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...K keep text out of match
\G anchor to previous match
\Z anchor to the end of the text before any trailing newlines
\O any character including newline
Capture groups and backreferences
\1 match first capture group
\2 match second capture group
\{N} match Nth capture group
(?<name> exp)
capture...
...Structured like match statement, the first matching
branch is the item that gets emitted.
match_cfg Documentation Minimum Supported Rust Version : 1.13.0. A convenience macro to ergonomically define an item depending on a large number of #[cfg] parameters. Structured like match statement, the first matching branch is the...
...Using match on Option
fn match_on_option(animal: &str) {
let text = "The black cat climbed the green tree";
match text.find(animal) {
Some(location) => println!("Location of {animal}: {location}"),
None => println!("None received - no {animal} found"),
};
}
Calling match_on_option("cat"); will print Location of cat: 10. Calling match...
...fn match_cmp(input) {
if let Ok(rule) = match_eq(input) { return rule; }
if let Ok(rule) = match_neq(input) { return rule; }
if let Ok(rule) = match_lt(input) { return rule; }
if let Ok(rule) = match_lte(input) { return rule; }
if let Ok(rule) = match_gt(input) { return rule; }
if...
featherweightmusings.blogspot.co.nz
...As I said earlier, if you want to match some `x` with type `&T` you can dereference once in the match clause or match the reference in every arm of the match expression. Example:
enum Enum1 { Var1, Var2, Var3}fn foo(x: &Enum1) { match *x { // Option 1: deref here. Var1...
Fuzzy Matching Library Fuzzy Matcher Fuzzy matching algorithm(s) in Rust! Usage In your Cargo.toml add the following: [dependencies] fuzzy-matcher = "*" Here are some code example: use fuzzy_matcher::FuzzyMatcher; use fuzzy_matcher::skim::SkimMatcherV2; let matcher = SkimMatcherV2::default(); assert_eq!(None, matcher.fuzzy_match("abc", "abx")); assert!(matcher...
...let val = (|(..):(_,_),(|__@_|__)|)((&*"\\",'🤔'),{})
Match
fn r#match() {
let val: () = match match match match match () {
() => ()
} {
() => ()
} {
() => ()
} {
() => ()
} {
() => ()
};
assert_eq!(val, ());
}
This is just matching nested match statements.
Match nested if
fn match_nested_if() {
let val = match () {
() if if if if true {true} else {false} {true} else {false} {true} else {false} => true,
_ => false...
...Which brings us to match. What is a match?// match is a list of patterns and what to do if they match.
//
// match EXPR {
// PAT => EXPR
// PAT => EXPR
// ..
// }
match (a, b) {
(5, x) => {
// if (a,b) matches (5,x), this block is executed
},
(x, 5) => {
// same thing: if (a,b...
## Summary
Allow attributes on match arms.
## Motivation
One sometimes wishes to annotate the arms of match statements with
attributes, for example with conditional compilation `#[cfg]`s or
with branch weights (the latter is the most important use).
For the conditional compilation, the work-around is duplicating the
whole containing function...
## Summary
[summary]: #summary
The current compiler implements a more expansive semantics for pattern
matching than was originally intended. This RFC introduces several
mechanisms to reign in these semantics without actually breaking
(much, if any) extant code:
- Introduce a feature-gated attribute `#[structural_match]` which can
be applied to a struct...
pub fn rmatch_indices<P>(&self, pat: P) -> RMatchIndices<'_, P>str::rmatch_indices — Returns an iterator over the disjoint matches of a pattern within self, yielded in reverse order along with the index of the match.
For matches of pat within self that overlap, only the indices corresponding to the last match are returned.
The pattern can be a &str...
Concise Control Flow with if let and let...else
The if let syntax lets you combine if and let into a less verbose way to handle values that match one pattern while ignoring the rest. Consider the program in Listing 6-6 that matches on an Option<u8> value in...
## Summary
[summary]: #summary
Extend Rust's pattern matching exhaustiveness checks to cover the integer types: `u8`, `u16`, `u32`, `u64`, `u128`, `usize`, `i8`, `i16`, `i32`, `i64`, `i128`, `isize` and `char`.
```rust
fn matcher_full(x: u8) {
match x { // ok
0 ..= 31 => { /* ... */ }
32 => { /* ... */ }
33 ..= 255 => { /* ... */ }
}
}
fn matcher_incomplete(x: u8) {
match x...
## Summary
[summary]: #summary
This RFC proposes to add a new kind of pattern, the **guard pattern.** Like match arm guards, guard patterns restrict another pattern to match only if an expression evaluates to `true`. The syntax for guard patterns, `pat if condition`, is compatible with match arm guard syntax, so...
...Whether a Pattern Might Fail to Match
Patterns come in two forms: refutable and irrefutable. Patterns that will match for any possible value passed are irrefutable. An example would be x in the statement let x = 5; because x matches anything and therefore cannot fail to match. Patterns that can...
## Table of contents
* [Summary][summary]
* [Motivation][motivation]
* [Detailed design][design]
* [Syntax][syntax]
* [Evolution][evolution]
* [Concrete syntax][concrete-syntax]
* [Expansion concerns][expansion-concerns]
* [Core API][core-api]
* [RegexBuilder][regexbuilder]
* [Replacer][replacer]
* [quote][quote]
* [RegexSet][regexset]
* [The `bytes` submodule][the-bytes-submodule]
* [Drawbacks][drawbacks]
* [Guaranteed linear time matching][guaranteed-linear-time-matching...
...let matches: Vec<_> = set.matches("foobar").into_iter().collect(); assert_eq!(matches, vec![0, 2, 3, 4, 6]); // You can also test whether a particular regex matched: let matches = set.matches("foobar"); assert!(!matches.matched(5)); assert!(matches.matched(6)); Usage: regex internals as a library The regex-automata directory...
Statically assert that a type matches another type assert_type_match A niche utility macro to statically assert that a type matches another type. Purpose The primary purpose of this crate is to make copying and pasting types from other crates into your own more future-proof by statically asserting...
hashtagIntroductionIn Haskell, pattern matching is mostly nice and easy. It might be made more complicated by strictness annotations (i.e. whether to evaluate sub-patterns lazily or strictly) or irrefutability annotations, but it doesn't have any special interactions with ownership, borrowing and mutability which are bread and butter of...
## Summary
[summary]: #summary
Various changes to the match ergonomics rules:
- On edition ≥ 2024, `&` and `&mut` patterns only remove a single layer of
references.
- On edition ≥ 2024, `mut` on an identifier pattern does not force its binding
mode to by-value.
- On all editions, `&` patterns can match against `&mut` references.
- On...