FIXME: support \u Unicode character escape sequence
+	auto getPrintableString = [](char character) -> std::string {
+		if (character == '"' || character == '\\' || character == '/'
+		    || (character >= 0 && character <= 31)) {
+			switch (character) {
+			case '"':
+				return "\\\"";
+				break;
+			case '\\':
+				return "\\\\";
+				break;
+			case '/':
+				return "/";
+				break;
+			case '\b':
+				return "\\b";
+				break;
+			case '\f':
+				return "\\f";
+				break;
+			case '\n':
+				return "\\n";
+				break;
+			case '\r':
+				return "\\r";
+				break;
+			case '\t':
+				return "\\t";
+				break;
+			default:
+				char buffer[7];
+				sprintf(buffer, "\\u%0.4X", character);
+				return std::string(buffer);
+				break;
+			}
+		}
+
+		return std::string() + character;
+	};
+
+	std::string string;
+
+	bool escape = false;
+	for (char character : token.symbol) {
+		if (!escape) {
+			if (character == '\\') {
+				escape = true;
+				continue;
+			}
+
+			if (character == '"' || (character >= 0 && character <= 31)) {
+				reportError(token, "invalid string, unescaped character found");
+				return nullptr;
+			}
+		}
+
+		string += getPrintableString(character);
+
+		if (escape) {
+			escape = false;
+		}
+	}
+
+	return string;
+}
+
+Value Parser::getArray()
+{
+	m_index++;
+
+	auto reportError = [this](Token token, const std::string& message) -> void {
+		m_job->printErrorLine(token, message.c_str());
+
+		// After an error, try to find the closing bracket
+		seekForward(Token::Type::BracketClose);
+	};
+
+	Value array = Value::Type::Array;
+	Token token;
+	for (;;) {
+		// EOF
+		if (reachedEnd()) {
+			reportError(m_tokens->at(m_index - 1), "expecting closing ']' at end");
+			break;
+		}
+
+		token = peek();
+		if (token.type == Token::Type::Literal) {
+			array.emplace_back(getLiteral());
+		}
+		else if (token.type == Token::Type::Number) {
+			array.emplace_back(getNumber());
+		}
+		else if (token.type == Token::Type::String) {
+			array.emplace_back(getString());
+		}
+		else if (token.type == Token::Type::BracketOpen) {
+			array.emplace_back(getArray());
+		}
+		else if (token.type == Token::Type::BraceOpen) {
+			array.emplace_back(getObject());
+		}
+		else if (token.type == Token::Type::BracketClose) {
+			// Trailing comma
+			if (array.m_value.array->size() > 0) {
+				reportError(m_tokens->at(m_index - 1), "invalid comma, expecting ']'");
+				break;
+			}
+		}
+		else {
+			reportError(token, "expecting value or ']', not '" + token.symbol + "'");
+			break;
+		}
+
+		// EOF
+		if (reachedEnd()) {
+			reportError(token, "expecting closing ']' at end");
+			break;
+		}
+
+		// Find , or ]
+		token = consume();
+		if (token.type == Token::Type::Comma) {
+			continue;
+		}
+		else if (token.type == Token::Type::BracketClose) {
+			break;
+		}
+		else {
+			reportError(m_tokens->at(m_index - 1), "expecting comma or ']', not '" + token.symbol + "'");
+			break;
+		}
+	}
+
+	return array;
+}
+
+Value Parser::getObject()
+{
+	m_index++;
+
+	auto reportError = [this](Token token, const std::string& message) -> void {
+		m_job->printErrorLine(token, message.c_str());
+
+		// After an error, try to find the closing brace
+		seekForward(Token::Type::BraceClose);
+	};
+
+	Value object = Value::Type::Object;
+	Token token;
+	std::string name;
+	std::map<std::string, uint8_t> unique;
+	for (;;) {
+		// EOF
+		if (reachedEnd()) {
+			reportError(m_tokens->at(m_index - 1), "expecting closing '}' at end");
+			break;
+		}
+
+		token = consume();
+		if (token.type == Token::Type::BraceClose) {
+			// Trailing comma
+			if (object.m_value.object->size() > 0) {
+				reportError(m_tokens->at(m_index - 1), "invalid comma, expecting '}'");
+			}
+			// Empty object
+			break;
+		}
+		if (token.type != Token::Type::String) {
+			reportError(token, "expecting string or '}', not '" + token.symbol + "'");
+			break;
+		}
+
+		// Find member name
+		m_index--;
+		Value tmpName = getString();
+		if (tmpName.m_type != Value::Type::String) {
+			seekForward(Token::Type::BraceClose);
+			break;
+		}
+
+		// Check if name exists in hashmap
+		name = *tmpName.m_value.string;
+		if (unique.find(name) != unique.end()) {
+			reportError(token, "duplicate name '" + token.symbol + "', names should be unique");
+			break;
+		}
+		// Add name to hashmap
+		unique.insert({ name, 0 });
+
+		// EOF
+		if (reachedEnd()) {
+			reportError(token, "expecting colon, not 'EOF'");
+			reportError(token, "expecting closing '}' at end");
+			break;
+		}
+
+		// Find :
+		token = consume();
+		if (token.type != Token::Type::Colon) {
+			reportError(token, "expecting colon, not '" + token.symbol + "'");
+			break;
+		}
+
+		// EOF
+		if (reachedEnd()) {
+			reportError(token, "expecting value, not 'EOF'");
+			reportError(token, "expecting closing '}' at end");
+			break;
+		}
+
+		// Add member (name:value pair) to object
+		token = peek();
+		if (token.type == Token::Type::Literal) {
+			object[name] = getLiteral();
+		}
+		else if (token.type == Token::Type::Number) {
+			object[name] = getNumber();
+		}
+		else if (token.type == Token::Type::String) {
+			object[name] = getString();
+		}
+		else if (token.type == Token::Type::BracketOpen) {
+			object[name] = getArray();
+		}
+		else if (token.type == Token::Type::BraceOpen) {
+			object[name] = getObject();
+		}
+		else {
+			reportError(token, "expecting value, not '" + token.symbol + "'");
+			break;
+		}
+
+		// EOF
+		if (reachedEnd()) {
+			reportError(token, "expecting closing '}' at end");
+			break;
+		}
+
+		// Find , or }
+		token = consume();
+		if (token.type == Token::Type::Comma) {
+			continue;
+		}
+		else if (token.type == Token::Type::BraceClose) {
+			break;
+		}
+		else {
+			reportError(token, "expecting comma or '}', not '" + token.symbol + "'");
+			break;
+		}
+	}
+
+	return object;
+}
+
+} // namespace Json

src/util/json/parser.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_PARSER_H
+#define JSON_PARSER_H
+
+#include <cstddef> // size_t
+#include <vector>
+
+#include "util/json/lexer.h"
+
+namespace Json {
+
+class Job;
+class Value;
+
+class Parser {
+public:
+	Parser(Job* job);
+	virtual ~Parser();
+
+	Value parse();
+
+private:
+	bool reachedEnd();
+	bool seekForward(Token::Type type);
+
+	Token peek();
+	Token consume();
+
+	Value getLiteral();
+	Value getNumber();
+	Value getString();
+	Value getArray();
+	Value getObject();
+
+	Job* m_job { nullptr };
+
+	size_t m_index { 0 };
+
+	std::vector<Token>* m_tokens { nullptr };
+};
+
+} // namespace Json
+
+#endif // JSON_PARSER_H

src/util/json/serializer.cpp

@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdint>  // uint32_t
+#include <iterator> // prev
+#include <sstream>  // ostringstream
+#include <string>
+
+#include "util/json/array.h"
+#include "util/json/lexer.h"
+#include "util/json/object.h"
+#include "util/json/serializer.h"
+
+namespace Json {
+
+Serializer::Serializer(const Value& value, const uint32_t indent, const char indentCharacter)
+	: m_value(value)
+	, m_indent(indent)
+	, m_indentCharacter(indentCharacter)
+{
+}
+
+Serializer::~Serializer()
+{
+}
+
+// ------------------------------------------
+
+std::string Serializer::dump()
+{
+	return dumpHelper(m_value);
+}
+
+// ------------------------------------------
+
+std::string Serializer::dumpHelper(const Value& value, const uint32_t indentLevel)
+{
+	switch (value.m_type) {
+	case Value::Type::Null:
+		return "null";
+		break;
+	case Value::Type::Bool:
+		return value.m_value.boolean ? "true" : "false";
+		break;
+	case Value::Type::Number: {
+		std::ostringstream os;
+		os << value.m_value.number;
+		return os.str();
+		break;
+	}
+	case Value::Type::String:
+		return "\"" + *value.m_value.string + "\"";
+		break;
+	case Value::Type::Array:
+		return dumpArray(value, indentLevel);
+		break;
+	case Value::Type::Object:
+		return dumpObject(value, indentLevel);
+		break;
+	default:
+		break;
+	}
+
+	return "";
+}
+
+std::string Serializer::dumpArray(const Value& value, const uint32_t indentLevel)
+{
+	std::string result;
+
+	// Append [
+	result += "[";
+	if (m_indent > 0) {
+		result += '\n';
+	}
+
+	auto values = value.m_value.array->elements();
+	for (auto it = values.begin(); it != values.end(); ++it) {
+		result += std::string(m_indent * (indentLevel + 1), m_indentCharacter);
+		result += dumpHelper(*it, indentLevel + 1);
+
+		// Add comma, except after the last element
+		if (it != std::prev(values.end(), 1)) {
+			result += ",";
+		}
+		if (m_indent > 0) {
+			result += '\n';
+		}
+	}
+
+	// Append indentation
+	result += std::string(m_indent * indentLevel, m_indentCharacter);
+
+	// Append ]
+	result += "]";
+
+	return result;
+}
+
+std::string Serializer::dumpObject(const Value& value, const uint32_t indentLevel)
+{
+	std::string result;
+
+	// Append {
+	result += "{";
+	if (m_indent > 0) {
+		result += '\n';
+	}
+
+	auto members = value.m_value.object->members();
+	for (auto it = members.begin(); it != members.end(); ++it) {
+		result += std::string(m_indent * (indentLevel + 1), m_indentCharacter);
+		result += "\"" + it->first + "\":";
+		if (m_indent > 0) {
+			result += ' ';
+		}
+		result += dumpHelper(it->second, indentLevel + 1);
+
+		// Add comma, except after the last element
+		if (it != std::prev(members.end(), 1)) {
+			result += ",";
+		}
+		if (m_indent > 0) {
+			result += '\n';
+		}
+	}
+
+	// Append indentation
+	result += std::string(m_indent * indentLevel, m_indentCharacter);
+
+	// Append }
+	result += "}";
+
+	return result;
+}
+
+} // namespace Json

src/util/json/serializer.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_SERIALIZER_H
+#define JSON_SERIALIZER_H
+
+#include <cstdint> // uint32_t
+#include <string>
+
+#include "util/json/value.h"
+
+namespace Json {
+
+class Serializer {
+public:
+	Serializer(const Value& value, const uint32_t indent = 0, const char indentCharacter = ' ');
+	virtual ~Serializer();
+
+	std::string dump();
+
+private:
+	std::string dumpHelper(const Value& value, const uint32_t indentLevel = 0);
+	std::string dumpArray(const Value& value, const uint32_t indentLevel = 0);
+	std::string dumpObject(const Value& value, const uint32_t indentLevel = 0);
+
+	Value m_value;
+
+	uint32_t m_indent { 0 };
+	char m_indentCharacter { ' ' };
+};
+
+} // namespace Json
+
+#endif // JSON_SERIALIZER_H

src/util/json/tojson.h

@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_TO_JSON_H
+#define JSON_TO_JSON_H
+
+#include <cassert> // assert
+#include <cstddef> // nullptr_t
+#include <map>
+#include <string>
+#include <unordered_map>
+#include <utility> // forward
+
+#include "util/json/array.h"
+#include "util/json/conversion.h"
+#include "util/json/object.h"
+
+namespace Json {
+
+namespace Detail {
+
+struct jsonConstructor {
+	template<typename Json>
+	static void construct(Json& json, bool boolean)
+	{
+		json.clear();
+		json.m_type = Json::Type::Bool;
+		json.m_value.boolean = boolean;
+	}
+
+	template<typename Json>
+	static void construct(Json& json, int number)
+	{
+		json.clear();
+		json.m_type = Json::Type::Number;
+		json.m_value.number = (double)number;
+	}
+
+	template<typename Json>
+	static void construct(Json& json, double number)
+	{
+		json.clear();
+		json.m_type = Json::Type::Number;
+		json.m_value.number = number;
+	}
+
+	template<typename Json>
+	static void construct(Json& json, const char* string)
+	{
+		json.clear();
+		json.m_type = Json::Type::String;
+		json.m_value.string = new std::string(string);
+	}
+
+	template<typename Json>
+	static void construct(Json& json, const std::string& string)
+	{
+		json.clear();
+		json.m_type = Json::Type::String;
+		json.m_value.string = new std::string(string);
+	}
+
+	template<typename Json>
+	static void construct(Json& json, const Array& array)
+	{
+		json.clear();
+		json.m_type = Json::Type::Array;
+		json.m_value.array = new Array(array);
+	}
+
+	template<typename Json, typename T>
+	static void construct(Json& json, const std::vector<T>& array)
+	{
+		json.clear();
+		json.m_type = Json::Type::Array;
+		json.m_value.array = new Array;
+		json.m_value.array->reserve(array.size());
+		for (const T& value : array) {
+			json.m_value.array->emplace_back(value);
+		}
+	}
+
+	template<typename Json>
+	static void construct(Json& json, const Object& object)
+	{
+		json.clear();
+		json.m_type = Json::Type::Object;
+		json.m_value.object = new Object(object);
+	}
+
+	template<typename Json, typename T>
+	static void construct(Json& json, const std::map<std::string, T>& object)
+	{
+		json.clear();
+		json.m_type = Json::Type::Object;
+		json.m_value.object = new Object;
+		for (const auto& [name, value] : object) {
+			json.m_value.object->emplace(name, value);
+		}
+	}
+
+	template<typename Json, typename T>
+	static void construct(Json& json, const std::unordered_map<std::string, T>& object)
+	{
+		json.clear();
+		json.m_type = Json::Type::Object;
+		json.m_value.object = new Object;
+		for (const auto& [name, value] : object) {
+			json.m_value.object->emplace(name, value);
+		}
+	}
+};
+
+template<typename Json, typename T>
+void toJson(Json& json, const T& value)
+{
+	jsonConstructor::construct(json, value);
+}
+
+struct toJsonFunction {
+	template<typename Json, typename T>
+	auto operator()(Json& json, T&& value) const
+	{
+		return toJson(json, std::forward<T>(value));
+	}
+};
+
+} // namespace Detail
+
+// Anonymous namespace prevents multiple definition of the reference
+namespace {
+// Function object
+constexpr const auto& toJson = Detail::staticConst<Detail::toJsonFunction>; // NOLINT (misc-definitions-in-headers)
+} // namespace
+
+} // namespace Json
+
+#endif // JSON_TO_JSON_H
+
+// Customization Points
+// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
+
+// Json::fromJson is a function object, the type of which is
+// Json::Detail::fromJsonFunction. In the Json::Detail namespace are the
+// fromJson free functions. The function call operator of fromJsonFunction makes
+// an unqualified call to fromJson which, since it shares the Detail namespace
+// with the fromJson free functions, will consider those in addition to any
+// overloads that are found by argument-dependent lookup.
+
+// Variable templates are linked externally, therefor every translation unit
+// will see the same address for Detail::staticConst<Detail::fromJsonFunction>.
+// Since Json::fromJson is a reference to the variable template, it too will
+// have the same address in all translation units.

src/util/json/value.cpp

@@ -0,0 +1,296 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // all_of
+#include <cassert>   // assert
+#include <cstdint>   // uint32_t
+#include <iostream>  // istream, ostream
+#include <string>
+#include <utility> // move
+
+#include "util/json/array.h"
+#include "util/json/job.h"
+#include "util/json/object.h"
+#include "util/json/serializer.h"
+#include "util/json/value.h"
+
+namespace Json {
+
+Value::Value(std::nullptr_t)
+	: Value(Type::Null)
+{
+}
+
+Value::Value(Type type)
+	: m_type(type)
+{
+	create();
+}
+
+Value::Value(const std::initializer_list<Value>& values)
+{
+	bool isObject = std::all_of(values.begin(), values.end(), [](const Value& value) {
+		return value.type() == Type::Array
+		       && value.size() == 2
+		       && value[0].m_type == Type::String;
+	});
+
+	if (!isObject) {
+		m_type = Type::Array;
+		m_value.array = new Array(values);
+	}
+	else {
+		m_type = Type::Object;
+		m_value.object = new Object;
+
+		for (auto& value : values) {
+			m_value.object->emplace(std::move(*value[0].m_value.string),
+			                          std::move(value[1]));
+		}
+	}
+}
+
+// Copy constructor
+Value::Value(const Value& other)
+{
+	copyFrom(other);
+}
+
+// Assignment operator
+Value& Value::operator=(const Value& other)
+{
+	if (this != &other) {
+		clear();
+		copyFrom(other);
+	}
+
+	return *this;
+}
+
+// ------------------------------------------
+
+Value Value::parse(const std::string& input)
+{
+	Job job(input);
+	Value value = job.fire();
+
+	return value;
+}
+
+std::string Value::dump(const uint32_t indent, const char indentCharacter) const
+{
+	Serializer serializer(*this, indent, indentCharacter);
+	return serializer.dump();
+}
+
+void Value::emplace_back(Value value)
+{
+	// Implicitly convert null to an array
+	if (m_type == Type::Null) {
+		m_type = Type::Array;
+		m_value.array = new Array;
+	}
+
+	assert(m_type == Type::Array);
+	m_value.array->emplace_back(value);
+}
+
+void Value::emplace(const std::string& key, Value value)
+{
+	// Implicitly convert null to an object
+	if (m_type == Type::Null) {
+		m_type = Type::Object;
+		m_value.object = new Object;
+	}
+
+	assert(m_type == Type::Object);
+	m_value.object->emplace(key, value);
+}
+
+bool Value::exists(size_t index) const
+{
+	return index < size();
+}
+
+bool Value::exists(const std::string& key) const
+{
+	assert(m_type == Type::Object);
+	return m_value.object->members().find(key) != m_value.object->members().end();
+}
+
+// ------------------------------------------
+
+Value& Value::operator[](size_t index)
+{
+	// Implicitly convert null to an array
+	if (m_type == Type::Null) {
+		m_type = Type::Array;
+		m_value.array = new Array;
+	}
+
+	assert(m_type == Type::Array);
+	return (*m_value.array)[index];
+}
+
+Value& Value::operator[](const std::string& key)
+{
+	// Implicitly convert null to an object
+	if (m_type == Type::Null) {
+		m_type = Type::Object;
+		m_value.object = new Object;
+	}
+
+	assert(m_type == Type::Object);
+	return (*m_value.object)[key];
+}
+
+const Value& Value::operator[](size_t index) const
+{
+	assert(m_type == Type::Array);
+	return (*m_value.array)[index];
+}
+
+const Value& Value::operator[](const std::string& key) const
+{
+	assert(m_type == Type::Object);
+	return (*m_value.object)[key];
+}
+
+Value& Value::at(size_t index)
+{
+	assert(m_type == Type::Array);
+	return m_value.array->at(index);
+}
+
+Value& Value::at(const std::string& key)
+{
+	assert(m_type == Type::Object);
+	return m_value.object->at(key);
+}
+
+const Value& Value::at(size_t index) const
+{
+	assert(m_type == Type::Array);
+	return m_value.array->at(index);
+}
+
+const Value& Value::at(const std::string& key) const
+{
+	assert(m_type == Type::Object);
+	return m_value.object->at(key);
+}
+
+// ------------------------------------------
+
+size_t Value::size() const
+{
+	switch (m_type) {
+	case Type::Null:
+		return 0;
+	case Type::Bool:
+	case Type::Number:
+	case Type::String:
+		return 1;
+	case Type::Array:
+		return m_value.array->size();
+	case Type::Object:
+		return m_value.object->size();
+	default:
+		return 1;
+	}
+}
+
+// ------------------------------------------
+
+void Value::create()
+{
+	switch (m_type) {
+	case Type::Bool:
+		m_value.boolean = false;
+		break;
+	case Type::Number:
+		m_value.number = 0.0;
+		break;
+	case Type::String:
+		m_value.string = new std::string;
+		break;
+	case Type::Array:
+		m_value.array = new Array;
+		break;
+	case Type::Object:
+		m_value.object = new Object;
+		break;
+	default:
+		break;
+	}
+}
+
+void Value::clear()
+{
+	switch (m_type) {
+	case Type::String:
+		delete m_value.string;
+		break;
+	case Type::Array:
+		delete m_value.array;
+		break;
+	case Type::Object:
+		delete m_value.object;
+		break;
+	default:
+		break;
+	}
+}
+
+void Value::copyFrom(const Value& other)
+{
+	m_type = other.m_type;
+
+	switch (m_type) {
+	case Type::Bool:
+		m_value.boolean = other.m_value.boolean;
+		break;
+	case Type::Number:
+		m_value.number = other.m_value.number;
+		break;
+	case Type::String:
+		m_value.string = new std::string(*other.m_value.string);
+		break;
+	case Type::Array:
+		m_value.array = new Array(*other.m_value.array);
+		break;
+	case Type::Object:
+		m_value.object = new Object(*other.m_value.object);
+		break;
+	default:
+		break;
+	}
+}
+
+// ------------------------------------------
+
+std::istream& operator>>(std::istream& input, Value& value)
+{
+	std::string inputString;
+
+	char buffer[4096];
+	while (input.read(buffer, sizeof(buffer))) {
+		inputString.append(buffer, sizeof(buffer));
+	}
+	inputString.append(buffer, input.gcount());
+
+	Job job(inputString);
+	value = job.fire();
+
+	return input;
+}
+
+std::ostream& operator<<(std::ostream& output, const Value& value)
+{
+	return output << value.dump(4);
+}
+
+} // namespace Json

src/util/json/value.h

@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_VALUE_H
+#define JSON_VALUE_H
+
+#include <cstddef> // nullptr_t
+#include <cstdint> // uint32_t
+#include <initializer_list>
+#include <iostream> // istream, ostream
+#include <string>
+#include <utility> // forward
+
+#include "util/json/fromjson.h"
+#include "util/json/tojson.h"
+
+namespace Json {
+
+class Array;
+class Object;
+
+class Value {
+private:
+	friend Detail::jsonConstructor;
+	friend class Parser;
+	friend class Serializer;
+
+public:
+	enum class Type {
+		Null,   // null       (case sensitive!)
+		Bool,   // true/false (case sensitive!)
+		Number, // 123
+		String, // ""
+		Array,  // []
+		Object, // {}
+	};
+
+	// Constructors
+	Value(std::nullptr_t = nullptr);
+	Value(Type type);
+	Value(const std::initializer_list<Value>& values);
+	template<typename T>
+	Value(T value)
+	{
+		toJson(*this, std::forward<T>(value));
+	}
+
+	// Destructor
+	virtual ~Value() { clear(); }
+
+	// Copy constructor
+	Value(const Value& other);
+
+	// Assignment operator
+	Value& operator=(const Value& other);
+
+	// --------------------------------------
+
+	static Value parse(const std::string& input);
+	std::string dump(const uint32_t indent = 0, const char indentCharacter = ' ') const;
+
+	void emplace_back(Value value);
+	void emplace(const std::string& key, Value value);
+
+	bool exists(size_t index) const;
+	bool exists(const std::string& key) const;
+
+	// --------------------------------------
+
+	// Array index operator
+	Value& operator[](size_t index);
+	Value& operator[](const std::string& key);
+	const Value& operator[](size_t index) const;
+	const Value& operator[](const std::string& key) const;
+
+	Value& at(size_t index);
+	Value& at(const std::string& key);
+	const Value& at(size_t index) const;
+	const Value& at(const std::string& key) const;
+
+	// --------------------------------------
+
+	template<typename T>
+	T get() const
+	{
+		T type;
+		fromJson(*this, type);
+		return type;
+	}
+
+	template<typename T>
+	void getTo(T& type) const
+	{
+		fromJson(*this, type);
+	}
+
+	// --------------------------------------
+
+	Type type() const { return m_type; }
+	size_t size() const;
+
+	bool asBool() const { return m_value.boolean; }
+	double asDouble() const { return m_value.number; }
+	const std::string& asString() const { return *m_value.string; }
+	const Array& asArray() const { return *m_value.array; }
+	const Object& asObject() const { return *m_value.object; }
+
+private:
+	void create();
+	void clear();
+	void copyFrom(const Value& other);
+
+	Type m_type { Type::Null };
+
+	union {
+		bool boolean;
+		double number;
+		std::string* string;
+		Array* array;
+		Object* object;
+	} m_value {};
+};
+
+std::istream& operator>>(std::istream& input, Value& value);
+std::ostream& operator<<(std::ostream& output, const Value& value);
+
+} // namespace Json
+
+#endif // JSON_VALUE_H

test/unit/testutiljson.cpp

@@ -0,0 +1,570 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstddef>    // nullptr_t
+#include <cstdint>    // uint32_t
+#include <functional> // function
+#include <map>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "macro.h"
+#include "testcase.h"
+#include "testsuite.h"
+#include "util/json/array.h"
+#include "util/json/job.h"
+#include "util/json/lexer.h"
+#include "util/json/parser.h"
+#include "util/json/serializer.h"
+#include "util/json/value.h"
+
+#define DONT_PRINT_PARSER_ERRORS
+
+#ifndef DONT_PRINT_PARSER_ERRORS
+#define EXEC(x) x
+#else
+#define EXEC(x)                                   \
+	stdout = Test::TestSuite::the().outputNull(); \
+	x;                                            \
+	stdout = Test::TestSuite::the().outputStd();
+#endif
+
+std::vector<Json::Token> lex(const std::string& input)
+{
+	EXEC(
+		Json::Job job(input);
+		Json::Lexer lexer(&job);
+		lexer.analyze(););
+	return *job.tokens();
+}
+
+Json::Value parse(const std::string& input)
+{
+	EXEC(
+		Json::Job job(input);
+		Json::Lexer lexer(&job);
+		lexer.analyze(););
+
+	if (!job.success()) {
+		return nullptr;
+	}
+
+	EXEC(
+		Json::Parser parser(&job);
+		Json::Value json = parser.parse(););
+
+	if (!job.success()) {
+		return nullptr;
+	}
+
+	return json;
+}
+
+std::string serialize(const std::string& input, uint32_t indent = 0)
+{
+	EXEC(
+		auto json = Json::Value::parse(input););
+	return json.dump(indent);
+}
+
+// -----------------------------------------
+
+TEST_CASE(JsonLexer)
+{
+	std::vector<Json::Token> tokens;
+
+	// Literal
+
+	tokens = lex("true");
+	EXPECT_EQ(tokens.size(), 1);
+	EXPECT_EQ(tokens[0].symbol, "true");
+	EXPECT(tokens[0].type == Json::Token::Type::Literal);
+
+	tokens = lex("false");
+	EXPECT_EQ(tokens.size(), 1);
+	EXPECT_EQ(tokens[0].symbol, "false");
+	EXPECT(tokens[0].type == Json::Token::Type::Literal);
+
+	tokens = lex("null");
+	EXPECT_EQ(tokens.size(), 1);
+	EXPECT_EQ(tokens[0].symbol, "null");
+	EXPECT(tokens[0].type == Json::Token::Type::Literal);
+
+	// Number
+
+	tokens = lex("3.14");
+	EXPECT_EQ(tokens.size(), 1);
+	EXPECT_EQ(tokens[0].symbol, "3.14");
+	EXPECT(tokens[0].type == Json::Token::Type::Number);
+
+	tokens = lex("-3.14e+2");
+	EXPECT_EQ(tokens.size(), 1);
+	EXPECT_EQ(tokens[0].symbol, "-3.14e+2");
+	EXPECT(tokens[0].type == Json::Token::Type::Number);
+
+	tokens = lex("+3.14");
+	EXPECT_EQ(tokens.size(), 1);
+	EXPECT_EQ(tokens[0].symbol, "+");
+	EXPECT(tokens[0].type == Json::Token::Type::None);
+
+	// String
+
+	tokens = lex(R"("a string")");
+	EXPECT_EQ(tokens.size(), 1);
+	EXPECT_EQ(tokens[0].symbol, "a string");
+	EXPECT(tokens[0].type == Json::Token::Type::String);
+
+	tokens = lex(R"("a string""another string")");
+	EXPECT_EQ(tokens.size(), 2);
+	EXPECT_EQ(tokens[0].symbol, "a string");
+	EXPECT_EQ(tokens[1].symbol, "another string");
+	EXPECT(tokens[0].type == Json::Token::Type::String);
+
+	tokens = lex("\"a string\nwill break on the newline symbol\"");
+	EXPECT_EQ(tokens.size(), 1);
+	EXPECT_EQ(tokens[0].symbol, "a string");
+	EXPECT(tokens[0].type == Json::Token::Type::String);
+
+	// Array
+
+	tokens = lex("[]");
+	EXPECT_EQ(tokens.size(), 2);
+	EXPECT_EQ(tokens[0].symbol, "[");
+	EXPECT_EQ(tokens[1].symbol, "]");
+
+	tokens = lex("[\n\n\n]");
+	EXPECT_EQ(tokens.size(), 2);
+	EXPECT_EQ(tokens[0].symbol, "[");
+	EXPECT_EQ(tokens[1].symbol, "]");
+
+	// Object
+
+	tokens = lex("{}");
+	EXPECT_EQ(tokens.size(), 2);
+	EXPECT_EQ(tokens[0].symbol, "{");
+	EXPECT_EQ(tokens[1].symbol, "}");
+
+	tokens = lex("{\n\n\n}");
+	EXPECT_EQ(tokens.size(), 2);
+	EXPECT_EQ(tokens[0].symbol, "{");
+	EXPECT_EQ(tokens[1].symbol, "}");
+}
+
+TEST_CASE(JsonParser)
+{
+	Json::Value json;
+
+	json = parse("null");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("true");
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::Bool);
+
+	json = parse("false");
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::Bool);
+
+	json = parse("3.14");
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::Number);
+
+	json = parse(R"("a string")");
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::String);
+
+	// Array
+
+	json = parse("[");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("[ 123");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("[ 123,");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("[ 123, ]");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("[ 123 456 ]");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("[]");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Array);
+
+	json = parse(R"([ "element", 3.14 ])");
+	EXPECT_EQ(json.size(), 2);
+	EXPECT_EQ(json.type(), Json::Value::Type::Array);
+
+	// Object
+
+	json = parse("{");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse(R"({ "name")");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse(R"({ "name":)");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse(R"({ "name":,)");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse(R"({ "name":"value")");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse(R"({ "name":"value",)");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse(R"({ "name":"value", })");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse(R"({ "name" "value" })");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse(R"({ 123 })");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("{}");
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Object);
+
+	json = parse(R"({ "name": "value", "name2": 3.14 })");
+	EXPECT_EQ(json.size(), 2);
+	EXPECT_EQ(json.type(), Json::Value::Type::Object);
+
+	// Multiple root elements
+
+	json = parse("54 false");
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("3.14, 666");
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = parse("true\nfalse");
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+}
+
+TEST_CASE(JsonToJsonValue)
+{
+	Json::Value json;
+
+	json = {};
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = nullptr;
+	EXPECT_EQ(json.size(), 0);
+	EXPECT_EQ(json.type(), Json::Value::Type::Null);
+
+	json = true;
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::Bool);
+
+	json = false;
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::Bool);
+
+	json = 666;
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::Number);
+
+	json = 3.14;
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::Number);
+
+	const char* characters = "my string";
+	json = characters;
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::String);
+
+	std::string string = "my string";
+	json = string;
+	EXPECT_EQ(json.size(), 1);
+	EXPECT_EQ(json.type(), Json::Value::Type::String);
+
+	// Nested Array with multiple types
+	json = { "element", 3.14, true, nullptr, { "nested element", { "more nesting", { 1, 2, 3, "yes" } } } };
+	EXPECT_EQ(json.size(), 5);
+	EXPECT_EQ(json.type(), Json::Value::Type::Array);
+
+	// Nested Object with multiple types
+	json = { { "name", "value" }, { "name2", 3.14 }, { "name3", true }, { "name4", nullptr }, { "name5", { { "nested name", "value" } } } };
+	EXPECT_EQ(json.size(), 5);
+	EXPECT_EQ(json.type(), Json::Value::Type::Object);
+
+	// Array with singular type
+	std::vector<std::string> vector = { "element", "element2", "element3" };
+	json = vector;
+	EXPECT_EQ(json.size(), 3);
+	EXPECT_EQ(json.type(), Json::Value::Type::Array);
+
+	// Object with singular type
+	std::map<std::string, std::string> map = { { "name", "value" }, { "name2", "value2" } };
+	json = map;
+	EXPECT_EQ(json.size(), 2);
+	EXPECT_EQ(json.type(), Json::Value::Type::Object);
+
+	// Object with singular type
+	std::unordered_map<std::string, std::string> unorderedMap = { { "name", "value" }, { "name2", "value2" } };
+	json = unorderedMap;
+	EXPECT_EQ(json.size(), 2);
+	EXPECT_EQ(json.type(), Json::Value::Type::Object);
+}
+
+TEST_CASE(JsonFromJsonValue)
+{
+	Json::Value json;
+
+	json = nullptr;
+	EXPECT_EQ(json.get<std::nullptr_t>(), nullptr);
+
+	json = true;
+	EXPECT_EQ(json.get<bool>(), true);
+
+	json = false;
+	EXPECT_EQ(json.get<bool>(), false);
+
+	json = 666;
+	EXPECT_EQ(json.get<int>(), 666);
+
+	json = 3.14;
+	EXPECT_EQ(json.get<double>(), 3.14);
+
+	std::string string;
+	json = "my string";
+	json.getTo(string);
+	EXPECT_EQ(string, "my string");
+	EXPECT_EQ(json.get<std::string>(), "my string");
+
+	// Array with singular type
+	json = { "element", "element2" };
+	EXPECT_EQ(json[0].get<std::string>(), "element");
+	EXPECT_EQ(json.at(1).get<std::string>(), "element2");
+	auto array = json.get<std::vector<std::string>>();
+	EXPECT_EQ(array.size(), 2);
+	EXPECT_EQ(array[0], "element");
+	EXPECT_EQ(array[1], "element2");
+
+	// Array with multiple types
+	json = { "string", 3.14, true, nullptr };
+	EXPECT_EQ(json[0].get<std::string>(), "string");
+	EXPECT_EQ(json.at(1).get<double>(), 3.14);
+	EXPECT_EQ(json[2].get<bool>(), true);
+	EXPECT_EQ(json[3].get<std::nullptr_t>(), nullptr);
+	auto valueArray = json.get<std::vector<Json::Value>>();
+	EXPECT_EQ(valueArray.size(), 4);
+	EXPECT_EQ(valueArray[0].get<std::string>(), "string");
+	EXPECT_EQ(valueArray[1].get<double>(), 3.14);
+	EXPECT_EQ(valueArray[2].get<bool>(), true);
+	EXPECT_EQ(valueArray[3].get<std::nullptr_t>(), nullptr);
+
+	// Nested Array with multiple types
+	json = {
+		"value",
+		{
+			"thing",
+			666,
+		},
+		{
+			{
+				3.14,
+			},
+		}
+	};
+	EXPECT_EQ(json[0].get<std::string>(), "value");
+	EXPECT_EQ(json.at(1)[0].get<std::string>(), "thing");
+	EXPECT_EQ(json[1].at(1).get<int>(), 666);
+	EXPECT_EQ(json[2][0][0].get<double>(), 3.14);
+
+	// Object with singular type
+	json = { { "name", "value" }, { "name2", "value2" } };
+	EXPECT_EQ(json["name"].get<std::string>(), "value");
+	EXPECT_EQ(json.at("name2").get<std::string>(), "value2");
+	auto object = json.get<std::map<std::string, std::string>>();
+	EXPECT_EQ(object.size(), 2);
+	EXPECT_EQ(object["name"], "value");
+	EXPECT_EQ(object["name2"], "value2");
+	auto unorderedObject = json.get<std::unordered_map<std::string, std::string>>();
+	EXPECT_EQ(unorderedObject.size(), 2);
+	EXPECT_EQ(unorderedObject["name"], "value");
+	EXPECT_EQ(unorderedObject["name2"], "value2");
+
+	// Object with multiple types
+	json = { { "name", "value" }, { "name2", 3.14 }, { "name3", true }, { "name4", nullptr } };
+	EXPECT_EQ(json["name"].get<std::string>(), "value");
+	EXPECT_EQ(json.at("name2").get<double>(), 3.14);
+	EXPECT_EQ(json["name3"].get<bool>(), true);
+	EXPECT_EQ(json["name4"].get<std::nullptr_t>(), nullptr);
+	auto valueObject = json.get<std::map<std::string, Json::Value>>();
+	EXPECT_EQ(valueObject.size(), 4);
+	EXPECT_EQ(valueObject["name"].get<std::string>(), "value");
+	EXPECT_EQ(valueObject["name2"].get<double>(), 3.14);
+	EXPECT_EQ(valueObject["name3"].get<bool>(), true);
+	EXPECT_EQ(valueObject["name4"].get<std::nullptr_t>(), nullptr);
+
+	// Nested Object with multiple types
+	json = {
+		{
+			"name",
+			"value",
+		},
+		{
+			"nest 1-deep",
+			{ {
+				"number",
+				1,
+			} },
+		},
+		{
+			"nest 2-deep",
+			{ {
+				"nest 1-deep",
+				{ {
+					"bool",
+					true,
+				} },
+			} },
+		},
+	};
+	EXPECT_EQ(json["name"].get<std::string>(), "value");
+	EXPECT_EQ(json["nest 1-deep"]["number"].get<int>(), 1);
+	EXPECT_EQ(json["nest 2-deep"]["nest 1-deep"]["bool"].get<bool>(), true);
+}
+
+TEST_CASE(JsonImplicitConversion)
+{
+	Json::Value array;
+	array[0];
+	EXPECT_EQ(array.type(), Json::Value::Type::Array);
+
+	Json::Value arrayEmplace;
+	arrayEmplace.emplace_back("element");
+	arrayEmplace.emplace_back({ "nested element" });
+	EXPECT_EQ(arrayEmplace.type(), Json::Value::Type::Array);
+	EXPECT_EQ(arrayEmplace[1].type(), Json::Value::Type::Array);
+
+	Json::Value object;
+	object[""];
+	EXPECT_EQ(object.type(), Json::Value::Type::Object);
+
+	Json::Value objectEmplace;
+	objectEmplace.emplace("name", "value");
+	objectEmplace.emplace("name2", { { "nested name", "value" } });
+	EXPECT_EQ(objectEmplace.type(), Json::Value::Type::Object);
+	EXPECT_EQ(objectEmplace["name2"].type(), Json::Value::Type::Object);
+}
+
+TEST_CASE(JsonSerializer)
+{
+	EXPECT_EQ(serialize(""), "null");
+	EXPECT_EQ(serialize("null"), "null");
+	EXPECT_EQ(serialize("true"), "true");
+	EXPECT_EQ(serialize("false"), "false");
+	EXPECT_EQ(serialize("3.14"), "3.14");
+	EXPECT_EQ(serialize(R"("string")"), R"("string")");
+
+	EXPECT_EQ(serialize("\n\n\n"), "null");
+	EXPECT_EQ(serialize("null\n"), "null");
+	EXPECT_EQ(serialize("true\n"), "true");
+	EXPECT_EQ(serialize("false\n"), "false");
+	EXPECT_EQ(serialize("3.14\n"), "3.14");
+	// clang-format off
+	EXPECT_EQ(serialize(R"("string")" "\n"), R"("string")");
+	// clang-format on
+
+	EXPECT_EQ(serialize("[\n\n\n]"), "[]");
+	EXPECT_EQ(serialize("[null]"), "[null]");
+	EXPECT_EQ(serialize("[true]"), "[true]");
+	EXPECT_EQ(serialize("[false]"), "[false]");
+	EXPECT_EQ(serialize("[3.14]"), "[3.14]");
+	EXPECT_EQ(serialize(R"(["string"])"), R"(["string"])");
+
+	EXPECT_EQ(serialize("[\n\n\n]", 4), "[\n]");
+	EXPECT_EQ(serialize("[null]", 4), "[\n    null\n]");
+	EXPECT_EQ(serialize("[true]", 4), "[\n    true\n]");
+	EXPECT_EQ(serialize("[false]", 4), "[\n    false\n]");
+	EXPECT_EQ(serialize("[3.14]", 4), "[\n    3.14\n]");
+	// clang-format off
+	EXPECT_EQ(serialize(R"(["string"])", 4), "[\n    " R"("string")" "\n]");
+	// clang-format on
+
+	// Check for trailing comma on last array element
+	EXPECT_EQ(serialize(R"([1])"), R"([1])");
+	EXPECT_EQ(serialize(R"([1,2])"), R"([1,2])");
+	EXPECT_EQ(serialize(R"([1,2,3])"), R"([1,2,3])");
+
+	// Check for trailing comma on last object member
+	EXPECT_EQ(serialize(R"({"n1":"v1"})"), R"({"n1":"v1"})");
+	EXPECT_EQ(serialize(R"({"n1":"v1", "n2":"v2"})"), R"({"n1":"v1","n2":"v2"})");
+	EXPECT_EQ(serialize(R"({"n1":"v1", "n2":"v2", "n3":"v3"})"), R"({"n1":"v1","n2":"v2","n3":"v3"})");
+
+	// clang-format off
+	EXPECT_EQ(serialize(R"({
+	"object member one": [
+		"array element one"
+	],
+	"object member two": [
+		"array element one",
+		"array element two"
+	],
+	"object member three": [
+		"array element one",
+		2,
+		3.0,
+		4.56,
+		true,
+		false,
+		null
+	],
+	"object member four": 3.14,
+	"object member five": "value five",
+	"object member six": null,
+	"object member seven": { "no": 0 }
+})", 4), R"({
+    "object member five": "value five",
+    "object member four": 3.14,
+    "object member one": [
+        "array element one"
+    ],
+    "object member seven": {
+        "no": 0
+    },
+    "object member six": null,
+    "object member three": [
+        "array element one",
+        2,
+        3,
+        4.56,
+        true,
+        false,
+        null
+    ],
+    "object member two": [
+        "array element one",
+        "array element two"
+    ]
+})");
+	// clang-format on
+}