Start working on a c++ interface.

.gitignore

@@ -0,0 +1,2 @@
+tags
+compile_commands.json

meson.build

@@ -8,6 +8,9 @@ wren_dep = dependency('wren', version: '>=0.2.0', fallback: ['wren', 'wren_dep']
 
 executable(meson.project_name(),
   'src/main.cpp',
+  'src/wren/vm.cpp',
+  'src/wren/configuration.cpp',
+  'src/wren/def_configuration.cpp',
   dependencies: [wren_dep],
   install: true,
 )

src/main.cpp

@@ -1,32 +1,18 @@
+#include "wren/vm.hpp"
+#include "wren/def_configuration.hpp"
 #include <iostream>
-#include <wren.hpp>
 #include <chrono>
 #include <thread>
 
 namespace {
-	void wren_print (WrenVM*, const char* text) {
-		std::cout << text;
-	}
-
-	void wren_error (WrenVM*, WrenErrorType type, const char* module, int line, const char* message) {
-		std::cerr << "Wren error: " << message << " in " << module << ':' << line << '\n';
-	}
 } //unnamed namespace
 
 int main() {
 	std::cout << "hello world\n";
-	WrenConfiguration config;
-	wrenInitConfiguration(&config);
-	config.writeFn = &wren_print;
-	config.errorFn = &wren_error;
-	WrenVM* vm = wrenNewVM(&config);
-	WrenInterpretResult result = wrenInterpret(
-		vm,
-		"my_module",
-		"System.print(\"I am running in a VM!\")"
-	);
+	wren::DefConfiguration config;
+	wren::VM vm(&config);
+	vm.interpret("my_module", "System.print(\"I am running in a VM!\")");
 	std::this_thread::sleep_for(std::chrono::milliseconds(2000));
-	wrenFreeVM(vm);
 
 	return 0;
 }

src/wren/configuration.cpp

@@ -0,0 +1,13 @@
+#include "configuration.hpp"
+#include <wren.hpp>
+
+namespace wren {
+	Configuration::Configuration() {
+		WrenConfiguration conf;
+		wrenInitConfiguration(&conf);
+
+		m_initial_heap_size = conf.initialHeapSize;
+		m_min_heap_size = conf.minHeapSize;
+		m_heap_growth_percent = conf.heapGrowthPercent;
+	}
+} //namespace wren

src/wren/configuration.hpp

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <cstddef>
+
+namespace wren {
+	class Configuration {
+	public:
+		Configuration();
+		~Configuration() noexcept = default;
+
+		std::size_t initial_heap_size() const { return m_initial_heap_size; }
+		void set_initial_heap_size(std::size_t v) { m_initial_heap_size = v; }
+
+		std::size_t min_heap_size() const { return m_min_heap_size; }
+		void set_min_heap_size(std::size_t v) { m_min_heap_size = v; }
+
+		std::size_t heap_growth_percent() const { return m_heap_growth_percent; }
+		void set_heap_growth_percent(std::size_t v) { m_heap_growth_percent = v; }
+
+	private:
+		std::size_t m_initial_heap_size;
+		std::size_t m_min_heap_size;
+		std::size_t m_heap_growth_percent;
+	};
+} //namespace wren

src/wren/def_configuration.cpp

@@ -0,0 +1,12 @@
+#include "def_configuration.hpp"
+#include <iostream>
+
+namespace wren {
+	void DefConfiguration::write_fn (VM*, const char* text) {
+		std::cout << text;
+	}
+
+	void DefConfiguration::error_fn (VM*, ErrorType type, const char* module, int line, const char* message) {
+		std::cerr << "Wren error: " << message << " in " << module << ':' << line << '\n';
+	}
+} //namespace wren

src/wren/def_configuration.hpp

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "configuration.hpp"
+#include "error_type.hpp"
+
+namespace wren {
+	class VM;
+
+	class DefConfiguration : public Configuration {
+	public:
+		static void write_fn (VM*, const char* text);
+		static void error_fn (VM*, ErrorType, const char* module, int line, const char* msg);
+	};
+} //namespace wren

src/wren/error_type.hpp

@@ -0,0 +1,14 @@
+#pragma once
+
+namespace wren {
+	enum class ErrorType {
+		// A syntax or resolution error detected at compile time.
+		Compile,
+
+		// The error message for a runtime error.
+		Runtime,
+
+		// One entry of a runtime error's stack trace.
+		StackTrace
+	};
+} //namespace wren

src/wren/has_method.hpp

@@ -0,0 +1,53 @@
+#pragma once
+
+#include <type_traits>
+
+//see https://stackoverflow.com/a/10707822
+#define define_method_info(method_name, pretty_name, ret_type, ...) \
+	class method_ ## pretty_name { \
+		typedef std::integral_constant<int, 0> no_method_t; \
+		typedef std::integral_constant<int, 1> has_method_t; \
+		typedef std::integral_constant<int, 2> has_static_method_t; \
+		template<typename A, typename... Args> \
+		static has_method_t test(ret_type (A::*)(Args...)) { \
+			return {}; \
+		} \
+		template <typename A, typename... Args> \
+		static has_static_method_t test(ret_type (*)(Args...)) { \
+			return {}; \
+		} \
+		template <typename A, typename... Args> \
+		static auto test(decltype(std::declval<A>().method_name(std::declval<Args>()...))*,void *) { \
+			typedef decltype(test<A, Args...>(&A::method_name)) return_type; \
+			return return_type{}; \
+		} \
+		template<typename A, typename... Args> \
+		static no_method_t test(...) { \
+			return {}; \
+		} \
+	public: \
+		template< typename T> \
+		class exists { \
+			typedef decltype(test<T, __VA_ARGS__>(0,0)) found_t; \
+		public: \
+			static const constexpr bool value = (found_t::value != no_method_t::value); \
+		}; \
+		template <typename T> \
+		class is_static { \
+			typedef decltype(test<T, __VA_ARGS__>(0,0)) found_t; \
+		public: \
+			static const constexpr bool value = (found_t::value == has_static_method_t::value); \
+		}; \
+		template <typename T> struct static_ptr { \
+			typedef ret_type (*type)(__VA_ARGS__); \
+		}; \
+		template <typename T> struct nonstatic_ptr { \
+			typedef ret_type (T::*type)(__VA_ARGS__); \
+		}; \
+		template <typename T> struct ptr { \
+			typedef typename std::conditional<is_static<T>::value, typename static_ptr<T>::type, typename std::conditional<exists<T>::value, typename nonstatic_ptr<T>::type, void>::type>::type type; \
+		}; \
+	}
+
+namespace wren {
+} //namespace wren

src/wren/vm.cpp

@@ -0,0 +1,116 @@
+#include "vm.hpp"
+#include "configuration.hpp"
+#include <wren.hpp>
+#include <cassert>
+#include <stdexcept>
+
+namespace wren {
+	namespace {
+		[[gnu::const]]
+		ErrorType to_error_type (WrenErrorType wet) {
+			switch (wet) {
+			case WREN_ERROR_COMPILE: return ErrorType::Compile;
+			case WREN_ERROR_RUNTIME: return ErrorType::Runtime;
+			case WREN_ERROR_STACK_TRACE: return ErrorType::StackTrace;
+			default: return ErrorType::Runtime;
+			};
+		}
+
+		void write_fn (WrenVM* wvm, const char* text) {
+			auto cb = static_cast<detail::Callbacks*>(wrenGetUserData(wvm));
+			assert(cb);
+			assert(cb->write_fn and cb->config_obj and cb->vm);
+			cb->write_fn(*cb->config_obj, cb->vm, text);
+		}
+
+		void error_fn (WrenVM* wvm, WrenErrorType type, const char* module, int line, const char* message) {
+			auto cb = static_cast<detail::Callbacks*>(wrenGetUserData(wvm));
+			assert(cb);
+			assert(cb->error_fn and cb->config_obj and cb->vm);
+			cb->error_fn(*cb->config_obj, cb->vm, to_error_type(type), module, line, message);
+		}
+
+		const char* resolve_module_fn (WrenVM* wvm, const char* importer, const char* name) {
+			auto cb = static_cast<detail::Callbacks*>(wrenGetUserData(wvm));
+			assert(cb);
+			assert(cb->resolve_module_fn and cb->config_obj and cb->vm);
+			return cb->resolve_module_fn(*cb->config_obj, cb->vm, importer, name);
+		}
+
+		char* load_module_fn (WrenVM* wvm, const char* name) {
+			auto cb = static_cast<detail::Callbacks*>(wrenGetUserData(wvm));
+			assert(cb);
+			assert(cb->load_module_fn and cb->config_obj and cb->vm);
+			return cb->load_module_fn(*cb->config_obj, cb->vm, name);
+		}
+	} //unnamed namespace
+
+	VM::VM (Configuration* conf, const detail::Callbacks& cb) :
+		m_callbacks(cb),
+		m_vm(nullptr)
+	{
+		WrenConfiguration wconf;
+		wrenInitConfiguration(&wconf);
+		wconf.userData = static_cast<void*>(&m_callbacks);
+
+		wconf.initialHeapSize = conf->initial_heap_size();
+		wconf.minHeapSize = conf->min_heap_size();
+		wconf.heapGrowthPercent = conf->heap_growth_percent();
+
+		if (cb.write_fn)
+			wconf.writeFn = &write_fn;
+
+		if (cb.error_fn)
+			wconf.errorFn = &error_fn;
+
+		if (cb.reallocate_fn)
+			wconf.reallocateFn = cb.reallocate_fn;
+
+		if (cb.resolve_module_fn)
+			wconf.resolveModuleFn = &resolve_module_fn;
+
+		if (cb.load_module_fn)
+			wconf.loadModuleFn = &load_module_fn;
+
+		m_vm = wrenNewVM(&wconf);
+
+		if (not m_vm)
+			throw std::runtime_error("Failed to initialize Wren VM");
+	}
+
+	VM::VM (VM&& other) :
+		m_vm(nullptr)
+	{
+		std::swap(m_vm, other.m_vm);
+		m_callbacks = other.m_callbacks;
+		wrenSetUserData(m_vm, &m_callbacks);
+	}
+
+	VM::~VM() noexcept {
+		if (m_vm)
+			wrenFreeVM(m_vm);
+#if !defined(NDEBUG)
+		m_vm = nullptr;
+#endif
+	}
+
+	void VM::interpret (const char* module_name, const char* script) {
+		using std::string;
+		using std::runtime_error;
+
+		const WrenInterpretResult res = wrenInterpret(m_vm, module_name, script);
+		switch (res) {
+		case WREN_RESULT_COMPILE_ERROR:
+			throw runtime_error(string("Compilation of ") + module_name + " has failed");
+		case WREN_RESULT_RUNTIME_ERROR:
+			throw runtime_error(string("A runtime error occurred in ") + module_name);
+
+		case WREN_RESULT_SUCCESS:
+			break;
+		}
+	}
+
+	void VM::interpret (const std::string& module_name, const std::string& script) {
+		return interpret(module_name.c_str(), script.c_str());
+	}
+} //namespace wren

src/wren/vm.hpp

@@ -0,0 +1,125 @@
+#pragma once
+
+#include "has_method.hpp"
+#include "error_type.hpp"
+#include <string>
+
+extern "C" {
+	typedef struct WrenVM WrenVM;
+} //extern C
+
+namespace wren {
+	class Configuration;
+	class VM;
+
+	namespace detail {
+		struct Callbacks {
+			void (*write_fn)(Configuration&, VM*, const char*);
+			void (*error_fn)(Configuration&, VM*, ErrorType, const char*, int, const char*);
+			void* (*reallocate_fn)(void*, std::size_t);
+			const char* (*resolve_module_fn)(Configuration&, VM*, const char*, const char*);
+			char* (*load_module_fn)(Configuration&, VM*, const char*);
+
+			Configuration* config_obj;
+			VM* vm;
+		};
+	} //namespace detail
+
+	class VM {
+	public:
+		template <typename T>
+		VM (T* conf);
+		VM (const VM&) = delete;
+		VM (VM&& other);
+		~VM() noexcept;
+
+		void interpret (const char* module_name, const char* script);
+		void interpret (const std::string& module_name, const std::string& script);
+
+	private:
+		VM (Configuration* conf, const detail::Callbacks&);
+
+		template <typename T>
+		detail::Callbacks to_callbacks (T& conf);
+
+		detail::Callbacks m_callbacks;
+		WrenVM* m_vm;
+	};
+
+	namespace detail {
+		define_method_info(write_fn, write, void, VM*, const char*);
+		define_method_info(error_fn, error, void, VM*, ErrorType, const char*, int, const char*);
+		define_method_info(reallocate_fn, reallocate, void*, void*, std::size_t);
+		define_method_info(resolve_module_fn, resolve_module, const char*, const char*, const char*);
+		define_method_info(load_module_fn, load_module, char*, VM*, const char*);
+
+		namespace fwd {
+			template <typename T>
+			inline void write_fn (Configuration& obj, VM* vm, const char* text) {
+				reinterpret_cast<T&>(obj).write_fn(vm, text);
+			}
+
+			template <typename T>
+			inline void error_fn (Configuration& obj, VM* vm, ErrorType et, const char* module, int line, const char* message) {
+				reinterpret_cast<T&>(obj).error_fn(vm, et, module, line, message);
+			}
+
+			template <typename T>
+			inline const char* resolve_module_fn (Configuration& obj, VM* vm, void* memory, std::size_t new_size) {
+				return reinterpret_cast<T&>(obj).resolve_module_fn(vm, memory, new_size);
+			}
+
+			template <typename T>
+			inline char* load_module_fn (Configuration& obj, VM* vm, const char* name) {
+				return reinterpret_cast<T&>(obj).load_module_fn(vm, name);
+			}
+		} //namespace fwd
+	} //namespace detail
+
+	template <typename T>
+	inline detail::Callbacks VM::to_callbacks (T& conf) {
+		using detail::method_write;
+		using detail::method_error;
+		using detail::method_reallocate;
+		using detail::method_resolve_module;
+		using detail::method_load_module;
+
+		detail::Callbacks ret;
+		ret.config_obj = &conf;
+		ret.vm = this;
+
+		if constexpr (method_write::exists<T>::value)
+			ret.write_fn = &detail::fwd::write_fn<T>;
+		else
+			ret.write_fn = nullptr;
+
+		if constexpr (method_error::exists<T>::value)
+			ret.error_fn = &detail::fwd::error_fn<T>;
+		else
+			ret.error_fn = nullptr;
+
+		if constexpr (method_reallocate::exists<T>::value and method_reallocate::is_static<T>::value)
+			ret.reallocate_fn = &T::reallocate_fn;
+		else
+			ret.reallocate_fn = nullptr;
+		static_assert(not method_reallocate::exists<T>::value or method_reallocate::is_static<T>::value, "Realloc function must be a static function");
+
+		if constexpr (method_resolve_module::exists<T>::value)
+			ret.resolve_module_fn = &detail::fwd::resolve_module_fn<T>;
+		else
+			ret.resolve_module_fn = nullptr;
+
+		if constexpr (method_load_module::exists<T>::value)
+			ret.load_module_fn = &detail::fwd::load_module_fn<T>;
+		else
+			ret.load_module_fn = nullptr;
+
+		return ret;
+	}
+
+	template <typename T>
+	inline VM::VM (T* conf) :
+		VM(static_cast<Configuration*>(conf), to_callbacks(*conf))
+	{
+	}
+} //namespace wren