Added Embedding Lua Video #1

EmbeddingLua1.lua

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+
+--	Embedding Lua in C++ Part #1
+--	"Stupid 3D printer, I didn't want a nest..." - javidx9
+--
+--	License (OLC-3)
+--	~~~~~~~~~~~~~~~
+--
+--	Copyright 2018-2019 OneLoneCoder.com
+--
+--	Redistribution and use in source and binary forms, with or without
+--	modification, are permitted provided that the following conditions
+--	are met:
+--
+--	1. Redistributions or derivations of source code must retain the above
+--	copyright notice, this list of conditions and the following disclaimer.
+--
+--	2. Redistributions or derivative works in binary form must reproduce
+--	the above copyright notice. This list of conditions and the following
+--	disclaimer must be reproduced in the documentation and/or other
+--	materials provided with the distribution.
+--
+--	3. Neither the name of the copyright holder nor the names of its
+--	contributors may be used to endorse or promote products derived
+--	from this software without specific prior written permission.
+--
+--	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+--	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+--	LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+--	A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+--	HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+--	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+--	LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+--	DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+--	THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+--	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+--	OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+--
+--	Relevant Video: https://youtu.be/4l5HdmPoynw
+--
+--	Links
+--	~~~~~
+--	YouTube:	https://www.youtube.com/javidx9
+--				https://www.youtube.com/javidx9extra
+--	Discord:	https://discord.gg/WhwHUMV
+--	Twitter:	https://www.twitter.com/javidx9
+--	Twitch:		https://www.twitch.tv/javidx9
+--	GitHub:		https://www.github.com/onelonecoder
+--	Patreon:	https://www.patreon.com/javidx9
+--	Homepage:	https://www.onelonecoder.com
+--
+--	Author
+--	~~~~~~
+--	David Barr, aka javidx9, ©OneLoneCoder 2019
+
+
+
+-- Stage 1: Reading Simple Values
+a = 5
+b = 7
+c = a + b
+d = "OneLoneCoder.com"
+
+-- Stage 2: Reading a simple object
+player = {Title = "Squire", Name = "Ciaran", Family = "Wirral", Level = 20}
+
+-- Stage 3: Calling a Lua Function
+function CalledFromCPP1(r1, r2, r3)
+	io.write("[LUA S3] CalledFromCPP1("..r1..", "..r2..", "..r3..")\n")
+	return r1 * r2
+end
+
+-- Stage 4: Calling a C++ Function
+function CalledFromCPP2(r1, r2)
+	io.write("[LUA S4] CalledFromCPP2("..r1..", "..r2..")\n")
+	io.write("[LUA S4] Calling HostFunction("..r1..", "..r2..")\n")
+	r = HostFunction(r1, r2)
+	io.write("[LUA S4] HostFunction returned "..r.."\n")
+	return r * 15
+end
+

OneLoneCoder_EmbeddingLua_Part1.cpp

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+/*
+	Embedding Lua in C++ Part #1
+	"Stupid 3D printer, I didn't want a nest..." - javidx9
+
+	License (OLC-3)
+	~~~~~~~~~~~~~~~
+
+	Copyright 2018-2019 OneLoneCoder.com
+
+	Redistribution and use in source and binary forms, with or without
+	modification, are permitted provided that the following conditions
+	are met:
+
+	1. Redistributions or derivations of source code must retain the above
+	copyright notice, this list of conditions and the following disclaimer.
+
+	2. Redistributions or derivative works in binary form must reproduce
+	the above copyright notice. This list of conditions and the following
+	disclaimer must be reproduced in the documentation and/or other
+	materials provided with the distribution.
+
+	3. Neither the name of the copyright holder nor the names of its
+	contributors may be used to endorse or promote products derived
+	from this software without specific prior written permission.
+
+	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+	LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+	A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+	HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+	LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+	DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+	THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+	OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+	Relevant Video: https://youtu.be/4l5HdmPoynw
+
+	Links
+	~~~~~
+	YouTube:	https://www.youtube.com/javidx9
+				https://www.youtube.com/javidx9extra
+	Discord:	https://discord.gg/WhwHUMV
+	Twitter:	https://www.twitter.com/javidx9
+	Twitch:		https://www.twitch.tv/javidx9
+	GitHub:		https://www.github.com/onelonecoder
+	Patreon:	https://www.patreon.com/javidx9
+	Homepage:	https://www.onelonecoder.com
+
+	Author
+	~~~~~~
+	David Barr, aka javidx9, ©OneLoneCoder 2019
+*/
+
+#include <iostream>
+#include <string>
+
+// include Lua, assumes it is local to this file
+extern "C"
+{
+#include "lua535/include/lua.h"
+#include "lua535/include/lauxlib.h"
+#include "lua535/include/lualib.h"
+}
+
+// Link to lua library
+#ifdef _WIN32
+#pragma comment(lib, "lua535/liblua53.a")
+#endif
+
+
+// Little error checking utility function
+bool CheckLua(lua_State *L, int r)
+{
+	if (r != LUA_OK)
+	{
+		std::string errormsg = lua_tostring(L, -1);
+		std::cout << errormsg << std::endl;
+		return false;
+	}
+	return true;
+}
+
+
+int lua_HostFunction(lua_State *L)
+{
+	float a = (float)lua_tonumber(L, 1);
+	float b = (float)lua_tonumber(L, 2);
+	std::cout << "[CPP S4] HostFunction(" << a << ", " << b << ") called from Lua" << std::endl;
+	float c = a * b;
+	lua_pushnumber(L, c);
+	return 1;
+}
+
+
+// NOTE !!!
+// YOU WILL NEED THE "EmbeddingLua1.lua" FILE FROM GITHUB REPO
+
+
+int main()
+{
+
+	struct Player
+	{
+		std::string title;
+		std::string name;
+		std::string family;
+		int level;
+	} player;
+
+	// Create Lua State
+	lua_State *L = luaL_newstate();
+
+	// Add standard libraries to Lua Virtual Machine
+	luaL_openlibs(L);
+
+	// Register our C++ Function in the global Lua space
+	lua_register(L, "HostFunction", lua_HostFunction);
+
+
+	// Load and parse the Lua File
+	if(CheckLua(L, luaL_dofile(L, "EmbeddingLua1.lua")))
+	{ 
+		// Stage 1: Just read simple variables
+		std::cout << "[CPP] Stage 1 - Read Simple Variables" << std::endl;
+		lua_getglobal(L, "a");
+		if (lua_isnumber(L, -1)) std::cout << "[CPP S1] a = " << (int)lua_tointeger(L, -1) << std::endl;
+		lua_getglobal(L, "b");
+		if (lua_isnumber(L, -1)) std::cout << "[CPP S1] b = " << (int)lua_tointeger(L, -1) << std::endl;
+		lua_getglobal(L, "c");
+		if (lua_isnumber(L, -1)) std::cout << "[CPP S1] c = " << (int)lua_tointeger(L, -1) << std::endl;
+		lua_getglobal(L, "d");
+		if (lua_isstring(L, -1)) std::cout << "[CPP S1] d = " << lua_tostring(L, -1) << std::endl << std::endl;
+
+		// Stage 2: Read Table Object
+		std::cout << "[CPP] Stage 2 - Read Table (Key/Value pairs)" << std::endl;
+		lua_getglobal(L, "player");
+		if (lua_istable(L, -1))
+		{
+			lua_pushstring(L, "Name");
+			lua_gettable(L, -2);
+			player.name = lua_tostring(L, -1);
+			lua_pop(L, 1);
+
+			lua_pushstring(L, "Family");
+			lua_gettable(L, -2);
+			player.family = lua_tostring(L, -1);
+			lua_pop(L, 1);
+
+			lua_pushstring(L, "Title");
+			lua_gettable(L, -2);
+			player.title = lua_tostring(L, -1);
+			lua_pop(L, 1);
+
+			lua_pushstring(L, "Level");
+			lua_gettable(L, -2);
+			player.level = (int)lua_tointeger(L, -1);
+			lua_pop(L, 1);
+		}
+		std::cout << "[CPP S2] " << player.title << " " << player.name << " of " << player.family << " [Lvl: " << player.level << "]" << std::endl << std::endl; 
+
+		// Stage 3: Call Lua Function
+		std::cout << "[CPP] Stage 3 - Call Lua Function" << std::endl;
+		lua_getglobal(L, "CalledFromCPP1");
+		if (lua_isfunction(L, -1))
+		{
+			lua_pushnumber(L, 5.0f);
+			lua_pushnumber(L, 6.0f);
+			lua_pushstring(L, "Bwa ha ha!");
+			std::cout << "[CPP S3] Calling 'CalledFromCPP1' in lua script" << std::endl;
+			if (CheckLua(L, lua_pcall(L, 3, 1, 0)))
+			{
+				std::cout << "[CPP S3] 'CalledFromCPP1' returned " << (float)lua_tonumber(L, -1) << std::endl << std::endl;
+			}
+		}
+
+		// Stage 4: Call Lua Function, which calls C++ Function
+		std::cout << "[CPP] Stage 4 - Call Lua Function, whcih in turn calls C++ Function" << std::endl;
+		lua_getglobal(L, "CalledFromCPP2");
+		if (lua_isfunction(L, -1))
+		{
+			lua_pushnumber(L, 5.0f);
+			lua_pushnumber(L, 6.0f);
+			std::cout << "[CPP S4] Calling 'CalledFromCPP2' in lua script" << std::endl;
+			if (CheckLua(L, lua_pcall(L, 2, 1, 0)))
+			{
+				std::cout << "[CPP S4] 'CalledFromCPP2' returned " << (float)lua_tonumber(L, -1) << std::endl << std::endl;
+			}
+		}
+	}
+
+
+
+
+
+	system("pause");
+	lua_close(L);
+	return 0;
+}