Embedding Lua in C++ Part 3: Meh... Just use Sol...
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- čas přidán 28. 03. 2024
- In this video, I show how to use the excelent Sol library/wrapper to integrate Lua in your C++ program. This is shown in direct contrast to how i did it in Part #1 which was bare bones, from scratch.
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Yeah, Javid's channel is a core part of a C++ programmer's toolbelt at this point. Not only are you videos calming and laid back (something that's hard to find these days), but you also have A LOT of interesting ideas in terms of projects. I can't tell you how many project ideas of yours I... uhhh... "borrowed" and implemented my own way. So, as a young programmer and a C++ connoisseur, thank you. And rock on!
Rock on Frodo! 😂
it's rare these days that someone says "a lot", so I wanted to hi 5 you for that 👍
@@phutureproof Yeah I like saying a lot a lot.
Sol is one of the first libraries where I realized modern C++ can be used to create great APIs; I was almost skeptical when I assigned C++ functions or objects to tables and it just worked on the other side without me needing to explicitly tell it much. A lot of other host languages can't eliminate huge chunks of the boilerplate in the same way because they don't have the same template machinery and type information that C++ does.
and it's a total template hell, but it's still great :D
@@outsider1stI think the complexity is partly historical. It can be made simpler however. Eg. Type packs are awesome but also pretty complex, I made my own TypeList class to help me interrogate and iterate over types. I think, incremental improvements is the way to go, at least with C++.
This video and Sol libraries are just so clear and easy to comprehend that I want to go back to my old c++ project and implement Lua scripting just for the fun of it ;-)
Woooow. Happy to see OLC here. I hope family and you are doing well!
Doing great thanks!
Oh, I've been waiting for this! So thrilled to see more new videos on the channel, they're so informative and fun to watch. Hope that you are doing great.
Ugh, I love this series and your CZcams videos. I don’t know how to show any more appreciation other than just my words
Great video! Sol library sure is greatly simplifying and unconfusinating the embedding of LUA to C++ for the programmer. Thank you Javid for sharing.
Always nice to see a OLC video and learn something. I hope you're well and thanks for making these when you have time
It's nice to see a software video today that isn't talking about the ssh backdoor that just came to light. Thank you Javid, I greatly appreciate your upload and hope that you're doing well!
All the best Javid, thank you very much for your great work you did.
Sol is such a great wrapper for Lua, I can't imagine using Lua without it.
On God, I didn't want to deal with embedding Lua. Sol was basically just plug and play
Sol is a great name for a Lua wrapper. It means "sun" in portuguese, and Lua means "moon"
Being able to just index into the table instead of having to play with the stack looks so useful
This video came at the perfect time as I've just started making my own game engine. I was about the use the raw Lua C libraries but my word Sol is so intuitive!
Love your channel mate!
Very nice, i was not aware of the Sol library. This will come in handy :)
I have been using sol for years now and it's always a pleasure to use.
Better call Sol. Sorry I had to
Give this man a proper drink! I salute you sir!
It's Sol Goodman wrapper at Lua
Thanks Javidx9
can believe the series updated
Nice you do video again... 🎉
Don’t have time to watch today, just dropped to like and comment❤
He is back guys!
LOL i was just re-watching this series for some embeding ideas i was having XD
Very interesting library! Just wish you had shown off in that last segment what happens if lua gives in somethign invalid
sol2 is almost too good to be true
shoutouts to thePhD
Excuse me, i have a question for your previous video about cross platform c++ GUI framework which is called wxwidgets,i do not quite understand the whole rendering principle behind,i mean how can i control my rendering fps?using wxTimer or idleEvent?could you please tell me in detail about it,it really means a lot to me,because i have devoted so much time in investigating this framework including watching your video over and over agagin !!!!!!!!!!!!!!!!!!!!!!
7:00 to print exception.what() to std output, do you have to wrap it into a string? I didn't know that... I would have hoped it already could print a char* just by itself. You live, you learn!!
You don't have to. I looked up sol::error::what and it returns const char* which you can print directly to cout. I don't know why he casts it
I love lua :)
Great video and I have a question. Is there a way to have code completion in Lua? Like if you create a function in c++ and call it from Lua.
Thanks! I'm not aware personally of any IDE that would be that sophisticated. It gets tricky because you can effectively create lua things at runtime, so the code completion would be partial at best.
didn’t realize that part 1 was 5 years ago, and had to scroll forever in the recent videos to find it 😅
You said in Part 2 a few years ago you would show in Part 3 how to use smart pointers in embedded lua. Does this video or any of your other videos show any examples?
Hi Javid, I can't find an example of what I am looking for. I want a C++ engine to run and display a game world. And computer player AI(s) written in a scripting language to be able to query the current game state and then tell the C++ engine what it wants to do. It can be turn based or real time. For example an author can write an AI to play Risk. It can then be an interesting opponent to have in the game or it can be entered in a tournament of other AIs. Or an online RPG can allow people to submit an NPC AI. It could be a villain or maybe 'someone' that can be hired to help the human player. The possibilities are endless and I wonder why it has not been done? Or has it?
I've never used Sol in a project(not a C++ guy), but I'M very familiar with the regular Lua C API. But for best performance you should probably avoid non-standard library C function calls like the pest: When using LuaJIT the Lua and standard library functions are incredibly fast to call, since the compiler doesn't need to emit actual ABI calls, it can inline most functionality. Another trick somewhat related to that is using the LuaJIT FFI; Not to call C functions(since it also is slow due to ABI), but rather for it's data types. You can create C types(integers, pointers, arrays etc.), and access to those is really efficient(can be inlined by LuaJIT). My own graphics engine is Lua-only, with optional support for LuaJITs FFI for acceleration. Works really nicely.
He gives a pretty good indirect argument _against_ using LuaJIT's FFI at 5:16 -- The FFI (even just C types, though giving access to most standard library functions also opens up its' own can of worms) actually open up a form of attack surface you normally wouldn't be able to achieve with Lua; for example, one could misuse a C pointer by manually setting the value to somewhere within the host binary's stack or heap and start messing around with the data, or even potentially call functions if they're in a vtable somewhere. Offhand, I recall a few cases of this in scripts for Morrowind's Script Extender, where the community hacked in Luajit support; I can't remember the exact name of the mod offhand, but there's one in particular that does some pretty gnarly manual pointer shenanigans to edit base game UI functions.
@@j.trades9691 While the problem you describe is real, even Lua code "sandboxed" in that way can often be exploited, especially if you allow loading bytecode(which helps loading times) - For me, and most games, that is a non-issue though: Only trusted Lua code is ever run. And you can get better sandboxing with LuaJIT if you desire: Just create a small FFI binding to the Lua C API, and create completely separate and isolated Lua_State(doesn't even have to be LuaJIT).
I think of LuaJIT as Lua 5.1 + optional C-like language. If you can't do it the Lua way, use the C way. If you can't do it the C way, do it the Lua way.
I'm curious about the &TypeName::fieldName syntax. What does that do?
It gives you the offset of the member from the base adress of the struct / class.
How to fix the compilers bugs of dev c++?
I have used kaguya library before fir lua in c++ and it is the best by far, it is header only and has much better api
How close is the community to convincing Javid to use vcpkg? 😁
28:10 well, technically you are giving it a pointer, not a reference
Wheres ep. 2?
luaJIT is even simpler, you declare function prototype in the lua Script and implement it in C and it will somehow work, i don't know how
btw, why don't you use luajit? It's supposed to be 'much faster' that plain lua. 🤔
Can you make an operating system like windows 😊
Is the same possible with Python ?
Yes, but I think it’s more complicated to include in your project.
better call sol
vimto
Hello,
Meh, just use C. ;)
lambda syntax is not very clear. simple as always is the best. explicit is better than implicit.
🤣 *Promosm*
*Embedding Lua in C++ with Sol: A Compare and Contrast*
This video compares and contrasts embedding Lua in C++ with and without the Sol library. Part 1 of the series covered a bare-bones implementation, while this video demonstrates Sol's advantages.
*Introduction and Setup (**0:00**)*
* This video is part 3 of a series on embedding Lua in C++.
* It showcases the Sol library as a superior alternative to the manual approach shown in Part 1.
* Sol simplifies Lua integration and offers various benefits, including safety features and reduced boilerplate code.
* The video uses the same Lua script and C++ code from Part 1 for comparison.
* Setting up Sol involves downloading the library and linking it to your project.
*Configuring the C++ Environment (**1:48**)*
* Sol streamlines configuration by handling Lua interaction through its interface.
* Sol allows explicit selection of Lua libraries to expose to the user, reducing the attack surface.
* Sol offers header-only inclusion for convenience.
*Running Lua Scripts (**3:46**)*
* Sol provides a `safe_script` function to execute Lua scripts with robust error handling and informative messages.
* This contrasts with the manual approach, which required custom error checking and stack manipulation.
*Reading Variables (**6:51**)*
* Sol's `get_or` function simplifies reading variables from Lua scripts with default values and type conversion.
* Sol also offers `optional` for checking variable existence without throwing exceptions.
* This approach is safer and more convenient than manually checking the Lua stack.
*Reading Tables (**11:14**)*
* Sol allows iterating through Lua tables using C++-style for loops and accessing key-value pairs.
* Sol objects can be easily converted to desired C++ types.
* Sol offers direct table indexing for accessing specific values.
*Calling Lua Functions from C++ (**15:03**)*
* Sol allows calling Lua functions directly with arguments and automatic return value handling.
* This eliminates the need for manual stack manipulation and error checking.
* Sol's `protected_function` provides additional safety by checking function validity before execution.
*Calling C++ Functions from Lua (**20:17**)*
* Sol enables injecting C++ functions into the Lua environment using lambdas.
* This simplifies the process compared to the manual approach of registering functions and managing the stack.
*Injecting Values and Functions into Lua (**22:35**)*
* Sol allows creating new Lua variables and functions directly from C++.
* The `script` function enables executing arbitrary Lua code within the C++ program.
*Mapping C++ Types to Lua (**23:58**)*
* Sol's `new_usertype` function facilitates mapping C++ structs to Lua objects with custom constructors and property access.
* This allows creating and manipulating C++ objects directly from Lua scripts.
*Using C++ Containers in Lua (**27:45**)*
* Sol provides bindings for standard C++ containers like vectors, allowing their use within Lua scripts.
* This enables populating and manipulating C++ containers directly from Lua.
*Conclusion (**30:15**)*
* Sol offers a powerful and intuitive way to embed Lua in C++ projects.
* Its features significantly reduce boilerplate code, improve safety, and enhance flexibility.
* The video encourages viewers to explore Sol and its capabilities further.
Disclaimer: i used gemini 1.5 pro to summarize the transcript
Token count 8,845 / 1,048,576
Summarize?? It basically returned a full transcript
@@desertfish74 The transcript has 6037 words, the summary 516.