functions.cpp

/*
 * Copyright (c) 2015-2023 JlnWntr (jlnwntr@gmail.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

/* #define LUA_ADAPTER_DEBUG */

#ifndef LUA_FUNCTION_H
#include "../LuaFunction.hpp"
#endif
#ifndef LUA_ADAPTER_DEBUG
#include <iostream>
#endif

static int test_function(lua_State *L);

int main() {
    LuaAdapter lua{};
    LuaFunction luaFunction{lua};

    // Define a C/C++-function that can be called from lua (see test.lua)
    if(luaFunction.Push(test_function, "test_function") == false) {
        std::cout << "Could NOT push C-function! \n";
        return 1;
    }

    // THEN load the script:
    lua.Load("test.lua");

    // one argument, no return value
    luaFunction.Call("Print", "This is a string.");
    luaFunction.Call("Print", 1);
    luaFunction.Call("Print", 2.2);
    luaFunction.Call("Print", true);

    // null arguments
    int Return_int{0};
    luaFunction.Call("Random", 0, Return_int);
    std::cout << "Random: " << Return_int << std::endl;


    // one argument, one return value
    const double double_arg {2.3};
    double double_result{};
    const std::string function{"Inc"};
    luaFunction.Call(function, double_arg, double_result);
    std::cout << "Incrementing a double: " << double_result << std::endl;

    // zero arguments, one return value
    std::string Return_string{};
    luaFunction.Call("String", 0, Return_string);
    std::cout << "String-function: " << Return_string << std::endl;

    // three arguments, one return value
    int array[] = {1, 2, 3};
    luaFunction.Call("Sum3", 3, array, Return_int);
    std::cout << "Sum(1, 2, 3) = " << Return_int << std::endl;

    // three arguments, NO return value
    int test1[] = {3, 2, 1};
    luaFunction.Call("Sum3", 3, test1, LUA_ADAPTER_NULL);
    std::cout << "Called Sum3 without return-value.\n";

    // two arguments, one return value
    int test2[] = {36, 24};
    int result{0};
    luaFunction.Call("gcd", 2, test2, result);
    std::cout << "gcd(36, 24) = " << result << std::endl;
    std::cout << std::endl;

    test_function(nullptr); // this is to ignore a compile-warning

    // Check lua's internal stack
    std::cout << "stack top: " << lua.GetTop() << std::endl; // should be 0

    std::cout << "Test ended!\n";
    return 0;
}

/**
 * This C++-function can be called from Lua
 */
static int test_function(lua_State *L) {
    if (not L)
        return 0;
    double number{lua_tonumber(L, 1)};
    number *= 2;
    lua_pushnumber(L, number);
    return 1;
}