clap-rs VS bevy

We will be using the library for Clap - A simple-to-use, efficient, and full-featured library for parsing command line arguments and subcommands.

I recently came across this question (and associated answer) on the clap repository. The answer given is a good one. But I wanted to expand with my own findings and practices, which spurred the motivation for this post.

We can also use tuple-like struct syntax and named-field struct syntax for enum variants within our enum; this is because unlike in other OOP languages, Rust enums are actually sum types. You can read more about how powerful Rust enums are in another article we wrote here. You can have optional arguments by simply wrapping the types in Option, but if you want to add a flag to a command you can use bool, since clap recognises that flags are either there or not there. Let's have a look at what this might look like:

I began by developing a wrapper for the CurseForge API, which turned out to be a lengthy and challenging process but constituted the bulk of the work. Next, I coded the CLI, which was relatively straightforward. Instead of using the clap crate, a Rust tool for generating CLIs, I opted for the following line of code:

By this time I had already gotten tired of parsing arguments by myself and had looked for something to help with that. I found a really dang good argument parsing library called clap. What makes it so cool is it's largely declarative for common uses. You simply mark up a struct with attributes, and the parser automatically generates the usage and all the argument parsing code.

How CLI arguments are handled (using clap).

Is this just referring to wrapping based on the terminal width? That is supported with the wrap_help feature though I have been considering making it a default feature.

CLI, use Clap. If you want to get fancy, use Tui.

As our CLI is getting more complex, we'll use the clap crate to parse the command line arguments.

Bevy. A very young engine where you need to write the game entirely in Rust—that was appealing. But fatal flaws overshadowed everything: no editor, the engine brutally enforces the ECS approach, and the game's architecture must literally bend to fit this paradigm. So, you won't migrate to another engine at all—you just throw away all the code and start from scratch.

Missing one of the best choices as long as "maturity" isn't on the top of your list: Bevy - https://bevyengine.org/

Game engine written in Rust, leveraging ECS in almost every place and way, with a really capable WASM export option. Wrestling ECS for the first time might take you some time, but in my experience helps you keep game code as clean and decoupled as game code could be.

I don't see WASM/WebGPU changing anything when it comes to gaming, as an industry, personally. 3d visualizations and interactive websites? Yeah definitely a nice improvement over WebGL 2, if years late.

WebGPU is pretty far behind what AAA games are using even as of 6 years ago. There's extra overhead and security in the WebGPU spec that AAA games do not want. Browsers do not lend themselves to downloading 300gb of assets.

Additionally, indie devs aren't using Steam for the technical capabilities. It's purely about marketshare. Video games are a highly saturated market. The users are all on Steam, getting their recommendations from Steam, and buying games in Steam sales. Hence all the indie developers publish to Steam. I don't see a web browser being appealing as a platform, because there's no way for developers to advertise to users.

That's also only indie games. AAA games use their own launchers, because they don't _need_ the discoverability from being on Steam. So they don't, and avoid the fees. If anything users _want_ the Steam monopoly, because they like the platform, and hate the walled garden launchers from AAA companies.

(I work on high end rendering features for the Bevy game engine https://bevyengine.org, and have extensive experience with WebGPU)

I was working through an example in the repo for the Bevy game engine recently and came across this code

That's possible. I did spend quite a bit of time tinkering with compiler flags, and followed the recommendations.

Some notes I found just now seems to agree with my results, though: https://github.com/bevyengine/bevy/issues/3978#issuecomment-...

I cannot recommend immediate mode GUI programming based on the limitations I've experienced working with egui.

egui does not support putting two widgets in the center of the screen: https://github.com/emilk/egui/issues/3211

It's really easy to get started with immediate mode, it's really easy to bust out some UI, but the second you start trying to involve dynamically resized context and responsive layouts -- abandon all hope. The fact it has to calculate everything in a single pass makes these things hard/impossible.

... that said, I'm still using it for https://ant.care/ (https://github.com/MeoMix/symbiants) because it's the best thing I've found. I'm crossing my fingers that Bevy's UI story (or Kayak https://github.com/StarArawn/kayak_ui) become significantly more fleshed out sooner rather than later. Bevy 0.13 should have lots more in this area though (https://github.com/bevyengine/bevy/discussions/9538)

I've also been enjoying building My First Game™ in Bevy using ECS. The community around Bevy really shines, but Flecs (https://github.com/SanderMertens/flecs) is arguably a more mature, open-source ECS implementation. You don't get to write in Rust, though, which makes it less cool in my book :)

I'm not very proud of the code I've written because I've found writing a game to be much more confusing than building websites + backends, but, as the author notes, it certainly feels more elegant than OOP or globals given the context.

I'm building for WASM and Bevy's parallelism isn't supported in that context (yet? https://github.com/bevyengine/bevy/issues/4078), so the performance wins are just so-so. Sharing a thread with UI rendering suuucks.

If anyone wants to browse some code or ask questions, feel free! https://github.com/MeoMix/symbiants

These days, some game engines have done pretty well at making compute shaders easy to use (such as Bevy [1] -- disclaimer, I contribute to that engine). But telling the scientific/financial/etc. community that they need to run their code inside a game engine to get a decent experience is a hard sell. It's not a great situation compared to how easy it is on NVIDIA's stack.

[1]: https://github.com/bevyengine/bevy/blob/main/examples/shader...

This is the API you need: https://github.com/bevyengine/bevy/pull/9774