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#include <stdio.h>

#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>

int main(int argc, char **argv)
{
    lua_State *L;

    L = luaL_newstate();
    luaL_openlibs(L);
    if (luaL_dofile(L, "counter_test.lua")) {  // 执行lua脚本
        printf("Could not load file: %sn", lua_tostring(L, -1));
        lua_close(L);
        return 0;
    }

    lua_close(L);
    return 0;
}

local M = {}
local M_mt = { __index = M }

function M:new(start)
    if self ~= M then
        return nil, "First argument must be self"  -- 使用冒号调用的方法都会有 self 变量
    end

    local o = setmetatable({}, M_mt)  -- 调用o, 就和调用M一样(__index)
    o._count = start
    return o
end
setmetatable(M, { __call = M.new })  -- 当调用M()时，会实际调用M.new()函数

function M:add(amount)
    self._count = self._count + amount
end

function M:subtract(amount)
    self._count = self._count - amount
end

function M:increment()
    self:add(1)
end

function M:decrement()
    self:subtract(1)
end

function M:getval()
    return self._count
end

function M_mt:__tostring()
    return string.format("%d", self._count)
end

return M

cmod = require("counter")
c = cmod(0)
c:add(4)
c:decrement()
print("val=" .. c:getval())

c:subtract(-2)
c:increment()
print(c)

cmake_minimum_required (VERSION 3.0)
project (lua_embed C)

find_package(Lua REQUIRED)

include_directories (
    ${CMAKE_CURRENT_BINARY_DIR}
    ${CMAKE_CURRENT_SOURCE_DIR}
    ${LUA_INCLUDE_DIR}
)

set (SOURCES
    main.c
)

add_executable (${PROJECT_NAME} ${SOURCES})
target_link_libraries (${PROJECT_NAME} lua dl m)