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Flattening Rust’s learning curve

(corrode.dev)
451 points birdculture | 2 comments | 13 May 25 22:25 UTC | HN request time: 0s | source
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Waterluvian ◴[14 May 25 00:35 UTC] No.43979472[source]▶
Write a CHIP8 emulator!

Bonus: do it with no heap allocation. This actually makes it easier because you basically don’t deal with lifetimes. You just have a state object that you pass to your input system, then your guest cpu system, then your renderer, and repeat.

And I mean… look just how incredibly well a match expression works for opcode handling: https://github.com/ablakey/chip8/blob/15ce094a1d9de314862abb...

My second (and final) rust project was a gameboy emulator that basically worked the same way.

But one of the best things about learning by writing an emulator is that there’s enough repetition you begin looking for abstractions and learn about macros and such, all out of self discovery and necessity.

replies(1): >>43980773 #
namuol ◴[14 May 25 04:21 UTC] No.43980773[source]▶
I’ve found emulators to be a pretty poor first project for rust specifically for the reasons you alluded to: That you need to know to write it without heap allocation (or other hoop jumping so long as you avoid juggling lifetimes) when so much literature and example emulator code doesn’t do this is a recipe for a bad experience. Ask me how I know.

If you’re going to write an emulator in this style, why even use an imperative language when something like Haskell is designed for this sort of thing?

replies(1): >>43983405 #
1. Waterluvian ◴[14 May 25 11:55 UTC] No.43983405[source]▶
These emulators already exist in basically every language, so why do anything? The point is the journey, which doesn’t need to be the shortest, most optimal path possible.
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2. namuol ◴[14 May 25 15:29 UTC] No.43985722[source]▶
I’m saying it’s not optimal for learning the language, not that it’s not worth doing. I’ve worked on 3 different emulators for fun over the last few years, my first in rust. It was a bad experience for learning rust because I was following prior art which relied heavily on shared data structures and lots of poking randomly at blocks of RAM, a very natural way to think when you’re engrossed in the mechanics of an 8-bit CPU.

I had a better time writing a raycaster and later a path tracer, although by then I had learned to avoid dealing with the borrow checker…