14 files changed, 375 insertions, 217 deletions

diff --git a/src/crepe/util/CMakeLists.txt b/src/crepe/util/CMakeLists.txt
index 3675bee..94ed906 100644
--- a/src/crepe/util/CMakeLists.txt
+++ b/src/crepe/util/CMakeLists.txt
@@ -1,12 +1,15 @@
 target_sources(crepe PUBLIC
 	LogColor.cpp
-	log.cpp
-	fmt.cpp
+	Log.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	LogColor.h
-	log.h
-	fmt.h
+	Log.h
+	Log.hpp
+	Proxy.h
+	Proxy.hpp
+	OptionalRef.h
+	OptionalRef.hpp
 )
 
diff --git a/src/crepe/util/Log.cpp b/src/crepe/util/Log.cpp
new file mode 100644
index 0000000..84d80a8
--- /dev/null
+++ b/src/crepe/util/Log.cpp
@@ -0,0 +1,37 @@
+#include <iostream>
+#include <string>
+
+#include "../api/Config.h"
+
+#include "Log.h"
+
+using namespace crepe;
+using namespace std;
+
+string Log::prefix(const Level & level) {
+	switch (level) {
+		case Level::TRACE:
+			return LogColor().fg_white().str("[TRACE]") + " ";
+		case Level::DEBUG:
+			return LogColor().fg_magenta().str("[DEBUG]") + " ";
+		case Level::INFO:
+			return LogColor().fg_blue().str("[INFO]") + " ";
+		case Level::WARNING:
+			return LogColor().fg_yellow().str("[WARN]") + " ";
+		case Level::ERROR:
+			return LogColor().fg_red().str("[ERROR]") + " ";
+	}
+	return "";
+}
+
+void Log::log(const Level & level, const string & msg) {
+	auto & cfg = Config::get_instance();
+	if (level < cfg.log.level) return;
+
+	string out = Log::prefix(level) + msg;
+	if (!out.ends_with("\n")) out += "\n";
+
+	// TODO: also log to file or smth
+	cout.write(out.data(), out.size());
+	cout.flush();
+}
diff --git a/src/crepe/util/Log.h b/src/crepe/util/Log.h
new file mode 100644
index 0000000..fc0bb3a
--- /dev/null
+++ b/src/crepe/util/Log.h
@@ -0,0 +1,84 @@
+#pragma once
+
+#include <format>
+
+// allow user to disable debug macros
+#ifndef CREPE_DISABLE_MACROS
+
+#include "LogColor.h"
+
+// utility macros
+#define _crepe_logf_here(level, fmt, ...) \
+	crepe::Log::logf(level, "{}" fmt, \
+					 crepe::LogColor().fg_white(false).str(std::format( \
+						 "{} ({}:{})", __PRETTY_FUNCTION__, __FILE_NAME__, __LINE__)), \
+					 __VA_ARGS__)
+
+// very illegal global function-style macros
+// NOLINTBEGIN
+#define dbg_logf(fmt, ...) _crepe_logf_here(crepe::Log::Level::DEBUG, ": " fmt, __VA_ARGS__)
+#define dbg_log(str) _crepe_logf_here(crepe::Log::Level::DEBUG, ": {}", str)
+#define dbg_trace() _crepe_logf_here(crepe::Log::Level::TRACE, "", "")
+// NOLINTEND
+
+#endif
+
+namespace crepe {
+
+/**
+ * \brief Logging utility
+ *
+ * This class is used to output log messages to the console and/or log files.
+ */
+class Log {
+public:
+	//! Log message severity
+	enum Level {
+		TRACE, //!< Include (internal) function calls
+		DEBUG, //!< Include dbg_logf output
+		INFO, //!< General-purpose messages
+		WARNING, //!< Non-fatal errors
+		ERROR, //!< Fatal errors
+	};
+
+	/**
+	 * \brief Log a formatted message
+	 *
+	 * \param level Message severity
+	 * \param msg Formatted message
+	 */
+	static void log(const Level & level, const std::string & msg);
+
+	/**
+	 * \brief Format a message and log it
+	 *
+	 * \param level Message severity
+	 * \param fmt Message format
+	 * \param args Format arguments
+	 */
+	template <class... Args>
+	static void logf(const Level & level, std::format_string<Args...> fmt, Args &&... args);
+
+	/**
+	 * \brief Format a message and log it (with default severity \c INFO)
+	 *
+	 * \param fmt Message format
+	 * \param args Format arguments
+	 */
+	template <class... Args>
+	static void logf(std::format_string<Args...> fmt, Args &&... args);
+
+private:
+	/**
+	 * \brief Output a message prefix depending on the log level
+	 *
+	 * \param level Message severity
+	 *
+	 * \return Colored message severity prefix string
+	 */
+	static std::string prefix(const Level & level);
+};
+
+} // namespace crepe
+
+#include "Log.hpp"
diff --git a/src/crepe/util/Log.hpp b/src/crepe/util/Log.hpp
new file mode 100644
index 0000000..c2156cd
--- /dev/null
+++ b/src/crepe/util/Log.hpp
@@ -0,0 +1,17 @@
+#pragma once
+
+#include "Log.h"
+
+namespace crepe {
+
+template <class... Args>
+void Log::logf(std::format_string<Args...> fmt, Args &&... args) {
+	Log::logf(Level::INFO, fmt, std::forward<Args>(args)...);
+}
+
+template <class... Args>
+void Log::logf(const Level & level, std::format_string<Args...> fmt, Args &&... args) {
+	Log::log(level, std::format(fmt, std::forward<Args>(args)...));
+}
+
+} // namespace crepe
diff --git a/src/crepe/util/LogColor.cpp b/src/crepe/util/LogColor.cpp
index b5fe3ea..5411898 100644
--- a/src/crepe/util/LogColor.cpp
+++ b/src/crepe/util/LogColor.cpp
@@ -1,16 +1,15 @@
 #include <cstdarg>
 
 #include "../api/Config.h"
-#include "LogColor.h"
 
-#include "fmt.h"
+#include "LogColor.h"
 
 using namespace crepe;
 using namespace std;
 
 static constexpr const char * RESET_CODE = "\e[0m";
 
-const string LogColor::str(const string & content) {
+const string LogColor::str(const string & content) const {
 	auto & cfg = Config::get_instance();
 	string out = content;
 	if (cfg.log.color) out = this->code + out;
@@ -19,21 +18,8 @@ const string LogColor::str(const string & content) {
 	return out;
 }
 
-const char * LogColor::c_str(const char * content) {
-	this->final = this->str(content == NULL ? "" : content);
-	return this->final.c_str();
-}
-
-const char * LogColor::fmt(const char * fmt, ...) {
-	va_list args;
-	va_start(args, fmt);
-	string content = va_stringf(args, fmt);
-	va_end(args);
-	return this->c_str(content.c_str());
-}
-
 LogColor & LogColor::add_code(unsigned int code) {
-	this->code += stringf("\e[%dm", code);
+	this->code += format("\e[{}m", code);
 	return *this;
 }
 
@@ -42,51 +28,19 @@ LogColor & LogColor::reset() {
 	return *this;
 }
 
-LogColor & LogColor::fg_black(bool bright) {
-	return this->add_code(bright ? 90 : 30);
-}
-LogColor & LogColor::fg_red(bool bright) {
-	return this->add_code(bright ? 91 : 31);
-}
-LogColor & LogColor::fg_green(bool bright) {
-	return this->add_code(bright ? 92 : 32);
-}
-LogColor & LogColor::fg_yellow(bool bright) {
-	return this->add_code(bright ? 93 : 33);
-}
-LogColor & LogColor::fg_blue(bool bright) {
-	return this->add_code(bright ? 94 : 34);
-}
-LogColor & LogColor::fg_magenta(bool bright) {
-	return this->add_code(bright ? 95 : 35);
-}
-LogColor & LogColor::fg_cyan(bool bright) {
-	return this->add_code(bright ? 96 : 36);
-}
-LogColor & LogColor::fg_white(bool bright) {
-	return this->add_code(bright ? 97 : 37);
-}
-LogColor & LogColor::bg_black(bool bright) {
-	return this->add_code(bright ? 100 : 40);
-}
-LogColor & LogColor::bg_red(bool bright) {
-	return this->add_code(bright ? 101 : 41);
-}
-LogColor & LogColor::bg_green(bool bright) {
-	return this->add_code(bright ? 102 : 42);
-}
-LogColor & LogColor::bg_yellow(bool bright) {
-	return this->add_code(bright ? 103 : 43);
-}
-LogColor & LogColor::bg_blue(bool bright) {
-	return this->add_code(bright ? 104 : 44);
-}
-LogColor & LogColor::bg_magenta(bool bright) {
-	return this->add_code(bright ? 105 : 45);
-}
-LogColor & LogColor::bg_cyan(bool bright) {
-	return this->add_code(bright ? 106 : 46);
-}
-LogColor & LogColor::bg_white(bool bright) {
-	return this->add_code(bright ? 107 : 47);
-}
+LogColor & LogColor::fg_black(bool bright) { return this->add_code(bright ? 90 : 30); }
+LogColor & LogColor::fg_red(bool bright) { return this->add_code(bright ? 91 : 31); }
+LogColor & LogColor::fg_green(bool bright) { return this->add_code(bright ? 92 : 32); }
+LogColor & LogColor::fg_yellow(bool bright) { return this->add_code(bright ? 93 : 33); }
+LogColor & LogColor::fg_blue(bool bright) { return this->add_code(bright ? 94 : 34); }
+LogColor & LogColor::fg_magenta(bool bright) { return this->add_code(bright ? 95 : 35); }
+LogColor & LogColor::fg_cyan(bool bright) { return this->add_code(bright ? 96 : 36); }
+LogColor & LogColor::fg_white(bool bright) { return this->add_code(bright ? 97 : 37); }
+LogColor & LogColor::bg_black(bool bright) { return this->add_code(bright ? 100 : 40); }
+LogColor & LogColor::bg_red(bool bright) { return this->add_code(bright ? 101 : 41); }
+LogColor & LogColor::bg_green(bool bright) { return this->add_code(bright ? 102 : 42); }
+LogColor & LogColor::bg_yellow(bool bright) { return this->add_code(bright ? 103 : 43); }
+LogColor & LogColor::bg_blue(bool bright) { return this->add_code(bright ? 104 : 44); }
+LogColor & LogColor::bg_magenta(bool bright) { return this->add_code(bright ? 105 : 45); }
+LogColor & LogColor::bg_cyan(bool bright) { return this->add_code(bright ? 106 : 46); }
+LogColor & LogColor::bg_white(bool bright) { return this->add_code(bright ? 107 : 47); }
diff --git a/src/crepe/util/LogColor.h b/src/crepe/util/LogColor.h
index c1170cb..132fb94 100644
--- a/src/crepe/util/LogColor.h
+++ b/src/crepe/util/LogColor.h
@@ -4,23 +4,35 @@
 
 namespace crepe {
 
+/**
+ * \brief Utility class for coloring text using ANSI escape codes
+ *
+ * \note Most methods in this class return a reference to \c this, which may be
+ * used to chain multiple display attributes.
+ */
 class LogColor {
 public:
-	LogColor() = default;
+	/**
+	 * \brief Get color code as STL string
+	 *
+	 * \param content If given, color this string and append a color reset escape sequence.
+	 *
+	 * \returns Color escape sequence
+	 */
+	const std::string str(const std::string & content = "") const;
 
 public:
-	//! get color code as c-style string (or color content string)
-	const char * c_str(const char * content = NULL);
-	//! color printf-style format string
-	const char * fmt(const char * fmt, ...);
-	//! get color code as stl string (or color content string)
-	const std::string str(const std::string & content = "");
-
-public:
-	//! reset color to default foreground and background color
+	//! Reset color to default foreground and background color
 	LogColor & reset();
 
 public:
+	/**
+	 * \name Foreground colors
+	 *
+	 * These functions set the foreground (text) color. The \c bright parameter
+	 * makes the color brighter, or bold on some terminals.
+	 * \{
+	 */
 	LogColor & fg_black(bool bright = false);
 	LogColor & fg_red(bool bright = false);
 	LogColor & fg_green(bool bright = false);
@@ -29,8 +41,16 @@ public:
 	LogColor & fg_magenta(bool bright = false);
 	LogColor & fg_cyan(bool bright = false);
 	LogColor & fg_white(bool bright = false);
+	/// \}
 
 public:
+	/**
+	 * \name Background colors
+	 *
+	 * These functions set the background color. The \c bright parameter makes
+	 * the color brighter.
+	 * \{
+	 */
 	LogColor & bg_black(bool bright = false);
 	LogColor & bg_red(bool bright = false);
 	LogColor & bg_green(bool bright = false);
@@ -39,13 +59,22 @@ public:
 	LogColor & bg_magenta(bool bright = false);
 	LogColor & bg_cyan(bool bright = false);
 	LogColor & bg_white(bool bright = false);
+	/// \}
 
 private:
+	/**
+	 * \brief Append SGR escape sequence to \c this->code
+	 *
+	 * \param code SGR attribute number
+	 *
+	 * See <https://en.wikipedia.org/wiki/ANSI_escape_code> for magic number
+	 * reference.
+	 */
 	LogColor & add_code(unsigned int code);
 
 private:
+	//! Color escape sequence
 	std::string code = "";
-	std::string final = "";
 };
 
 } // namespace crepe
diff --git a/src/crepe/util/OptionalRef.h b/src/crepe/util/OptionalRef.h
new file mode 100644
index 0000000..1b2cb3f
--- /dev/null
+++ b/src/crepe/util/OptionalRef.h
@@ -0,0 +1,66 @@
+#pragma once
+
+namespace crepe {
+
+/**
+ * \brief Optional reference utility
+ *
+ * This class doesn't need to know the full definition of \c T to be used.
+ *
+ * \tparam T Value type
+ */
+template <typename T>
+class OptionalRef {
+public:
+	//! Initialize empty (nonexistant) reference
+	OptionalRef() = default;
+	//! Initialize reference with value
+	OptionalRef(T & ref);
+	/**
+	 * \brief Assign new reference
+	 *
+	 * \param ref Reference to assign
+	 *
+	 * \return Reference to this (required for operator)
+	 */
+	OptionalRef<T> & operator=(T & ref);
+	/**
+	 * \brief Retrieve this reference (cast)
+	 *
+	 * \returns Internal reference if it is set
+	 *
+	 * \throws std::runtime_error if this function is called while the reference it not set
+	 */
+	operator T &() const;
+	/**
+	 * \brief Retrieve this reference (member access)
+	 *
+	 * \returns Internal reference if it is set
+	 *
+	 * \throws std::runtime_error if this function is called while the reference it not set
+	 */
+	T * operator->() const;
+	/**
+	 * \brief Check if this reference is not empty
+	 *
+	 * \returns `true` if reference is set, or `false` if it is not
+	 */
+	explicit operator bool() const noexcept;
+
+	/**
+	 * \brief Make this reference empty
+	 */
+	void clear() noexcept;
+
+private:
+	/**
+	 * \brief Reference to the value of type \c T
+	 *
+	 * \note This raw pointer is *not* managed, and only used as a reference!
+	 */
+	T * ref = nullptr;
+};
+
+} // namespace crepe
+
+#include "OptionalRef.hpp"
diff --git a/src/crepe/util/OptionalRef.hpp b/src/crepe/util/OptionalRef.hpp
new file mode 100644
index 0000000..5e36b3a
--- /dev/null
+++ b/src/crepe/util/OptionalRef.hpp
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <stdexcept>
+
+#include "OptionalRef.h"
+
+namespace crepe {
+
+template <typename T>
+OptionalRef<T>::OptionalRef(T & ref) {
+	this->ref = &ref;
+}
+
+template <typename T>
+OptionalRef<T>::operator T &() const {
+	if (this->ref == nullptr)
+		throw std::runtime_error("OptionalRef: attempt to dereference nullptr");
+	return *this->ref;
+}
+
+template <typename T>
+T * OptionalRef<T>::operator->() const {
+	if (this->ref == nullptr)
+		throw std::runtime_error("OptionalRef: attempt to dereference nullptr");
+	return this->ref;
+}
+
+template <typename T>
+OptionalRef<T> & OptionalRef<T>::operator=(T & ref) {
+	this->ref = &ref;
+	return *this;
+}
+
+template <typename T>
+OptionalRef<T>::operator bool() const noexcept {
+	return this->ref != nullptr;
+}
+
+template <typename T>
+void OptionalRef<T>::clear() noexcept {
+	this->ref = nullptr;
+}
+
+} // namespace crepe
diff --git a/src/crepe/util/Proxy.h b/src/crepe/util/Proxy.h
new file mode 100644
index 0000000..789144a
--- /dev/null
+++ b/src/crepe/util/Proxy.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include "ValueBroker.h"
+
+namespace crepe {
+
+/**
+ * \brief Utility wrapper for \c ValueBroker
+ *
+ * This class can be used to to wrap a ValueBroker instance so it behaves like a regular
+ * variable.
+ *
+ * \tparam T  Type of the underlying variable
+ */
+template <typename T>
+class Proxy {
+public:
+	//! Set operator
+	Proxy & operator=(Proxy &);
+	//! Set operator
+	Proxy & operator=(const T &);
+	//! Get operator
+	operator const T &();
+
+public:
+	Proxy(ValueBroker<T>);
+
+private:
+	ValueBroker<T> broker;
+};
+
+} // namespace crepe
+
+#include "Proxy.hpp"
diff --git a/src/crepe/util/Proxy.hpp b/src/crepe/util/Proxy.hpp
new file mode 100644
index 0000000..ef2b69f
--- /dev/null
+++ b/src/crepe/util/Proxy.hpp
@@ -0,0 +1,27 @@
+#pragma once
+
+#include "Proxy.h"
+
+namespace crepe {
+
+template <typename T>
+Proxy<T>::Proxy(ValueBroker<T> broker) : broker(broker) {}
+
+template <typename T>
+Proxy<T> & Proxy<T>::operator=(const T & val) {
+	this->broker.set(val);
+	return *this;
+}
+
+template <typename T>
+Proxy<T> & Proxy<T>::operator=(Proxy & proxy) {
+	this->broker.set(T(proxy));
+	return *this;
+}
+
+template <typename T>
+Proxy<T>::operator const T &() {
+	return this->broker.get();
+}
+
+} // namespace crepe
diff --git a/src/crepe/util/fmt.cpp b/src/crepe/util/fmt.cpp
deleted file mode 100644
index 4b50da8..0000000
--- a/src/crepe/util/fmt.cpp
+++ /dev/null
@@ -1,35 +0,0 @@
-#include <cstdarg>
-#include <cstdio>
-#include <string>
-
-#include "fmt.h"
-
-using namespace std;
-
-string crepe::va_stringf(va_list args, const char * fmt) {
-	string out;
-
-	va_list args_copy;
-	va_copy(args_copy, args);
-	size_t length = vsnprintf(NULL, 0, fmt, args_copy);
-	// resize to include terminating null byte
-	out.resize(length + 1);
-	va_end(args_copy);
-
-	// vsnprintf adds terminating null byte
-	vsnprintf(out.data(), out.size(), fmt, args);
-	// resize to actual length
-	out.resize(length);
-
-	va_end(args);
-
-	return out;
-}
-
-string crepe::stringf(const char * fmt, ...) {
-	va_list args;
-	va_start(args, fmt);
-	string out = va_stringf(args, fmt);
-	va_end(args);
-	return out;
-}
diff --git a/src/crepe/util/fmt.h b/src/crepe/util/fmt.h
deleted file mode 100644
index e319e6e..0000000
--- a/src/crepe/util/fmt.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#pragma once
-
-#include <string>
-
-namespace crepe {
-
-std::string va_stringf(va_list args, const char * fmt);
-std::string stringf(const char * fmt, ...);
-
-} // namespace crepe
diff --git a/src/crepe/util/log.cpp b/src/crepe/util/log.cpp
deleted file mode 100644
index 4a8f8e8..0000000
--- a/src/crepe/util/log.cpp
+++ /dev/null
@@ -1,53 +0,0 @@
-#include <cstdarg>
-#include <cstdio>
-#include <cstdlib>
-#include <string>
-
-#include "../api/Config.h"
-#include "fmt.h"
-#include "log.h"
-
-using namespace crepe;
-using namespace std;
-
-string log_prefix(LogLevel level) {
-	switch (level) {
-		case LogLevel::TRACE:
-			return LogColor().fg_white().str("[TRACE]") + " ";
-		case LogLevel::DEBUG:
-			return LogColor().fg_magenta().str("[DEBUG]") + " ";
-		case LogLevel::INFO:
-			return LogColor().fg_blue().str("[INFO]") + " ";
-		case LogLevel::WARNING:
-			return LogColor().fg_yellow().str("[WARN]") + " ";
-		case LogLevel::ERROR:
-			return LogColor().fg_red().str("[ERROR]") + " ";
-	}
-	return "";
-}
-
-static void log(LogLevel level, const string msg) {
-	auto & cfg = Config::get_instance();
-	if (level < cfg.log.level) return;
-
-	string out = log_prefix(level) + msg;
-	if (!out.ends_with("\n")) out += "\n";
-
-	// TODO: also log to file or smth
-	fwrite(out.c_str(), 1, out.size(), stdout);
-	fflush(stdout);
-}
-
-void crepe::logf(const char * fmt, ...) {
-	va_list args;
-	va_start(args, fmt);
-	log(LogLevel::DEBUG, va_stringf(args, fmt));
-	va_end(args);
-}
-
-void crepe::logf(LogLevel level, const char * fmt, ...) {
-	va_list args;
-	va_start(args, fmt);
-	log(level, va_stringf(args, fmt));
-	va_end(args);
-}
diff --git a/src/crepe/util/log.h b/src/crepe/util/log.h
deleted file mode 100644
index 5a1cf00..0000000
--- a/src/crepe/util/log.h
+++ /dev/null
@@ -1,39 +0,0 @@
-#pragma once
-
-// allow user to disable debug macros
-#ifndef CREPE_DISABLE_MACROS
-
-#include "LogColor.h"
-
-// utility macros
-#define _crepe_logf_here(level, format, ...) \
-	crepe::logf( \
-		level, "%s" format, \
-		crepe::LogColor().fg_white(false).fmt( \
-			"%s (%s:%d)", __PRETTY_FUNCTION__, __FILE_NAME__, __LINE__), \
-		__VA_ARGS__)
-
-// very illegal global function-style macros
-// NOLINTBEGIN
-#define dbg_logf(fmt, ...) \
-	_crepe_logf_here(crepe::LogLevel::DEBUG, ": " fmt, __VA_ARGS__)
-#define dbg_log(str) _crepe_logf_here(crepe::LogLevel::DEBUG, "%s: " str, "")
-#define dbg_trace() _crepe_logf_here(crepe::LogLevel::TRACE, "%s", "")
-// NOLINTEND
-
-#endif
-
-namespace crepe {
-
-enum LogLevel {
-	TRACE,
-	DEBUG,
-	INFO,
-	WARNING,
-	ERROR,
-};
-
-void logf(const char * fmt, ...);
-void logf(enum LogLevel level, const char * fmt, ...);
-
-} // namespace crepe