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C++和Lua混和调用

news 2025/5/6 6:21:56

为什么要C/C++

流行的语言，学习人员多
高性能，对于嵌入式设备则是省电
大量的第三方库

为什么要Lua

C++缺点：编译慢，调试难，学习难度大
Lua优点：
- 最快的脚本语言
- 可以编译调试
- 与C/C++结合容易
- Lua是对性能有要求的必备脚本

lua基本语法

lua基础数据类型和变量

全局变量

b = 10

局部变量：尽量使用局部变量，保证变量控制

local b = 10

数据类型
- NIL
  - 用于区分具有一些数据或者没有数据的值
  - 全局变量设置为nil会交给垃圾回收
```
local a = nil
print(type(a)) --> nil
```
- Booleans
  - Lua中所有的值都可以作为条件
  - 除了false和nil为假以外，其他的值都为真，0为真
- Numbers
  - Lua中没有整数，都是用浮点数进行运算
  - 对应的c中的double类型
  - 新版中有基于64位的整形
  - tonumber()转换格式
- Strings
  - tostring()格式转换
  - [[]]多行字符串赋值
  - 与C一样转义\
  - …字符串拼接
  - String 处理
    - 字符串长度string.len
    - 字符串子串string.sub(str, 3, 5)
    - 字符串查找local b,e = string.find(str, “HEAD”) 支持正则
    - 字符串替换string.gsub(str, "HEAD, “XCJ”)

lua控制结构语句

条件判断

if 条件语句

if conditions thentehn-part
elseif condition thenelseif-part
else else-part
end

逻辑运算
- and or not
- < > <= >= ~= ==

循环语句

while循环语句

while condition dostatements
end

break 退出循环

repeat循环语句

repeatstatements
until conditions

break 退出循环

for 循环语句

/// 1
for var=from, to, step doloop-part
end
/// 2
for i,v in ipairs(a) do print(v)
end

break 退出循环

lua表和函数

lua表

表的大小 table.getn(t1)
插入 table.insert(a, pos, line)
- 不传pos相当于push_back
删除table.remove(a, pos)返回这次删除的值
- 不传pos相当于pop_back

local tab1 = {"001", "002", "003"}
for i, v in ipairs(tab1) doprint(i..":"..v)
endprint("======= insert =======")
table.insert(tab1, 3, "002-2")table.insert(tab1, "004")
for i, v in ipairs(tab1) doprint(i..":"..v)
endprint("======= remove =======")
table.remove(tab1, 3)
table.remove(tab1)
for i, v in ipairs(tab1) doprint(i..":"..v)
endlocal tab1 = { id = 123, age = 20}
tab1["name"] = "aaa"
print("====== insert ======")
for k, v in pairs(tab1) doprint(k..":"..v)
endprint("====== remove ======")
tab1["id"] = nil
for k, v in pairs(tab1) doprint(k..":"..v)
endprint("====== tab3 ======")
local tab3 = {}tab3[1] = {"1", "2"}tab3[2] = {"3", "4"}
for k, v in pairs(tab3) dofor k2, v2 in pairs(v) doprint(k.."::"..k2..":"..v2)end
end

lua函数

函数语法

function func_name(args)statement-list;
end

function test1(args)print(args)
end
function test2(args)return 1
end
test1(11)
print(test2(11))

lua调用C++

函数调用

#include <iostream>extern "C"
{#include "lua.h"#include "lauxlib.h"#include "lualib.h"
}int test(lua_State* L)
{printf("int test");return 0;
}int main()
{lua_State *L = lua_open();luaopen_base(L);luaopen_string(L);luaopen_table(L);lua_register(L, "test", test);luaL_loadfile(L, "main.lua");lua_pcall(L, 0, 0, 0);return 0;
}

test()

参数传递

传递普通参数

#include <iostream>extern "C"
{#include "lua.h"#include "lauxlib.h"#include "lualib.h"
}int test(lua_State* L)
{printf("int test\n");size_t len;const char* str = lua_tolstring(L, 1, &len);printf("lua args %s\n", str);int age = lua_tointeger(L, 2);printf("lua args %d\n", age);return 0;
}int main()
{lua_State *L = lua_open();luaopen_base(L);luaopen_string(L);luaopen_table(L);lua_register(L, "test", test);luaL_loadfile(L, "main.lua");lua_pcall(L, 0, 0, 0);return 0;
}

test("hello lua", 123)

传递数组

#include <iostream>extern "C"
{#include "lua.h"#include "lauxlib.h"#include "lualib.h"
}int test(lua_State* L)
{printf("int test\n");size_t len;const char* str = lua_tolstring(L, 1, &len);printf("lua args %s\n", str);int age = lua_tointeger(L, 2);printf("lua args %d\n", age);return 0;
}
int test_array(lua_State *L)
{printf("init test_array\n");int len = luaL_getn(L, 1);for (int i = 0; i < len; i++){lua_pushnumber(L, i + 1);lua_gettable(L, 1); // pop idx  push 压入tablesize_t len;printf("%s\n", lua_tolstring(L, -1, &len));lua_pop(L, 1);}return 0;
}int main()
{lua_State *L = lua_open();luaopen_base(L);luaopen_string(L);luaopen_table(L);lua_register(L, "test", test);lua_register(L, "test_array", test_array);luaL_loadfile(L, "main.lua");lua_pcall(L, 0, 0, 0);return 0;
}

local tab = {"001", "002", "003"}
test_array(tab)

传递kv表

int test_array2(lua_State *L)
{printf("init test_array2\n");
//    lua_pushnil(L);
//    while (lua_next(L, 1) != 0)
//    {
//        printf("key = %s\n", lua_tostring(L, -2));
//        printf("value = %s\n", lua_tostring(L, -1));
//        lua_pop(L, 1);
//    }lua_getfield(L, 1, "age");printf("age = %s\n", lua_tostring(L, -1));return 0;
}

local tab = {name="xiaoming", age="22", id="007"}
test_array2(tab)

C++参数类型检查

int test_array2(lua_State *L)
{luaL_checktype(L, 1, LUA_TTABLE);if (lua_type(L, 2) != LUA_TNUMBER){printf("arg2 is not number\n");}printf("init test_array2\n");lua_getfield(L, 1, "age");printf("age = %s\n", lua_tostring(L, -1));return 0;
}

local tab = {name="xiaoming", age="22", id="007"}
local size = "108"
test_array2(tab, size)

返回值获取

C++返回值普通类型

int test_ret(lua_State *L)
{lua_pushstring(L, "test_ret");return 1;
}

print(test_ret())

返回对象

int test_ret(lua_State *L)
{lua_newtable(L);lua_pushstring(L, "name");lua_pushstring(L, "zhangsan");lua_settable(L, -3);lua_pushstring(L, "age");lua_pushnumber(L, 21);lua_settable(L, -3);return 1;
}

tab = test_ret()
print(tab["name"])
print(tab["age"])

C++调用lua

全局变量访问（普通、表）

int main()
{lua_State *L = lua_open();luaopen_base(L);luaopen_string(L);luaopen_table(L);lua_register(L, "test", test);lua_register(L, "test_array", test_array);lua_register(L, "test_array2", test_array2);lua_register(L, "test_ret", test_ret);lua_pushstring(L, "hello");lua_setglobal(L, "test1_hello");lua_newtable(L);lua_pushstring(L, "name");lua_pushstring(L, "lisi");lua_settable(L, -3);lua_setglobal(L, "test1_table");if (luaL_loadfile(L, "main.lua")){const char *error = lua_tostring(L, -1);printf("lua call error: %s\n", error);return -1;}if (lua_pcall(L, 0, 0, 0)){const char *error = lua_tostring(L, -1);printf("lua call error: %s\n", error);return -1;}lua_getglobal(L, "width");int width = lua_tonumber(L, -1);lua_pop(L, 1);printf("width = %d\n", width);lua_getglobal(L, "tab1");lua_getfield(L, -1, "name");printf("%s\n", lua_tostring(L, -1));lua_getfield(L, -2, "age");printf("%d\n", (int)lua_tonumber(L, -1));lua_pop(L, 3);lua_close(L);return 0;
}

width = 20
tab1 = {name="zhangsan", age=20}
print(test1_hello)for i, v in pairs(test1_table) doprint(i..":"..v)
end

函数调用（参数，返回值）

int main()
{lua_State *L = lua_open();luaopen_base(L);luaopen_string(L);luaopen_table(L);lua_register(L, "test", test);lua_register(L, "test_array", test_array);lua_register(L, "test_array2", test_array2);lua_register(L, "test_ret", test_ret);lua_pushstring(L, "hello");lua_setglobal(L, "test1_hello");lua_newtable(L);lua_pushstring(L, "name");lua_pushstring(L, "lisi");lua_settable(L, -3);lua_setglobal(L, "test1_table");if (luaL_loadfile(L, "main.lua")){const char *error = lua_tostring(L, -1);printf("lua call error: %s\n", error);lua_pop(L, 1);}if (lua_pcall(L, 0, 0, 0)){const char *error = lua_tostring(L, -1);printf("lua call error: %s\n", error);lua_pop(L, 1);}lua_getglobal(L, "width");int width = lua_tonumber(L, -1);lua_pop(L, 1);printf("width = %d\n", width);lua_getglobal(L, "tab1");lua_getfield(L, -1, "name");printf("%s\n", lua_tostring(L, -1));lua_getfield(L, -2, "age");printf("%d\n", (int)lua_tonumber(L, -1));lua_pop(L, 3);// 调用函数lua_getglobal(L, "event");lua_pushstring(L, "key");lua_pushstring(L, "value");if (lua_pcall(L, 2, 1, 0) != 0){const char *error = lua_tostring(L, -1);printf("lua call error: %s\n", error);lua_pop(L, 1);}else{printf("lua call error: %s\n", lua_tostring(L, -1));lua_pop(L, 1);}printf("top is %d\n", lua_gettop(L));lua_close(L);return 0;
}

width = 20
tab1 = {name="zhangsan", age=20}
print(test1_hello)for i, v in pairs(test1_table) doprint(i..":"..v)
endfunction event(key, value)print("key:"..key.."  value:"..value)return "aaaaa"
endfunction event(args)for i,v in ipairs(args) doprint("key:"..i.."  value:"..v)end
end