tail VS aoc-runner-derive

I'm working on a side-quest, and I just started using unit tests (hurray!): https://github.com/LeCyberDucky/tail/blob/main/src/main.rs

Since the program takes over the terminal when running, my trusty old debugging method of adding print statements everywhere doesn't work all too well here. Therefore, I took on the side quest of creating my own version of the UNIX tool "tail" this weekend. I'll write my debugging statements to a file instead and then use this tool to monitor that file. There are ways to achieve this without writing my own tool, but I wasn't completely satisfied with the stuff I tried (I'm on Windows), so I thought it would be fun and hopefully be too big a detour to implement it myself.

I've been using those today in this small project: https://github.com/LeCyberDucky/tail/blob/main/src/main.rs

I don't think that a way do this is actually guaranteed to work, see Crate local state for procedural macros? Issue #44034. That said there are crates that do this anyway since currently rustc expands macros from top to bottom in source files and doesn't cache the result so the proc macros are always re-run each time the code is compiled. Two crates that rely on this by using global variables in their procedural macro code are: enum_dispatch and aoc-runner (see here).