is a procedural Rust macro that stops compiling after a
user-specified deadline. It’s like TODO comments, but with
teeth. It’s probably best explained with an example:
It’s January 1, 2020. I’m working on some Rust code that compiles, but it’s not quite ready to ship.
I want to take a break, but I know myself – I’ll probably forget about the deficiency. I could add a TODO comment, but that depends on me actively searching for TODO comments next time I open the project.
To save me from myself, I add a quick todo macro with a deadline of January 2 (in ISO 8601 format):
// Implement the timeout handling todo!("2020-01-02")
That compiles for now, but as soon as the deadline is passed (i.e. our system clock returns Jan 3), builds start failing:
error: proc macro panicked --> src/main.rs:5:5 | 5 | todo!("2020-01-02"); | ^^^^^^^^^^^^^^^^^^^^ | = help: message: Tsk tsk. You missed your deadline.
todo-macro as a reminder that actively
forces your future self to deal with a problem.
Obviously, don’t use this in real projects unless you’re really comfortable with non-deterministic builds (I’m not). But still, wouldn’t it be nice to have a (safe) feature like this in your favourite IDE?