A Rust macro that stops compiling after a user-specified deadline. Like TODO comments with teeth.
This is just a dumb (but fun) toy, don't use it in a real project unless you're really comfortable with non-deterministic builds.
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 as a reminder that actively forces your future self to deal with a problem.
TODO for todo-macro
It would be cool if users didn't even have to specify a date. Like maybe they call
todo_in_x_days!(3) and that magically stops compiling after 3 days. This might be doable with some extremely hacky local state, but I'd definitely go to compiler hell for that.
I wonder whether
todo could function like Scala's
??? (not implemented) expression, so it replaces entire expressions instead of being used like a statement.
Try+document macro expansion using
cargo expand as per this workshop
You'll need to add
#![feature(proc_macro_hygiene)] to your code that uses
todo, at least until this Rust issue is sorted out.