using

Context managers for Carp. An experiment.

Installation

You can include using in your project like this:

(load "git@github.com:carpentry-org/using@0.0.2")

Usage

using relies on the interface close, which will take in a resource of some kind, clean it up, and return the result of the expression.

If that function is defined, you can do things like that:

(println*
  &(using (Result.unsafe-from-success (File.open "example")) f
    &(File.read-all &f)))

The file that was opened will be automatically closed once the scope is exited.

So, to reiterate: all you need to work with using is to have a function close that works on your type! It’s like manual borrow-checking for resource things! Nifty, eh?

And if you need to support multiple forms, using-do is your friend!

---

Have fun!