Purely functional code makes some things easier to understand: because values don't change, you can call functions and know that only their return value matters—they don't change anything outside themselves. But this makes many real-world applications difficult: how do you write to a database, or to the screen? In this screencast we look at one method for crossing this divide.
cargo gained a new feature this week! You can now download dependencies from alternative registries, alongside the dependencies you download from crates.io. This is an important step in enabling organizations to distribute their internal libraries through cargo without requiring them to upload those libraries to a public registry. This feature will be available on nightly only, and it is gated behind the alternative-registries feature gate. We’ve used feature gates to iterate on new and unstable features in rustc since the 1.
When you build real world applications, you are not always on the "happy path". You must deal with validation, logging, network and service errors, and other annoyances. How do you manage all this within a functional paradigm, when you can't use exceptions, or do early returns, and when you have no stateful data?