lazy-static.rs VS anyhow

Normally lazy_static allows to have "const" code that cant be const https://github.com/rust-lang-nursery/lazy-static.rs

It's an additional crate, but you could try using lazy-static or once-cell and wrap the global value in a RwLock.

lazy_static : A macro for declaring lazily evaluated statics in Rust.

Without understanding the implementation details of lazy_static I figured it would be easier to benchmark it than to dig through its source code.

The templates need to be compiled before use, but this only needs to happen once. We can use lazy_static to ensure this compilation happens the first time the templates are accessed, and then reuse the compiled result for all subsequent access:

Now, the readme examples are tested like everything else.

https://github.com/rust-lang-nursery/lazy-static.rs/blob/mas...

Depending on your use case, thiserror and/or anyhow.

There is ? as well as the anyhow(https://github.com/dtolnay/anyhow) crate that deals with long nested result chains.

There are crates out there that help you reduce this boiler plate. thiserror is good for creating custom errors and color-eyre or anyhow are good for dynamic errors.

Give anyhow a look.

I've brought anyhow::Result into scope, making error handling super easy to use. We don't need to specify all our Error types. It can automatically convert any errors that implement std::error::Error, which should be all of them. If an error propagates all the way up to main(), we'll get all the info it's captured printed to stdout.

Alternatively, if you've got a lot of error types and you're outside a library (so directly in a binary where you don't plan to reuse code elsewhere) you can use anyhow. This gives you an error type you can basically propagate any other error through. On top of that you can attach context information at every return. It's basically a more complicated Result>.

One approach is to define a separate error type for each crate and then use anyhow, eyre or Box to wrap the error, whever a function can return errors originating in several different crates.

Have you tried anyhow and thiserror for making it as simple as .context("Message") or ? to type-convert and propagate errors up the call stack?