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fuchsia / third_party / rust / 994e712162af1d568a1751c32626478f2c613cc2
commit994e712162af1d568a1751c32626478f2c613cc2[log] [tgz]
authorMichal Nazarewicz <mina86@mina86.com>Mon Jan 16 17:56:01 2023 +0100
committerMichal Nazarewicz <mina86@mina86.com>Mon Jan 16 17:56:01 2023 +0100
tree24747f50907ee38bcd669df8bb6b3cd2b70dfd97
parent506052d49d3903ea554e4ce760cc53610cff4ef5 [diff]
Implement DoubleEnded and ExactSize for Take<Repeat> and Take<RepeatWith>

Repeat iterator always returns the same element and behaves the same way
backwards and forwards.  Take iterator can trivially implement backwards
iteration over Repeat inner iterator by simply doing forwards iteration.

DoubleEndedIterator is not currently implemented for Take<Repeat<T>>
because Repeat doesn’t implement ExactSizeIterator which is a required
bound on DEI implementation for Take.

Similarly, since Repeat is an infinite iterator which never stops, Take
can trivially know how many elements it’s going to return.  This allows
implementing ExactSizeIterator on Take<Repeat<T>>.

While at it, observe that ExactSizeIterator can also be implemented for
Take<RepeatWhile<F>> so add that implementation too.  Since in contrast
to Repeat, RepeatWhile doesn’t guarante to always return the same value,
DoubleEndedIterator isn’t implemented.

Those changes render core::iter::repeat_n somewhat redundant.

Issue: https://github.com/rust-lang/rust/issues/104434
Issue: https://github.com/rust-lang/rust/issues/104729
2 files changed
tree: 24747f50907ee38bcd669df8bb6b3cd2b70dfd97
  1. .github/
  2. compiler/
  3. library/
  4. LICENSES/
  5. src/
  6. tests/
  7. .clang-format
  8. .editorconfig
  9. .git-blame-ignore-revs
  10. .gitattributes
  11. .gitignore
  12. .gitmodules
  13. .ignore
  14. .mailmap
  15. Cargo.lock
  16. Cargo.toml
  17. CODE_OF_CONDUCT.md
  18. config.example.toml
  19. configure
  20. CONTRIBUTING.md
  21. COPYRIGHT
  22. INSTALL.md
  23. LICENSE-APACHE
  24. LICENSE-MIT
  25. README.md
  26. RELEASES.md
  27. REUSE.toml
  28. rust-bors.toml
  29. rustfmt.toml
  30. triagebot.toml
  31. x
  32. x.ps1
  33. x.py
README.md

Website | Getting started | Learn | Documentation | Contributing

This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.

Why Rust?

  • Performance: Fast and memory-efficient, suitable for critical services, embedded devices, and easily integrate with other languages.

  • Reliability: Our rich type system and ownership model ensure memory and thread safety, reducing bugs at compile-time.

  • Productivity: Comprehensive documentation, a compiler committed to providing great diagnostics, and advanced tooling including package manager and build tool (Cargo), auto-formatter (rustfmt), linter (Clippy) and editor support (rust-analyzer).

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Read “Installation” from The Book.

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