Believe me, a script language with static type, generic type, gc support, and good speed, a little meta programming, that’s a diamond so many game programmers want to own.
If nim could be an host language for develop game engine, and embed itself as script, it would be a killer on this area.
The only one can do this work well as far as I know: C#. But still too large, too complicated for history compatibility, too old.
I’m tired for switch between different language as game programmers.
In my experience nimscript is not the best option where speed matters. The fastest option would likely be a dynamic library.
My personal preference is wasm though, which is also pretty fast. Nim compiles nicely to wasm with clang, and you can do hot code reloading as much as you like.
If your project is cross-platform in the sense of being native or a web-app, you could do several scripting backends and run the same nim code as wasm for web or as a dll for native targets. But I'm just using wasm for both.
The hardest part is to define the ABI. On the lowest level it should be just plain c functions with only basic types and int handles (instead of pointers), because you can't share memory between wasm and host like you can do with a dll.
know a little bit about wasm，the speed can be accepted for most of case, thanks for tell me, I have a choice at least now.
Still waiting for the dynamic library solution. I keep dig into docs to see what can I do.
If currently nim don’t support this, I am afraid I have to leave nim.
I think you're misunderstanding a bit what Nim is. The "normal" way to run Nim is to compile it, whether that is into its own binary or if it's into a dynamic library to be loaded by another program doesn't matter much. When compiled Nim is about on par speed-wise with C.
So yes, Nim can absolutely be used as a language compiled into dynamic library form and embedded into a game. That being said you can also write the entire game in Nim, and load plugins written in Nim (or another language).
If you want to have scripts that users can write themselves and run within your program without having to compile anything then NimScript might be interesting. It's slower than compiled Nim, but about on par with Python (although Python uses a lot of C libraries underneath the hood and NimScript has gotten a tad slower IIRC). You can implement the heavy lifting parts in compiled Nim and then only use NimScript to call the heavier functions and it might be fast enough for what you want to do.
So if I understand your question correctly then Nim is a great option, small stand-alone binaries (or dynamic libraries) that you can use pretty much however you want.
Thanks so much for the reply, it helps a lot.
Currently, I want to use nim as script language in unity engine which the host lang is C#.
From the experience I involve with Lua, I have to find a way to compile nim system into a dynamic library.
In Lua, it will export a function like: loadscript to make loading script in host language to be possible. And it also export some functions to communicate data between host and lua.
So, my first question is: how do I compile the nim system into a c like dynamic library(windows) .Such thing always full with details, we always have to follow a sample code or project which come from official documentation or expert that I am not yet found.
If above done, then: May I have a function like (loadscript) to use? Or I just need to pass a script dir path to nim?
Last when above done: how do I communicate with nim now? It call a function that pass pointer? Or like Lua it create a arg stack to exchange data between Lua and host?
And I have to say I have found some interesting or power thing that the other script language lack of. And maybe that’s why you say I misunderstood something.
That is: I can actually compile all nim script into native form like a dynamic library.SUCH A POWER! It has a native machine code speed now.
I don’t need a loadscript function now. I don’t realize this because no one other script language can offer such thing. And for C# or C++ or rust, they are such huge thing that you can’t deploy a compiler of them with game.
I think this can be done on pc. But I am not a compiler/lang expert, I don’t know if it is possible on a mobile platform?
Am I right?
But it lost the meaning of script language. You can’t take the on flying advantage in development anymore.
I understand the question more clearly.
I don't need compile nim sysytem in to dynamic library(still be cool and powerful anyway), I just using nim compile the all script in to c like dynamic library, and publish the library to game binary archive, and load it just using host lang.
From the point of publishing, nim is a script lang in this situation.
Why I make things so complicated? Because you can't republish the whole host game app in android or ios easily for the reason of business and limitation of platform.
I am sure this can be done well in pc and android platform. But it seems that apple mobile ios forbidden such thing. If I am not lucky, I have to fallback to the first solution I ask before.
Thanks. It seems what I want.
It seems about nimscript and nim. But not nim itself as script lang. But could be a starting.
I don't really understand what you're looking for. If you want to use a native language to create extensions, there are two main options: either WASM or the C ABI. You can compile the extension as a dynamic library and use it with C#, but that would be pretty terrible. It would require you to compile the library for every platform or ship the compiler along with it. WASM is less troublesome: you can compile the extension once and use it everywhere, without needing to ship the compiler. The downside is that WASM doesn't support shared memory*.
What I said applies to basically every native language out there, not just Nim. Anyway, I'd rather stick with a language designed to be embedded, with a good C API, like Lua.
From another side, you can think about it: why C# become only script lang supported for unity now. Unity used to support three scirpt lang: JS, a python-like lang(forgot name), C#. And it turns out the most of developers choose C# be the best among them in these years.
For anyone are not family with relations between them: Unity c++ core layer -> c# script lang layer -> lua/ILRumtime/other.
Just compile a dynlib and call it from C# using FFI (https://learn.microsoft.com/en-us/dotnet/standard/native-interop/pinvoke).
Nim code should be something like this:
proc sum(a: int, b: int): int {.cdecl, dynlib, exportc.} =
a + bUsing nim c --app:lib .\src\main.nim to compile. And you can use it from any other language with FFI, like luajit:
local ffi = require 'ffi'
ffi.cdef [[
int sum(int, int);
]]
local lib = ffi.load('main.dll')
print(lib.sum(2, 2))