fix clone regression

test bench::bench_derive_clone ... bench:     454,318 ns/iter (+/- 11,401)
test bench::bench_match_clone  ... bench:     183,570 ns/iter (+/- 10,652)
test bench::bench_new_clone    ... bench:     177,907 ns/iter (+/- 2,234)
1 file changed
tree: 2af42097c91d6e81bf2017795b9081b6cd1d44a9
  1. .github/
  2. src/
  3. tests/
  4. .gitignore
  5. bors.toml
  6. Cargo.toml
  7. LICENSE-APACHE
  8. LICENSE-MIT
  9. README.md
README.md

smol_str

CI Crates.io API reference

A SmolStr is a string type that has the following properties:

  • size_of::<SmolStr>() == 24 (therefore == size_of::<String>() on 64 bit platforms)
  • Clone is O(1)
  • Strings are stack-allocated if they are:
    • Up to 23 bytes long
    • Longer than 23 bytes, but substrings of WS (see src/lib.rs). Such strings consist solely of consecutive newlines, followed by consecutive spaces
  • If a string does not satisfy the aforementioned conditions, it is heap-allocated
  • Additionally, a SmolStr can be explicitly created from a &'static str without allocation

Unlike String, however, SmolStr is immutable. The primary use case for SmolStr is a good enough default storage for tokens of typical programming languages. Strings consisting of a series of newlines, followed by a series of whitespace are a typical pattern in computer programs because of indentation. Note that a specialized interner might be a better solution for some use cases.

MSRV Policy

Minimal Supported Rust Version: latest stable.

Bumping MSRV is not considered a semver-breaking change.