doc: suggest std::sync::LazyLock instead of once_cell::sync::Lazy

This seems fine now given that `LazyLock` has been stabilized for quite
some time.

Closes #1217, PR #1235

Author: noritada

CHANGELOG.md

@@ -1,3 +1,18 @@
+1.11.2 (2025-08-24)
+===================
+This is a new patch release of `regex` with some minor fixes.
+
+Improvements:
+
+* [BUG #1217](https://github.com/rust-lang/regex/issues/1217):
+Switch recommendation from `once_cell` to `std::sync::LazyLock`.
+
+Bug fixes:
+
+* [BUG #1281](https://github.com/rust-lang/regex/pull/1281):
+Remove `fuzz/` and `record/` directories from published crate on crates.io.
+
+
 1.11.1 (2024-10-24)
 ===================
 This is a new patch release of `regex` that fixes compilation on nightly

Cargo.toml

@@ -187,8 +187,6 @@ version = "0.8.5"
 default-features = false
 
 [dev-dependencies]
-# For examples.
-once_cell = "1.17.1"
 # For property based tests.
 quickcheck = { version = "1.0.3", default-features = false }
 # To check README's example

README.md

@@ -80,18 +80,19 @@ compilation itself expensive, but this also prevents optimizations that reuse
 allocations internally to the matching engines.
 
 In Rust, it can sometimes be a pain to pass regular expressions around if
-they're used from inside a helper function. Instead, we recommend using the
-[`once_cell`](https://crates.io/crates/once_cell) crate to ensure that
-regular expressions are compiled exactly once. For example:
+they're used from inside a helper function. Instead, we recommend using
+[`std::sync::LazyLock`], or the [`once_cell`] crate,
+if you can't use the standard library.
+
+This example shows how to use `std::sync::LazyLock`:
 
 ```rust
-use {
-    once_cell::sync::Lazy,
-    regex::Regex,
-};
+use std::sync::LazyLock;
+
+use regex::Regex;
 
 fn some_helper_function(haystack: &str) -> bool {
-    static RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"...").unwrap());
+    static RE: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"...").unwrap());
     RE.is_match(haystack)
 }
 
@@ -104,6 +105,9 @@ fn main() {
 Specifically, in this example, the regex will be compiled when it is used for
 the first time. On subsequent uses, it will reuse the previous compilation.
 
+[`std::sync::LazyLock`]: https://doc.rust-lang.org/std/sync/struct.LazyLock.html
+[`once_cell`]: https://crates.io/crates/once_cell
+
 ### Usage: match regular expressions on `&[u8]`
 
 The main API of this crate (`regex::Regex`) requires the caller to pass a

src/lib.rs

@@ -471,23 +471,20 @@ to a few **milliseconds** depending on the size of the pattern.) Not only is
 compilation itself expensive, but this also prevents optimizations that reuse
 allocations internally to the regex engine.
 
-In Rust, it can sometimes be a pain to pass regexes around if they're used from
-inside a helper function. Instead, we recommend using crates like [`once_cell`]
-and [`lazy_static`] to ensure that patterns are compiled exactly once.
+In Rust, it can sometimes be a pain to pass regular expressions around if
+they're used from inside a helper function. Instead, we recommend using
+[`std::sync::LazyLock`], or the [`once_cell`] crate,
+if you can't use the standard library.
 
-[`once_cell`]: https://crates.io/crates/once_cell
-[`lazy_static`]: https://crates.io/crates/lazy_static
-
-This example shows how to use `once_cell`:
+This example shows how to use `std::sync::LazyLock`:
 
 ```rust
-use {
-    once_cell::sync::Lazy,
-    regex::Regex,
-};
+use std::sync::LazyLock;
+
+use regex::Regex;
 
 fn some_helper_function(haystack: &str) -> bool {
-    static RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"...").unwrap());
+    static RE: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"...").unwrap());
     RE.is_match(haystack)
 }
 
@@ -501,6 +498,9 @@ Specifically, in this example, the regex will be compiled when it is used for
 the first time. On subsequent uses, it will reuse the previously built `Regex`.
 Notice how one can define the `Regex` locally to a specific function.
 
+[`std::sync::LazyLock`]: https://doc.rust-lang.org/std/sync/struct.LazyLock.html
+[`once_cell`]: https://crates.io/crates/once_cell
+
 ### Sharing a regex across threads can result in contention
 
 While a single `Regex` can be freely used from multiple threads simultaneously,