code and bitters

I've often wondered about the differences between lazy_static and once_cell, and starting with Rust 1.70 the standard library is also gaining the ability to create one-time-initialized values.

Most big projects end up using one of these crates, because lazy initialization is a very convenient way to implement almost-const global values that can't actually be const-initialized, because they need heap memory (e.g. String or Vec), read files or environment variables, or use types that don't have const initializers yet.

But how do they work? Let's spend some time looking at the differences between these three implementations.

The other day I made a joke on twitter, and learned some interesting things about raw pointers in Rust.

The abridged joke goes something like this:

Yosh: What do you mean Rust doesn't ship with rand built-in?

Me: ASLR to the rescue!

fn main() {
    let rand = main as usize;
    dbg!(rand);
}

I always forget the exact syntax to do shallow clones in git. I recently tracked it down for a few different use cases, so I thought I'd document them in one place since the documentation is kind of diffuse.

This project began the way many of my long Rust articles do-- I got curious about something. I started to wonder a few weeks ago about the relationship between crates that I download from crates.io, and the crate's upstream repository. Here are some of the questions I wanted to answer:

• How do I tell which git commit matches the published crate?
• Is there any guarantee that the published crate source matches the git source?
• What kinds of best practices exist? Is there room for improvement?

I recently became curious about the different tools that are available to do one specific thing in Rust: provide an implementation of the std::io::Write trait for an in-memory buffer.

This might be useful if you have serializable data that you want to store in a database, or if you want to add checksums or perform compression before storing or sending some data. It may also be useful for buffering ordinary network writes (though BufWriter might be easier).

How can this be done in Rust? What's the most efficient way of buffering serialized data?