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Comment by eigenrick | Hacker News Reader

This demonstrates the brilliance of Rust's syntax extensions. Not only is the code more readable and ergonomic, but also type safe.

Errors or mismatches in implementations are caught at compile time, saving minutes (or potentially hours or days) in frustrating debugging.

Nice work! This looks fantastic.

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> This demonstrates the brilliance of Rust's syntax extensions.

Sadly this functionality currently requires nightly or using a code generating build script via syntex :(

(Rocket currently only works with nightly, but someone could pretty easily add a syntex port since the APIs are the same)

With macros 1.1, some of this functionality is available on stable, but not the functionality needed by this. I don't know if we plan a "macros 1.2" that stabilizes tokentree expansion for all decorators (not just type item decorators). ("Macros 2.0" is the final polished version of Rust procedural and regular macros, for which there are concrete plans but it will take time to get to)

For those not watching the compiler development traffic, macros 1.1 (which will enable things like #[derive(FromForm))]) could land in stable as soon as 6 weeks from now. We haven't really started thinking about a "macros 1.2" yet, so syntex will still have some use.

If you want to know more about our glorious macros 1.1 future, David Tolnay just have a great meetup talk all about this a few weeks ago:

https://air.mozilla.org/rust-meetup-december-2016-12-15/

The plan is for macros 1.1 to land in the next release, I wrote about it yesterday: https://news.ycombinator.com/item?id=13239774

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