Hello guys!
tl;dr: Please review the code of my bootcamp demo project 
Its description is at rx-observer/README.md at main · dmgorsky/rx-observer · GitHub
Ukrainian Rust Community ([1]) approx. twice a year holds Rust Bootcamp ([2]) /based on Rust-incubator ([3])/.
After mastering the theory (concepts, basics, idioms, etc.) and practice (e.g. building web backends), participants have to come up with a test project demonstrating gained skills, and have 1 week to implement it and get a feedback.
My capstone project uses proc-macro to decorate variables and use them, besides the main program, in specific context that can either hold a snapshot of our vars state, or a history of their changes. Instead of rewriting a program in NewTypes, I tried to use macro inspired by trace-var ([4]).
The description is in README at rx-observer/README.md at main · dmgorsky/rx-observer · GitHub
Usage examples are in examples folder.
Your PR code review and feedback is appreciated!
[1] Ukrainian Rust Community (Ukrainian Rust Community | LinkedIn)
[2] Ukrainian Rustcamp (GitHub - rust-lang-ua/rustcamp: Getting ready for prod)
[3] Rust-incubator (GitHub - instrumentisto/rust-incubator: Learning Rust step-by-step.)
[4] trace-var (syn/examples/trace-var at master · dtolnay/syn · GitHub)