Chapter 19.5 Macros links to “The Little Book of Rust Macros” which hasn't been updated since 2016

[verhovsky]

I read that Little Book before looking up its source code and seeing that it hasn't been updated in a long time https://github.com/DanielKeep/tlborm/commits/master

It seems to have some outdated information now DanielKeep/tlborm#19 so I'm not sure it's a good idea to link to it from the official Rust book unless it's forked and updated, on the other hand it was very helpful and approachable.

[carols10cents]

This is the best for now until as you say, either that book gets updated or someone creates a new book. I'd rather link to something rather than nothing. Thanks though!