pico-args VS json

That's because the maintainer does not consider it an issue but an implementation detail: https://github.com/RazrFalcon/pico-args/issues/15

Maybe pico-args then?

If I forget to get around to it, would you mind poking RazrFalcon/pico-args about adding it to the comparison chart? I really like using that thing as something I can link people to with just a quick explanation of that particular trade-off.

If fewer dependencies is better, you can't get much fewer than pico-args, which has zero dependencies.

You might also want to check out pico-args, Gumdrop, and lexopt to see if any of them meet your needs.

For example, The Rust compiler isn't slow; we are. and pico-args: Alternatives.

For example, I'd love to go from StructOpt to Gumdrop for parsing command-line arguments and cut my compile times and output size by an order of magnitude, but Gumdrop uses String internally, which means it'll panic if it encounters a Windows path with un-paired surrogates or a mojibake'd posix path... some of which I actually have.

Oh wow. So serde_json doesn't roundtrip floats by default, it uses some imprecise faster algorithm https://github.com/serde-rs/json/issues/707

Good thing there's msgpack I guess.

tokio / hyper / toml / serde / serde_json / json5 / console

Serde JSON, an extension of the serde crate that enables the serialization and deserialization of Rust structs.

To serialize and deserialize data, we'll employ the popular serde crate along with serde_json. This will allow us to easily convert between Rust types and JSON when working with API requests and responses. For async operations we'll use the Rust futures crate.

From the Cargo.toml file above, we can see that the Perseus version at the time of publication is 0.4.2 and has the following dependencies that are common to both the engine side (server-side) and client side of a Perseus application: sycamore, serde, and serde_json.

serde_json

Number parsing uses a fairly naive but uses a lossless algorithm in musli-json. In serde_json they use a fork of lexical I haven't wrapped my head around. I wanted something simple to start with.

Your best best would be to use an enum. Either your own or something like the one from serde_json depending on what you are trying to do.

Don't do that if you care about memory usage. In your toy program, I wouldn't be surprised if memory usage was a lot better if you used Box instead. (even if it doesn't look like it, you can handle almost all the use cases of serde_json::Value with it, often not much less convenient)