cargo-xtask VS rand

💡 Inspired by matklad/cargo-xtask and based on 🏃‍♂️ Write your Rust project scripts in task.rs from the Rust ecosystem.

Using a cargo-xtask task to generate them as a manual step (inlyne currently does this)

As someone else said just is good for that job, or you could implement an xtask helper for these things and setup a suitable development environment with that: https://github.com/matklad/cargo-xtask/

Well tools like cornucopia, prisma-rust-client, protoc-gen-tonic, they don't generate in build.rs, but instead provide either a cli to be called ahead of time, or provide a library that can be called by your own binary (which should generally follow the xtask pattern)

If I understand, this is a tool for when working on the project itself? Akin to a helper script? You could go the cargo install route as already pointed out but there is also the xtask convention.

For simple cli apps for internal use, such as cargo-xtasks, I prefer pico_args due to its fast compile times.

For developer-oriented stuff, there's tools like xshell and cargo-xtask. For operator tasks that need to run in a deployed environment, it's not usually a big lift to add CLI subcommands to your binary. It's certainly more boilerplate and inertia than doing stuff in a live REPL, though, and sometimes difficult to recommend for truly one-off situations.

Making compatibility promises for distributions means they cannot take advantage of potential advancements in the field.

Defining an error type that is meaningful, portable, and compatible with no-std isn't straightforward. If the std lib's getrandom requires std, then just like that, rand and many other crates won't use it anyway. Using io::Result seems to me to face this challenge.

Some wasm targets can’t generate random numbers at all but in the case of the book because you are using wasm in a browser you can use JS to generate random numbers. I believe there’s a way to get the rand crate to use JS as the backend for generating rand but its a bit more convoluted than the easy one-liner that the book suggests.

rand

This uses rand and xcomplex to handle the mathematics, png to write image files, and dialoguer and indicatif for some pretty prompts and progress bars.

You can often achieve this without any unsafe by putting an assert!() on the length before the hot loop. For example, I got rid of some unsafe in rand that way.

This is a widely used method to map random integers to floating point numbers, but it has the disadvantage of wasting 1 bit of float mantissa precision.

On modern CPUs, its computational advantage over full-precision mapping methods, such as multiplication by a float, is not always clear [1].

[1] https://github.com/rust-random/rand/issues/416

In fact, there are a lot of crates in Rust where in other programming languages, it would be included in the standard library. Examples are regex, random number generators, additional iterator methods, macros for other collections, num traits, loggers, HTTP libraries, error handling, async runtimes, serialization and deserialization, date and time, and many more.