Module show_notes::e009

Composing a Rustic tune

• Date: 2016-01-09
• Subject: Getting into the nitty-gritty with Rust’s traits.
• Audio

Notes

Last time, we looked at generics and traits at a high level. This time, we dig deeper on traits, looking specifically at std::iter::Iterator as an example of a powerful trait that can be composed across types, and then at how we might compose multiple traits on a single type.

We also talk about the syntax for traits, the use of marker traits, some of the things you can’t presently do with traits, and even just a smidge about the future of traits in Rust. All that in less than 20 minutes!

You’ll find today’s source example fairly interesting, I think: it’s just one type, but it uses almost every concept discussed on the show today!

Links

• Nick Cameron: “Thoughts on Rust in 2016”
• “Upcoming breakage starting in Rust 1.7, from RFCs 1214 and 136”
  • RFC 1214: Clarify (and improve) rules for projections and well-formedness
  • RFC 136: Ban private items in public APIs
• The Rust Book:
  • Traits
  • Trait objects (dynamic dispatch)
• The Rust reference:
  • std::iter and std::iter::Iterator
  • Add
  • Drop
  • PartialEq and Eq
  • PartialOrd and Ord
  • Special traits
  • Trait objects
• RFC: impl specialization
  • Aaron Turon: “Specialize to reuse”

Sponsors

• Aleksey Pirogov
• Chris Palmer
• Derek Morr
• Hamza Sheikh
• Luca Schmid
• Micael Bergeron
• Ralph Giles (“rillian”)
• reddraggone9
• William Roe

Become a sponsor

• Patreon
• Venmo
• Dwolla
• Cash.me

Follow

• New Rustacean:
  • Twitter: @newrustacean
    • App.net: @newrustacean
  • Email: hello@newrustacean.com
• Chris Krycho
  • Twitter: @chriskrycho
    • App.net: @chriskrycho

Structs

• DoubleAndOne
  Define a simple struct on which to implement Iterator… and more!

Traits

• ASimpleTrait
  Define a simple trait so we can see how it works.

Functions

• demonstrate_for
  Demonstrate using a for loop over an (infinite!) iterator.