6
Where is the sort method implemented on Vec? (A surprisingly informative question to answer if you're learning rust) (lemmy.ml)
submitted 3 months ago* (last edited 3 months ago) by maegul@lemmy.ml to c/learningrustandlemmy@lemmy.ml
0 comments fedilink hide all child comments

You've gotta be familiar with Traits to try to work this out.

Just in case you want to try to work it out your self firstGotta say, after hearing that rust is not an OOP/Class-inheritance language, and is strongly and explicitly typed, the Deref trait feels like a helluva drug!

Obviously it's not the same thing, but working this out definitely had me making a couple of double takes.

Somewhat awkwardly, I worked it out through the standard lib docs before reading ch 15 of the book (it's more fun this way!).

And for those who want a quick answer:

  • Read the Deref docs, especially the deref coercion part
  • This allows a variable of a particular type to be implicitly substituted with another variable of a different type.
  • It happens any time a reference is passed in/out of a function, including self in method calls.
    • And obviously requires that Deref be implemented.
  • So sort() isn't implemented on Vec, it's implemented on the slice type ([T]).
  • But Vec implements Deref, substituting [T] for Vec<T> in all function/method calls.
  • Which means Vec gets all of the methods implemented on [T] ... almost like Vec is a subclass of [T]!
  • And yea, OOP people want to abuse this (see, eg, rust-unofficial on anti-patterns)
no comments (yet)
sorted by: hot top controversial new old
there doesn't seem to be anything here
this post was submitted on 02 Jul 2024
6 points (100.0% liked)

Learning Rust and Lemmy

231 readers
2 users here now

Welcome

A collaborative space for people to work together on learning Rust, learning about the Lemmy code base, discussing whatever confusions or difficulties we're having in these endeavours, and solving problems, including, hopefully, some contributions back to the Lemmy code base.

Rules TL;DR: Be nice, constructive, and focus on learning and working together on understanding Rust and Lemmy.

Running Projects

Policies and Purposes

  1. This is a place to learn and work together.
  2. Questions and curiosity is welcome and encouraged.
  3. This isn't a technical support community. Those with technical knowledge and experienced aren't obliged to help, though such is very welcome. This is closer to a library of study groups than stackoverflow. Though, forming a repository of useful information would be a good side effect.
  4. This isn't an issue tracker for Lemmy (or Rust) or a place for suggestions. Instead, it's where the nature of an issue, what possible solutions might exist and how they could be or were implemented can be discussed, or, where the means by which a particular suggestion could be implemented is discussed.

See also:

Rules

  1. Lemmy.ml rule 2 applies strongly: "Be respectful, even when disagreeing. Everyone should feel welcome" (see Dessalines's post). This is a constructive space.
  2. Don't demean, intimidate or do anything that isn't constructive and encouraging to anyone trying to learn or understand. People should feel free to ask questions, be curious, and fill their gaps knowledge and understanding.
  3. Posts and comments should be (more or less) within scope (on which see Policies and Purposes above).
  4. See the Lemmy Code of Conduct
  5. Where applicable, rules should be interpreted in light of the Policies and Purposes.

Relevant links and Related Communities

Thumbnail and banner generated by ChatGPT.

founded 8 months ago
MODERATORS
maegul@lemmy.ml
sorrybookbroke@sh.itjust.works
Jayjader@jlai.lu