Add support for object parameters to Wren calls

examples/call_cpp/main.cpp

@@ -0,0 +1,175 @@
+/* Copyright 2020-2024, Michele Santullo
+ * This file is part of wrenpp.
+ *
+ * Wrenpp is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Wrenpp is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with wrenpp.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "wrenpp/vm_fun.hpp"
+#include "wrenpp/def_configuration.hpp"
+#include "wrenpp/callback_manager.hpp"
+#include "wrenpp/class_manager.hpp"
+#include <chrono>
+#include <thread>
+#include <iostream>
+
+namespace {
+constexpr char g_module_a[] =
+"foreign class ClassA {" R"script(
+	construct new(msg) {
+		System.print("Wren ClassA constructed")
+	}
+
+	foreign say_hi()
+}
+)script";
+
+constexpr char g_module_b[] = ""
+R"script(
+import "module_a" for ClassA
+
+foreign class ClassB {
+	construct new(nickname) {
+		System.print("Wren ClassB constructed")
+	}
+
+	do_action(obj_a, times) {
+		System.print("Wren ClassB is doing its action %(times) times...")
+		for (z in 1..times) {
+			obj_a.say_hi()
+		}
+		greeting_message("John", "Doe", "\\(O.O)/")
+	}
+
+	foreign greeting_message(first_name, family_name, emoji)
+}
+)script";
+
+//This is three examples in one:
+//1. instantiate ClassA in Wren and pass it to do_action() which is a
+//   non-foreign method in wren
+//2. instantiate ClassA in C++, have C++ invoke the non-foreign method
+//   do_action() on the object obj_b from the previous execution and pass the
+//   C++ instance of ClassA to it
+//3. instantiate ClassB in C++, have C++ invoke the non-foreign method
+//   do_action() on it and pass the same ClassA instance from the previous
+//   step to it
+constexpr char g_script[] = ""
+R"script(
+import "module_a" for ClassA
+import "module_b" for ClassB
+
+var obj_b = ClassB.new("TheWren")
+obj_b.do_action(ClassA.new("instanciated from script"), 2)
+obj_b.greeting_message("Jane", "Doe", "ʕ·͡ᴥ·ʔ")
+)script";
+
+class MyWrenConfig : public wren::DefConfiguration {
+public:
+	char* load_module_fn (wren::VM* vm, std::string_view module_name) {
+		if (module_name == "module_a")
+			return copied(g_module_a, sizeof(g_module_a));
+		else if (module_name == "module_b")
+			return copied(g_module_b, sizeof(g_module_b));
+		return nullptr;
+	}
+
+	void load_module_complete_fn (wren::VM* vm, std::string_view module_name, char* buff) {
+		static_cast<void>(vm);
+		static_cast<void>(module_name);
+		delete[] buff;
+	}
+
+private:
+	char* copied (const char* source, std::size_t len) {
+		char* const buff = new char[len];
+		std::copy(source, source + len / sizeof(source[0]), buff);
+		return buff;
+	}
+};
+
+struct ClassA {
+	explicit ClassA (std::string msg) : m_message(msg) {
+		std::cout << "C++ ClassA constructed\n";
+	}
+	ClassA (const ClassA&) = delete;
+	ClassA (ClassA&&) = delete;
+
+	void say_hi() {
+		std::cout << "C++ ClassA says \"" << m_message << "\"!\n";
+	}
+
+	std::string m_message;
+};
+
+class ClassB {
+public:
+	explicit ClassB (std::string nickname) : m_nickname(nickname) {
+		std::cout << "C++ ClassB constructed\n";
+	}
+
+	ClassB (const ClassB&) = delete;
+	ClassB (ClassB&&) = delete;
+
+	void greeting_message (
+		std::string_view first_name,
+		const char* family_name,
+		const std::string& emoji
+	) {
+		std::cout << "C++ ClassB says \"hello " << first_name << " '"  <<
+			m_nickname << "' " << family_name << "\" " << emoji << '\n';
+	}
+
+private:
+	std::string m_nickname;
+};
+} //unnamed namespace
+
+int main() {
+	using wren::make_function_bindable;
+	using wren::make_foreign_class;
+	using wren::make_wren_object;
+
+	//We need a custom one to deal with custom module loading for
+	//module_a and module_b
+	MyWrenConfig config;
+	wren::VM vm(&config, nullptr);
+
+
+	vm.callback_manager()
+		.add_callback(false, "module_a", "ClassA", "say_hi()", make_function_bindable<&ClassA::say_hi>)
+		.add_callback(false, "module_b", "ClassB", "greeting_message(_,_,_)", make_function_bindable<&ClassB::greeting_message>)
+	;
+	vm.class_manager()
+		.add_class_maker("module_b", "ClassB", make_foreign_class<ClassB, std::string>)
+		.add_class_maker("module_a", "ClassA", make_foreign_class<ClassA, std::string>)
+	;
+
+	//Example 1: invoke obj_b.do_action() from Wren passing an obj_a that's
+	//also instantiated from within the Wren script
+	vm.interpret("main", g_script);
+
+	//Example 2: invoke obj_b.do_action() from C++ passing a new obj_a which
+	//is instantiated from C++
+	wren::ForeignObject<ClassA> obj_a = make_wren_object<ClassA>(vm, wren::MN<"module_a", "ClassA">, "instantiated from c++");
+	wren::call<void>(vm, wren::MN<"main", "obj_b">, "do_action", obj_a, 3);
+
+	//Example 3: invoke obj_b.do_action() from C++, where obj_b is also
+	//instantiated from C++, and pass the C++ obj_a instance to it
+	auto obj_b = make_wren_object<ClassB>(vm, wren::MN<"module_b", "ClassB">, "TheCpp");
+	wren::call<void>(vm, obj_b, "do_action", obj_a, 4);
+
+	std::cout << "Quitting in 1 sec" << std::endl;
+	std::this_thread::sleep_for(std::chrono::milliseconds(1000));
+	return 0;
+}

examples/call_cpp/meson.build

@@ -0,0 +1,5 @@
+executable('call_cpp',
+  'main.cpp',
+  dependencies: wrenpp_dep,
+  install: false,
+)

examples/greet/main.cpp

@@ -1,4 +1,4 @@
-/* Copyright 2020-2022, Michele Santullo
+/* Copyright 2020-2024, Michele Santullo
  * This file is part of wrenpp.
  *
  * Wrenpp is free software: you can redistribute it and/or modify
@@ -63,8 +63,6 @@ void user_get_env (wren::VM& vm, wren::ModuleAndName) {
 } //unnamed namespace
 
 int main() {
-	//typedef wren::ModuleAndName MN;
-
 	wren::DefConfiguration config;
 	wren::VM vm(&config, nullptr);
 	vm.callback_manager().add_callback(true, "main", "User", "get_env(_)", [](){return &user_get_env;});

examples/meson.build

@@ -2,3 +2,4 @@ subdir('dieroll')
 subdir('greet')
 subdir('calendar')
 subdir('math_vector')
+subdir('call_cpp')

include/wrenpp/detail/foreign_object.hpp

@@ -0,0 +1,63 @@
+/* Copyright 2020-2024, Michele Santullo
+ * This file is part of wrenpp.
+ *
+ * Wrenpp is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Wrenpp is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with wrenpp.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "wrenpp/handle.hpp"
+#include <utility>
+
+namespace wren {
+
+template <typename T>
+class ForeignObject {
+public:
+	ForeignObject() = default;
+	ForeignObject (std::nullptr_t) : ForeignObject() {}
+	ForeignObject (T* obj, Handle&& handle);
+	~ForeignObject() noexcept = default;
+
+	void set_to_slot (int num);
+	T& object() { return *m_object; }
+	const T& object() const { return *m_object; }
+	Handle& handle() { return m_handle; }
+	const Handle& handle() const { return m_handle; }
+	bool is_valid() const { return nullptr != m_object; }
+
+	operator T&() { return object(); }
+	operator const T&() const { return object(); }
+	operator Handle&() { return handle(); }
+	operator const Handle&() const { return handle(); }
+	bool operator!= (std::nullptr_t) const { return nullptr != m_object; }
+	bool operator== (std::nullptr_t) const { return nullptr == m_object; }
+
+private:
+	Handle m_handle;
+	T* m_object{nullptr};
+};
+
+template <typename T>
+inline ForeignObject<T>::ForeignObject (T* obj, Handle&& handle) :
+	m_handle(std::move(handle)),
+	m_object(obj)
+{ }
+
+template <typename T>
+inline void ForeignObject<T>::set_to_slot (int num) {
+	m_handle.set_to_slot(num);
+}
+
+} //namespace wren

include/wrenpp/detail/setters_getters.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2020-2022, Michele Santullo
+/* Copyright 2020-2024, Michele Santullo
  * This file is part of wrenpp.
  *
  * Wrenpp is free software: you can redistribute it and/or modify
@@ -18,6 +18,7 @@
 #pragma once
 
 #include "../vm.hpp"
+#include "../handle.hpp"
 #include "module_and_name.hpp"
 #include <string_view>
 #include <vector>
@@ -87,6 +88,8 @@ namespace wren {
 	void set (VM& vm, int slot_num, const char* beg, const char* end);
 	void set (VM& vm, int slot_num, int value);
 	void set (VM& vm, int slot_num, std::size_t value);
+	void set (VM& vm, int slot_num, const Handle& handle);
+	void set (VM& vm, int slot_num, const ModuleAndName& name);
 	std::string_view slot_string_view (VM& vm, int slot_num);
 	template <typename T> detail::GetTypeToRetType_t<T> get (VM& vm, int slot_num);
 	template <typename T> T* foreign (VM& vm, int slot_num);
@@ -138,6 +141,14 @@ namespace wren {
 		vm.set_slot_double(slot_num, static_cast<double>(value));
 	}
 
+	inline void set (VM& vm, int slot_num, const Handle& handle) {
+		vm.set_slot_handle(handle, slot_num);
+	}
+
+	inline void set (VM& vm, int slot_num, const ModuleAndName& name) {
+		vm.variable_or_throw(name.module_name_char(), name.class_name_char(), slot_num);
+	}
+
 	template <typename T>
 	inline T* foreign (VM& vm, int slot_num) {
 		T* obj = static_cast<T*>(vm.slot_foreign(slot_num));

include/wrenpp/handle.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2020-2022, Michele Santullo
+/* Copyright 2020-2024, Michele Santullo
  * This file is part of wrenpp.
  *
  * Wrenpp is free software: you can redistribute it and/or modify
@@ -42,6 +42,8 @@ namespace wren {
 		operator WrenHandle*() const { return m_handle; }
 		operator bool() const { return nullptr != m_handle; }
 
+		void set_to_slot (int num);
+
 	private:
 		WrenHandle* m_handle;
 		VM* m_vm;

include/wrenpp/vm_fun.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2020-2022, Michele Santullo
+/* Copyright 2020-2024, Michele Santullo
  * This file is part of wrenpp.
  *
  * Wrenpp is free software: you can redistribute it and/or modify
@@ -26,6 +26,7 @@
 #include "detail/construct_foreign_class.hpp"
 #include "detail/setters_getters.hpp"
 #include "detail/wren_class_name_from_type.hpp"
+#include "detail/foreign_object.hpp"
 #include <string>
 #include <string_view>
 #include <type_traits>
@@ -46,11 +47,11 @@ namespace wren {
 	R call (VM& vm, ModuleAndName object, const char (&method)[N], const Args&... args);
 
 	template <typename T, typename... Args>
-	T* make_wren_object(VM& vm, ModuleAndName mn, Args&&... args);
+	ForeignObject<T> make_wren_object(VM& vm, ModuleAndName mn, Args&&... args);
 
 #if defined(WRENPP_WITH_NAME_GUESSING)
 	template <typename T, dhandy::bt::string Mod, typename... Args>
-	T* make_wren_object(VM& vm, Args&&... args);
+	ForeignObject<T> make_wren_object(VM& vm, Args&&... args);
 #endif
 
 	void interpret (VM& vm, const std::string& module_name, const std::string& script);
@@ -61,28 +62,13 @@ namespace wren {
 	void abort_fiber_with_error (VM& vm, int slot, std::string_view message);
 
 	namespace detail {
-		template <typename T>
-		inline void set_single_for_call (VM& vm, int slot, const T& value) {
-			set(vm, slot, value);
-		}
-
-		template <>
-		inline void set_single_for_call (VM& vm, int slot_num, const Handle& handle) {
-			vm.set_slot_handle(handle, slot_num);
-		}
-
-		template <>
-		inline void set_single_for_call (VM& vm, int slot_num, const ModuleAndName& name) {
-			variable(vm, name, slot_num);
-		}
-
 		//Sets arguments so wren is ready to perform a function call. It doesn't
 		//touch at slot 0, so eventual objects for method calls must be set
 		//manually
 		template <typename... Args, int... Indices>
 		inline void set_for_call (std::integer_sequence<int, Indices...>, VM& vm, const Args&... args) {
 			vm.ensure_slots(sizeof...(Args));
-			(set_single_for_call(vm, Indices + 1, args), ...);
+			(set(vm, Indices + 1, args), ...);
 		}
 
 		template <auto V>
@@ -145,7 +131,7 @@ namespace wren {
 						}
 						else {
 							ModuleAndName wren_name = wren_class_name_from_type<R>(vm);
-							R* const new_object = make_wren_object<R>(vm, wren_name, std::move(ret));
+							ForeignObject<R> new_object = make_wren_object<R>(vm, wren_name, std::move(ret));
 							static_cast<void>(new_object);
 						}
 					}
@@ -197,15 +183,13 @@ namespace wren {
 	inline R call (VM& vm, const Handle& object, const char (&method)[N], const Args&... args) {
 		using dhandy::bt::string;
 
-		const constexpr char dummy_name_buff[N] = {0};
-		const constexpr auto params = string<N, char>(dummy_name_buff) +
-			string("(") +
+		const constexpr auto params = string("(") +
 			((static_cast<void>(args), string(",_")) + ... + string("")).template substr<1>() +
 			string(")");
 		;
-		char cat_buff[params.size() + 1];
+		char cat_buff[params.size() + 1 + N - 1];
 		std::copy(method, method + N - 1, cat_buff);
-		std::copy(params.data() + N - 1, params.data() + params.size() + 1, cat_buff + N - 1);
+		std::copy(params.data(), params.data() + params.size() + 1, cat_buff + N - 1);
 		return call<R, Args...>(vm, object, vm.make_call_handle(cat_buff), args...);
 	}
 
@@ -218,12 +202,12 @@ namespace wren {
 	}
 
 	template <typename T, typename... Args>
-	inline T* make_wren_object(VM& vm, ModuleAndName mn, Args&&... args) {
-		variable(vm, mn, 0);
+	inline ForeignObject<T> make_wren_object(VM& vm, ModuleAndName mn, Args&&... args) {
+		variable_ensure_slot(vm, mn, 0);
 		void* const mem = vm.set_slot_new_foreign(0, 0, sizeof(T));
 		try {
 			T* const obj = new(mem) T{std::forward<Args>(args)...};
-			return obj;
+			return {obj, vm.slot_handle(0)};
 		}
 		catch (const std::runtime_error& err) {
 			abort_fiber_with_error(vm, 1, err.what());
@@ -233,7 +217,7 @@ namespace wren {
 
 #if defined(WRENPP_WITH_NAME_GUESSING)
 	template <typename T, dhandy::bt::string Mod, typename... Args>
-	inline T* make_wren_object(VM& vm, Args&&... args) {
+	inline ForeignObject<T> make_wren_object(VM& vm, Args&&... args) {
 		return make_wren_object<T>(
 			vm,
 			MN<Mod, g_guessed_class_name<T>>,

src/handle.cpp

@@ -1,4 +1,4 @@
-/* Copyright 2020-2022, Michele Santullo
+/* Copyright 2020-2024, Michele Santullo
  * This file is part of wrenpp.
  *
  * Wrenpp is free software: you can redistribute it and/or modify
@@ -18,6 +18,7 @@
 #include "wrenpp/handle.hpp"
 #include "wrenpp/vm.hpp"
 #include <cassert>
+#include <ciso646>
 
 namespace wren {
 	Handle::~Handle() noexcept {
@@ -25,7 +26,12 @@ namespace wren {
 	}
 
 	void Handle::release() noexcept {
-		assert(m_vm);
-		m_vm->release_handle(*this);
+		assert(m_vm or not m_handle);
+		if (m_vm)
+			m_vm->release_handle(*this);
+	}
+
+	void Handle::set_to_slot (int slot) {
+		m_vm->set_slot_handle(*this, slot);
 	}
 } //namespace wren