wrenpp/examples/greet/main.cpp

/* Copyright 2020, 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 <chrono>
#include <thread>
#include <unistd.h>

#if defined(__GNU_LIBRARY__) && ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 17) || __GLIBC__ > 2)
#	define HasSecureGetenv
#endif

namespace {
	const constexpr char g_script[] = ""
R"script(class User {
	construct new(nm) {
		_name = nm
	}

	foreign static get_env(name)

	greet() {
		System.print("Hello %(_name), from wren script!")
	}
}

var the_user = User.new(User.get_env("USER"))
)script";

const char* raw_fetch_env (const char* name) noexcept {
	if (not name)
		return nullptr;

#if defined(HasSecureGetenv)
	const char* const val_ptr = secure_getenv(name);
#else
	const char* const val_ptr = getenv(name);
#endif

	return val_ptr;
}

void user_get_env (wren::VM& vm) {
	set(vm, 0, raw_fetch_env(wren::get<const char*>(vm, 1)));
}

class MyConfig : public wren::DefConfiguration {
public:
	wren::foreign_method_t foreign_method_fn (
		wren::VM* vm,
		const char* module_ptr,
		const char* class_name_ptr,
		bool is_static,
		const char* signature_ptr
	) {
		//std::cout << "VM " << vm << " requested foreign method " << class_name << "::" << signature << " in module " << module << "\n";
		std::string_view module(module_ptr);
		std::string_view class_name(class_name_ptr);
		std::string_view signature(signature_ptr);
		if ("User" == class_name and "main" == module and "get_env(_)" == signature)
			return &user_get_env;

		return nullptr;
	}
};
} //unnamed namespace

int main() {
	//typedef wren::ModuleAndName MN;

	MyConfig config;
	wren::VM vm(&config, nullptr);
	vm.interpret("main", g_script);

	wren::call<void>(vm, {"main", "the_user"}, "greet");

	std::cout << "Quitting in 1 sec" << std::endl;
	std::this_thread::sleep_for(std::chrono::milliseconds(1000));
	return 0;
}