wrenpp/examples/math_vector/main.cpp

/* Copyright 2020-2022, 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/def_configuration.hpp"
#include "wrenpp/vm_fun.hpp"
#include "wrenpp/callback_manager.hpp"
#include "wrenpp/class_manager.hpp"
#include <string_view>
#include <algorithm>
#include <iostream>

namespace {
	constexpr std::string_view g_math_vector_src{
"foreign class MathVector {" R"script(
	construct new() {}
	construct new(value) {}
	construct new(x, y, z) {}

	foreign x
	foreign y
	foreign z

	foreign x=(value)
	foreign y=(value)
	foreign z=(value)

	foreign static base_x()
}
)script"};

	constexpr const char g_test_script[] =
R"script(import "math_vector" for MathVector
var vec1 = MathVector.new(15.0)
var vec2 = MathVector.new(10.0, 20.0, 30.0)
var vec3 = MathVector.new()
System.print("vec1 constructed from single value: <%(vec1.x), %(vec1.y), %(vec1.z)>")
System.print("vec2 constructed from three values: <%(vec2.x), %(vec2.y), %(vec2.z)>")
System.print("vec3 default constructed: <%(vec3.x), %(vec3.y), %(vec3.z)>")

vec3.x = 3.5
vec3.y = vec2.x / vec2.z
vec3.z = vec1.x + vec2.y / 4.0
System.print("vec3 modified by scripting: <%(vec3.x), %(vec3.y), %(vec3.z)>")

var vec_base_x = MathVector.base_x()
System.print("vec_base_x modified by scripting: <%(vec_base_x.x), %(vec_base_x.y), %(vec_base_x.z)>")

)script";

	template <typename T>
	class Vector {
	public:
		Vector() = default;
		explicit Vector (T value) :
			m_x(value), m_y(value), m_z(value)
		{}
		Vector (T x, T y, T z) :
			m_x(x), m_y(y), m_z(z)
		{}
		~Vector() noexcept = default;

		T x() const { return m_x; }
		T y() const { return m_y; }
		T z() const { return m_z; }
		void set_x(T x) { m_x = x; }
		void set_y(T y) { m_y = y; }
		void set_z(T z) { m_z = z; }

		static Vector base_x() { return {1.0, 0.0, 0.0}; }

	private:
		T m_x{}, m_y{}, m_z{};
	};

	class MyConf : public wren::DefConfiguration {
	public:
		char* load_module_fn(wren::VM* vm, std::string_view module_name) {
			if (module_name == "math_vector") {
				constexpr const std::size_t buff_sz = g_math_vector_src.size() + 1;
				char* const buff = new char[buff_sz];
				std::copy(g_math_vector_src.cbegin(), g_math_vector_src.cend(), buff);
				buff[buff_sz - 1] = '\0';
				return buff;
			}
			return nullptr;
		}

		void load_module_complete_fn(wren::VM*, std::string_view, char* buffer) {
			delete[] buffer;
		}
	};
} //unnamed namespace

int main() {
	using wren::make_function_bindable;
	using wren::make_foreign_class;
	using wren::ConstructorParameters;

	MyConf conf;
	wren::VM vm(&conf, nullptr);
	vm.callback_manager()
		.add_callback(false, "math_vector", "MathVector", "x=(_)", make_function_bindable<&Vector<double>::set_x>)
		.add_callback(false, "math_vector", "MathVector", "y=(_)", make_function_bindable<&Vector<double>::set_y>)
		.add_callback(false, "math_vector", "MathVector", "z=(_)", make_function_bindable<&Vector<double>::set_z>)
		.add_callback(false, "math_vector", "MathVector", "x", make_function_bindable<&Vector<double>::x>)
		.add_callback(false, "math_vector", "MathVector", "y", make_function_bindable<&Vector<double>::y>)
		.add_callback(false, "math_vector", "MathVector", "z", make_function_bindable<&Vector<double>::z>)
		.add_callback(true, "math_vector", "MathVector", "base_x()", make_function_bindable<&Vector<double>::base_x>);

	vm.class_manager()
		.add_class_maker("math_vector", "MathVector", make_foreign_class<Vector<double>,
			double, //single value constructor
			ConstructorParameters<double, double, double>, //x,y,z constructor
			ConstructorParameters<> //default constructor
		>);

	vm.interpret("main", g_test_script);

	return 0;
}