My Struggles with Rust

Post by djhworld » Sun, May 07, 2017, 2:02 PM UTC

burntsushi wrote: post #36

djhworld wrote: post #34

The author doesn't really justify why he needed to port the python script to rust in the first place. Pulling down some JSON, doing a bit of transformation and sending alerts seems like a perfect candidate for a high level language, I don't see any reason why you would port it to Rust unless you had significant performance concerns

> The author doesn't really justify why he needed to port the python script to rust in the first place. And they don't need to. When I first learned Rust, I tried to write a `filter` function. Why would I ever do that? I could write `filter` much easier in Python, or heck, just use the `filter` method on iterators that is already in the standard library. I did it because I saw it as an opportunity to learn. I wanted…

Post by vfclists » Sun, May 07, 2017, 2:06 PM UTC

Symmetry wrote: post #17

vfclists wrote: post #12

Use Nim

The author was using this as an opportunity to learn Rust so while it might look sort of crazy to use a systems programming language for build failure notification there was a reason behind their decision. Nim is a lovely language but in the author's case he doesn't really care about speed for the use case so if they were being strictly pragmatic they could have just stuck with Python.

Post by chillingeffect » Sun, May 07, 2017, 2:08 PM UTC

tinco wrote: post #5

Being able to port a 20 line Python script to a 20 line Rust is the holy grail. Surely Rust has the ambition to one day achieve that, but it is by no means the main priority nor the original design goal of the language. Justin criticizes the file_double function, it being complex with nested maps and conditionals. All of this complexity is also in the Python code, just hidden away in abstractions, the library and the…

Post by eriknstr » Sun, May 07, 2017, 2:09 PM UTC

erickt wrote: post #31

Hello Justin Turpin! Sorry to hear your struggles with rust. It's always going to be a bit more verbose using rust than Python due to type information, but I think there are some things we could do to simplify your code. Would you be comfortable posting the 20 line code for us to review? I didn't see a link in your post. Anyway, so some things that could make your script easier: * for simple scripts I tend to use the…

Post by eriknstr » Sun, May 07, 2017, 2:14 PM UTC

Pxtl wrote: post #58

QuercusMax wrote: post #48

Earlier quoted context omitted.

Was the expect method​ supposed to be named except, as in exception? That would make a lot more sense.

Not a Rust guy, but it looks like a way to say "this option value is required and if it is not present, crash with the following error". So "expect" is a fair name, since it means a value is expected and the absence of a value is unexpected. I could see "required" or "require" as a better name. Or even just break the "positive names" rule and go with "notOptional".

    let mut file = File::open("conf.json")
        .expect("could not open file");

    let config: Value = serde::from_reader(file)
        .expect("config has invalid json");

    let jenkins_server = config.get("jenkins_server")
        .expect("jenkins_server key not in config")
        .as_str()
        .expect("jenkins_server key is not a string");

    let mut file = File::open("conf.json")
        .expect("Need to be able to open file `conf.json'.");

    let config: Value = serde::from_reader(file)
        .expect("The file `conf.json' must contain valid JSON.");

    let jenkins_server = config.get("jenkins_server")
        .expect("The config must have a key named `jenkins_server'.")
        .as_str()
        .expect("The config value of `jenkins_server' must be a string.");