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A comment on Tokio Console. Parent comment

Re:Tokio Console by sam0x17 on Friday December 17, 2021 @01:58PM (#29596698)
Have you delved at all into the potential for having a true "rust repl"? This is something I have very much wanted for some time, where instead of just recompiling and re-running everything every time, it just compiles the new line and executes it in the memory context of the already running rust program. I'm just not enough of a low level rust hacker to get it working, but imagine the web frameworks and things that could exist with a good REPL for rapid debugging and prototyping in rust.

I actually spent a whole summer trying to do this in Crystal and I was very nearly successful, however a few low level limitations got in my way at the end of the day. In Crystal it is actually possible to do this kind of REPL if you have a perfect ability to deep marshal/copy any object, and I almost, almost got that working here: https://github.com/sam0x17/marshal

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Re:Tokio Console by epage on Friday December 17, 2021 @08:13PM (#29600431)
I think a low effort, high value step in the usability direction of a REPL is cargo-script

I've written some on it [0] and there was a recent reddit thread discussing it [1]

[0] https://epage.github.io/blog/2021/09/learning-rust/

[1] https://www.reddit.com/r/rust/comments/rddokp/media_most_up_...

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Re:Tokio Console by mycoliza on Friday December 17, 2021 @02:45PM (#29597403)
Something like that would definitely be useful! It's not really in scope for this project, which is intended as a telemetry and diagnostics tool, but I can imagine a Rust REPL being useful. Of course, in order to do that, you'd need to implement a general-purpose Rust interpreter, which seems like a fairly large amount of work.

In practice, I personally just use REPLs mostly for quick testing out of a small expression or something...and honestly, I usually just use the Rust playground (https://play.rust-lang.org/) for this. Small examples are compiled fast enough in the playground that it's kind of a REPL-like experience for testing stuff out semi-interactively...but it's not the same as connecting to a running application and running new code inside of that application. That's something that seems very difficult to add to Rust, a compiled, statically-linked language with limited support for hot reloading...

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Re:Tokio Console by carreau on Friday December 17, 2021 @04:21PM (#29598503)
There is https://github.com/google/evcxr/blob/main/evcxr_repl/README....
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