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Comment by nixpulvis | Hacker News Reader

I'm currently writing a shell in Rust, and have written a post about it. If you find this interesting you may also find my post interesting.

https://nixpulvis.com/ramblings/2018-10-15-building-a-shell-...

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Thanks for sharing, your posts are very well written.

I really like the idea of syntax highlighting before the user presses enter.

Any reason you are writing your own posix parser and readline implementation, rather than using existing Rust crates?

Partially to learn how, partially to maintain a consistent style, and partially to see where we can improve.

As for the POSIX parser specifically, I love grammars, and want to support multiple, and building one in LALRPOP is t too bad. Also I looked at conch-parser, but didn't want to use its AST, and decided to go this route.

I have been using the termion crate, and may have another PR to contribute. I have somewhat ambitious goals for the readline like library though.

As I was thinking about an improved user interface for the shell, it seemed like at some point you'd hit the limit of what is reasonable given the current split implementation between terminal emulator and shell. Do you think you'll get to a point where you'll need to build an all-in-one solution?

It's interesting you mention that. I'm (slightly) involved with the Alacritty project, and generally like the layer of abstraction here. If not only to support the existing status quo, but also as it leaves a lot of the platform specific features for the terminal.

ANSI, and the other standards are large and somewhat unwieldy though, and there are times it would be nice to do away with it all.

As for features, there's a number of things that you could argue for being implemented in either place. One feature I feel is a good fit for the shell for example is saving and being able to recall and/or pipe previous commands, while copy paste might be implemented in both.

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