Official documentation for writing (procedural) macros

Where is the official documentation (up-to-date version) on writing procedural macros?

So far I have found:

However, in the second edition of the book, the chapter about the macros is missing and the reference says it is very incomplete.

I would like to write macros using the ecosystem of proc-macro2, but I am not sure where to find an official up-to-date guide.

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The book is there to cover the basics; the basics boil down to “use syn and quote.” Of course, doing more is more complex than that. We don’t have anyone with the experience and time to write such a thing, however, and so that’s what we’ve got.

But in the second edition, the chapter has the section about advanced features removed ( I know that the old version is still valid, but is probably outdated. What is supposed to replace Chap.19 of the book?

Note that says that the second edition has been removed, not that specific chapter.

Macros - The Rust Programming Language is the latest version of the book, and the section on the macro system.

My bad :frowning:. Thank you for clarifications

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No worries!

While it's not a documentation, if you want to get started with them, something like this worked for me:

  • First, try writing few ordinary macros, make sure they work well ‒ eg learn the tricks like using full paths to symbols, etc. There are docs for that out there.
  • Read the api docs of syn to get the feeling of the crate.
  • Find a procedural macro out there that does something similar to what you want to do and read through the real code.
  • Decide how your input and output should look like ‒ write the code that the macro should generate manually first.
  • Roll up your sleeves and dig in writing your own and don't give up ‒ and check the resulting code with cargo expand.