Crate regexpr

Regular Expressions

This crate provides a Regex struct that compiles and tests regular expressions.

Example

use regexpr::Regex;

let regex = Regex::compile(r#"^a(.)c\1.*$"#).unwrap();
assert!(regex.test("abcb"));
assert!(regex.test("abcbde"));
assert!(!regex.test("bcdsd"));
assert!(!regex.test("abcd"));

Rules

Rule	Meaning
.	Matches any character
*	Matches the previous rule zero or more times
+	Matches the previous rule one or more times
?	Makes the previous rule optional
{n,m}	Matches the previous rule a minimun of n times and a maximun of m times1
[a-z]	Matches any character from a to z2
[agf]	Matches any of the characters inside
[^…]	Same as the rules above but negated
A | B	Maches A or B
(ABC)	Groups rules A B and C 3
\c	Escapes the character c4
\n OR \k<n>	Match the n’th capture group5

Greedy vs. Lazy

“Lazy” versions of * and + exist.
*? and +? work just as * and +, but they stop as soon as possible.

Example

    Regex: .*b
    Input: aaaaaabaaaaab
    Matches: One match "aaaaaabaaaaab"

    Regex: .*?b
    Input: aaaaaabaaaaab
    Matches: Two matches "aaaaaab" and "aaaaab"

---

1. If min or max are not present, it means there’s no limit on that size.
   Examples:
   {,12} matches a rule up to 12
   {3,} matches a rule at least 3 times.
   {,} is the same as * ↩

2. The ranges can be mixed.
   Examples:
   [a-z123]: Matches any character in the ranges a-z , 1, 2 or 3
   [^0-9ab]: Matches a character that IS NOT a number or a or b ↩

3. This captured groups can be later referenced ↩

4. Example: “\.” Matches a literal dot character. ↩

5. n must be an integer in the range [1,L] where L is the number of capture groups in the expression ↩

Structs

Regex

Main Regex struct

RegexConf

RegexError

RegexMatch

Represents a match of a string on a Regex

RegexMatcher

Iterator over all the matches of a string in a Regex

Traits

RegexTestable

This trait is used to add an extension method matches_regex to &str

ReplaceRegex