Lua 5.3 -- SOL2.0 用户指南 【2】

系列教程指南【1】

注意

在你学习了sol的基础知识之后，建议你如果认为某些东西可以运行，你应该尝试一下。它可能会运行！

以下所有代码均可在sol2教程示例中找到。

断言/先决条件

The implementation for assert.hpp with c_assert looks like so:

你需要代码中#include<sol.hpp>#include "sol.hpp"。SOL只有头文件，所以你不需要编译任何东西。但是，Lua必须编译并可用。有关更多详细信息，请参阅入门教程。

assert.hpp 和 c_assert 的实现看起来像这样：

#ifndef EXAMPLES_ASSERT_HPP
#define EXAMPLES_ASSERT_HPP

#   define m_assert(condition, message) \
    do { \
        if (! (condition)) { \
            std::cerr << "Assertion `" #condition "` failed in " << __FILE__ \
                      << " line " << __LINE__ << ": " << message << std::endl; \
            std::terminate(); \
        } \
    } while (false)

#   define c_assert(condition) \
    do { \
        if (! (condition)) { \
            std::cerr << "Assertion `" #condition "` failed in " << __FILE__ \
                      << " line " << __LINE__ << std::endl; \
            std::terminate(); \
        } \
    } while (false)
#else
#   define m_assert(condition, message) do { if (false) { (void)(condition); (void)sizeof(message); } } while (false)
#   define c_assert(condition) do { if (false) { (void)(condition); } } while (false)
#endif

#endif // EXAMPLES_ASSERT_HPP

这是下面示例代码中使用的断言。 

打开状态

#define SOL_CHECK_ARGUMENTS 1
#include <sol.hpp>

#include <iostream>
#include "../../assert.hpp"

int main(int, char*[]) {
	std::cout << "=== opening a state ===" << std::endl;

	sol::state lua;
	// open some common libraries
	lua.open_libraries(sol::lib::base, sol::lib::package);
	lua.script("print('bark bark bark!')");

	std::cout << std::endl;

	return 0;
}

在lua_State上使用sol2 *

对于已经使用Lua或使用其他的Lua系统（LuaBridge，kaguya，Luwra等）的系统/游戏，你仍然会喜欢sol2的：

#define SOL_CHECK_ARGUMENTS 1
#include <sol.hpp>

#include <iostream>

int use_sol2(lua_State* L) {
	sol::state_view lua(L);
	lua.script("print('bark bark bark!')");
	return 0;
}

int main(int, char*[]) {
	std::cout << "=== opening sol::state_view on raw Lua ===" << std::endl;

	lua_State* L = luaL_newstate();
	luaL_openlibs(L);

	lua_pushcclosure(L, &use_sol2, 0);
	lua_setglobal(L, "use_sol2");

	if (luaL_dostring(L, "use_sol2()")) {
		lua_error(L);
		return -1;
	}

	std::cout << std::endl;

	return 0;
}

运行lua代码

#define SOL_CHECK_ARGUMENTS 1
#include <sol.hpp>

#include <fstream>
#include <iostream>
#include "../../assert.hpp"

int main(int, char*[]) {
	std::cout << "=== running lua code ===" << std::endl;

	sol::state lua;
	lua.open_libraries(sol::lib::base);

	// load and execute from string
	lua.script("a = 'test'");
	// load and execute from file
	lua.script_file("a_lua_script.lua");

	// run a script, get the result
	int value = lua.script("return 54");
	c_assert(value == 54);

//要运行Lua代码但需有错误处理程序以防出现问题：

      auto bad_code_result = lua.script("123 herp.derp", [](lua_State*, sol::protected_function_result pfr) {
		// pfr will contain things that went wrong, for either loading or executing the script
		// Can throw your own custom error
		// You can also just return it, and let the call-site handle the error if necessary.
		return pfr;
	});
	// it did not work
	c_assert(!bad_code_result.valid());

	// the default handler panics or throws, depending on your settings
	// uncomment for explosions:
	//auto bad_code_result_2 = lua.script("bad.code", &sol::script_default_on_error);
	return 0;
}

运行lua代码（底层）

您可以使用单独的加载和函数调用操作符来加载，检查，然后运行和检查代码。

警告

这只是在你需要某种细粒度控制的情况下：对于99％的情况，运行lua代码是首选，并避免在不理解脚本/加载与需要在加载后运行块之间的差异时的缺陷。

#define SOL_CHECK_ARGUMENTS 1
#include <sol.hpp>

#include <fstream>
#include <iostream>
#include <cstdio>
#include "../../assert.hpp"

int main(int, char*[]) {
	std::cout << "=== running lua code (low level) ===" << std::endl;

	sol::state lua;
	lua.open_libraries(sol::lib::base);

	// load file without execute
	sol::load_result script1 = lua.load_file("a_lua_script.lua");
	//execute
	script1();

	// load string without execute
	sol::load_result script2 = lua.load("a = 'test'");
	//execute
	sol::protected_function_result script2result = script2();
	// optionally, check if it worked
	if (script2result.valid()) {
		// yay!
	}
	else {
		// aww
	}

	sol::load_result script3 = lua.load("return 24");
	// execute, get return value
	int value2 = script3();
	c_assert(value2 == 24);

	return 0;
}

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