Struct onig::Regex

pub struct Regex { /* private fields */ }

This struct is a wrapper around an Oniguruma regular expression pointer. This represents a compiled regex which can be used in search and match operations.

Implementations

impl Regex

pub fn captures<'t>(&self, text: &'t str) -> Option<Captures<'t>>

Returns the capture groups corresponding to the leftmost-first match in text. Capture group 0 always corresponds to the entire match. If no match is found, then None is returned.

pub fn find_iter<'r, 't>(&'r self, text: &'t str) -> FindMatches<'r, 't>

Returns an iterator for each successive non-overlapping match in text, returning the start and end byte indices with respect to text.

Example

Find the start and end location of every word with exactly 13 characters:

let text = "Retroactively relinquishing remunerations is reprehensible.";
for pos in Regex::new(r"\b\w{13}\b").unwrap().find_iter(text) {
    println!("{:?}", pos);
}
// Output:
// (0, 13)
// (14, 27)
// (28, 41)
// (45, 58)

pub fn captures_iter<'r, 't>(&'r self, text: &'t str) -> FindCaptures<'r, 't>

Returns an iterator over all the non-overlapping capture groups matched in text. This is operationally the same as find_iter (except it yields information about submatches).

Example

We can use this to find all movie titles and their release years in some text, where the movie is formatted like “‘Title’ (xxxx)”:

let re = Regex::new(r"'([^']+)'\s+\((\d{4})\)")
               .unwrap();
let text = "'Citizen Kane' (1941), 'The Wizard of Oz' (1939), 'M' (1931).";
for caps in re.captures_iter(text) {
    println!("Movie: {:?}, Released: {:?}", caps.at(1), caps.at(2));
}
// Output:
// Movie: Citizen Kane, Released: 1941
// Movie: The Wizard of Oz, Released: 1939
// Movie: M, Released: 1931

pub fn split<'r, 't>(&'r self, text: &'t str) -> RegexSplits<'r, 't>

Returns an iterator of substrings of text delimited by a match of the regular expression. Namely, each element of the iterator corresponds to text that isn’t matched by the regular expression.

This method will not copy the text given.

Example

To split a string delimited by arbitrary amounts of spaces or tabs:

let re = Regex::new(r"[ \t]+").unwrap();
let fields: Vec<&str> = re.split("a b \t  c\td    e").collect();
assert_eq!(fields, vec!("a", "b", "c", "d", "e"));

pub fn splitn<'r, 't>( &'r self, text: &'t str, limit: usize ) -> RegexSplitsN<'r, 't>

Returns an iterator of at most limit substrings of text delimited by a match of the regular expression. (A limit of 0 will return no substrings.) Namely, each element of the iterator corresponds to text that isn’t matched by the regular expression. The remainder of the string that is not split will be the last element in the iterator.

This method will not copy the text given.

Example

Get the first two words in some text:

let re = Regex::new(r"\W+").unwrap();
let fields: Vec<&str> = re.splitn("Hey! How are you?", 3).collect();
assert_eq!(fields, vec!("Hey", "How", "are you?"));

pub fn scan_with_region<F>( &self, to_search: &str, region: &mut Region, options: SearchOptions, callback: F ) -> i32

where F: Fn(i32, i32, &Region) -> bool,

Scan the given slice, capturing into the given region and executing a callback for each match.

pub fn scan<'t, CB>(&self, to_search: &'t str, callback: CB)

where CB: Fn(i32, Captures<'t>) -> bool,

Scan a Pattern and Observe Captures

The scan function takes a haystack to_search and invokes the given callback for each capture of this expression.

impl Regex

pub fn capture_names_len(&self) -> usize

Returns the number of named groups into regex.

pub fn foreach_name<F>(&self, callback: F) -> i32

where F: FnMut(&str, &[u32]) -> bool,

Calls callback for each named group in the regex. Each callback gets the group name and group indices.

impl Regex

pub fn replace<R: Replacer>(&self, text: &str, rep: R) -> String

Replaces the leftmost-first match with the replacement provided. The replacement can be a regular string or a function that takes the matches Captures and returns the replaced string.

If no match is found, then a copy of the string is returned unchanged.

Examples

Note that this function is polymorphic with respect to the replacement. In typical usage, this can just be a normal string:

let re = Regex::new("[^01]+").unwrap();
assert_eq!(re.replace("1078910", ""), "1010");

But anything satisfying the Replacer trait will work. For example, a closure of type |&Captures| -> String provides direct access to the captures corresponding to a match. This allows one to access submatches easily:

let re = Regex::new(r"([^,\s]+),\s+(\S+)").unwrap();
let result = re.replace("Springsteen, Bruce", |caps: &Captures| {
    format!("{} {}", caps.at(2).unwrap_or(""), caps.at(1).unwrap_or(""))
});
assert_eq!(result, "Bruce Springsteen");

pub fn replace_all<R: Replacer>(&self, text: &str, rep: R) -> String

Replaces all non-overlapping matches in text with the replacement provided. This is the same as calling replacen with limit set to 0.

See the documentation for replace for details on how to access submatches in the replacement string.

pub fn replacen<R: Replacer>(&self, text: &str, limit: usize, rep: R) -> String

Replaces at most limit non-overlapping matches in text with the replacement provided. If limit is 0, then all non-overlapping matches are replaced.

See the documentation for replace for details on how to access submatches in the replacement string.

impl Regex

pub fn new(pattern: &str) -> Result<Self, Error>

Create a Regex

Simple regular expression constructor. Compiles a new regular expression with the default options using the ruby syntax. Once compiled, it can be used repeatedly to search in a string. If an invalid expression is given, then an error is returned.

Arguments

• pattern - The regex pattern to compile

Examples

use onig::Regex;
let r = Regex::new(r#"hello (\w+)"#);
assert!(r.is_ok());

pub fn with_encoding<T>(pattern: T) -> Result<Regex, Error>

where T: EncodedChars,

Create a Regex, Specifying an Encoding

Attempts to compile pattern into a new Regex instance. Instead of assuming UTF-8 as the encoding scheme the encoding is inferred from the pattern buffer.

Arguments

• pattern - The regex pattern to compile

Examples

use onig::{Regex, EncodedBytes};
let utf8 = Regex::with_encoding("hello");
assert!(utf8.is_ok());
let ascii = Regex::with_encoding(EncodedBytes::ascii(b"world"));
assert!(ascii.is_ok());

pub fn with_options( pattern: &str, option: RegexOptions, syntax: &Syntax ) -> Result<Regex, Error>

Create a new Regex

Attempts to compile a pattern into a new Regex instance. Once compiled, it can be used repeatedly to search in a string. If an invalid expression is given, then an error is returned. See onig_sys::onig_new for more information.

Arguments

• pattern - The regex pattern to compile.
• options - The regex compilation options.
• syntax - The syntax which the regex is written in.

Examples

use onig::{Regex, Syntax, RegexOptions};
let r = Regex::with_options("hello.*world",
                            RegexOptions::REGEX_OPTION_NONE,
                            Syntax::default());
assert!(r.is_ok());

pub fn with_options_and_encoding<T>( pattern: T, option: RegexOptions, syntax: &Syntax ) -> Result<Self, Error>

where T: EncodedChars,

Create a new Regex, Specifying Options and Ecoding

Attempts to comile the given pattern into a new Regex instance. Instead of assuming UTF-8 as the encoding scheme the encoding is inferred from the pattern buffer. If the regex fails to compile the returned Error value from onig_new contains more information.

Arguments

• pattern - The regex pattern to compile.
• options - The regex compilation options.
• syntax - The syntax which the regex is written in.

Examples

use onig::{Regex, Syntax, EncodedBytes, RegexOptions};
let pattern = EncodedBytes::ascii(b"hello");
let r = Regex::with_options_and_encoding(pattern,
                                         RegexOptions::REGEX_OPTION_SINGLELINE,
                                         Syntax::default());
assert!(r.is_ok());

pub fn match_with_options( &self, str: &str, at: usize, options: SearchOptions, region: Option<&mut Region> ) -> Option<usize>

Match String

Try to match the regex against the given string slice, starting at a given offset. This method works the same way as match_with_encoding, but the encoding is always utf-8.

For more information see Match vs Search

Arguments

• str - The string slice to match against.
• at - The byte index in the passed slice to start matching
• options - The regex match options.
• region - The region for return group match range info

Returns

Some(len) if the regex matched, with len being the number of bytes matched. None if the regex doesn’t match.

Examples

use onig::{Regex, SearchOptions};

let r = Regex::new(".*").unwrap();
let res = r.match_with_options("hello", 0, SearchOptions::SEARCH_OPTION_NONE, None);
assert!(res.is_some()); // it matches
assert!(res.unwrap() == 5); // 5 characters matched

pub fn match_with_encoding<T>( &self, chars: T, at: usize, options: SearchOptions, region: Option<&mut Region> ) -> Option<usize>

where T: EncodedChars,

Match String with Encoding

Match the regex against a string. This method will start at the offset at into the string and try and match the regex. If the regex matches then the return value is the number of characters which matched. If the regex doesn’t match the return is None.

For more information see Match vs Search

The contents of chars must have the same encoding that was used to construct the regex.

Arguments

• chars - The buffer to match against.
• at - The byte index in the passed buffer to start matching
• options - The regex match options.
• region - The region for return group match range info

Returns

Some(len) if the regex matched, with len being the number of bytes matched. None if the regex doesn’t match.

Examples

use onig::{Regex, EncodedBytes, SearchOptions};

let r = Regex::with_encoding(EncodedBytes::ascii(b".*")).unwrap();
let res = r.match_with_encoding(EncodedBytes::ascii(b"world"),
                                0, SearchOptions::SEARCH_OPTION_NONE, None);
assert!(res.is_some()); // it matches
assert!(res.unwrap() == 5); // 5 characters matched

pub fn match_with_param<T>( &self, chars: T, at: usize, options: SearchOptions, region: Option<&mut Region>, match_param: MatchParam ) -> Result<Option<usize>, Error>

where T: EncodedChars,

Match string with encoding and match param

Match the regex against a string. This method will start at the offset at into the string and try and match the regex. If the regex matches then the return value is the number of characters which matched. If the regex doesn’t match the return is None.

For more information see Match vs Search

The contents of chars must have the same encoding that was used to construct the regex.

Arguments

• chars - The buffer to match against.
• at - The byte index in the passed buffer to start matching
• options - The regex match options.
• region - The region for return group match range info
• match_param - The match parameters

Returns

Ok(Some(len)) if the regex matched, with len being the number of bytes matched. Ok(None) if the regex doesn’t match. Err with an Error if an error occurred (e.g. retry-limit-in-match exceeded).

Examples

use onig::{Regex, EncodedBytes, MatchParam, SearchOptions};

let r = Regex::with_encoding(EncodedBytes::ascii(b".*")).unwrap();
let res = r.match_with_param(EncodedBytes::ascii(b"world"),
                             0, SearchOptions::SEARCH_OPTION_NONE,
                             None, MatchParam::default());
assert!(res.is_ok()); // matching did not error
assert!(res.unwrap() == Some(5)); // 5 characters matched

pub fn search_with_options( &self, str: &str, from: usize, to: usize, options: SearchOptions, region: Option<&mut Region> ) -> Option<usize>

Search pattern in string

Search for matches the regex in a string. This method will return the index of the first match of the regex within the string, if there is one. If from is less than to, then search is performed in forward order, otherwise – in backward order.

For more information see Match vs Search

Arguments

• str - The string to search in.
• from - The byte index in the passed slice to start search
• to - The byte index in the passed slice to finish search
• options - The options for the search.
• region - The region for return group match range info

Returns

Some(pos) if the regex matches, where pos is the byte-position of the start of the match. None if the regex doesn’t match anywhere in str.

Examples

use onig::{Regex, SearchOptions};

let r = Regex::new("l{1,2}").unwrap();
let res = r.search_with_options("hello", 0, 5, SearchOptions::SEARCH_OPTION_NONE, None);
assert!(res.is_some()); // it matches
assert!(res.unwrap() == 2); // match starts at character 3

pub fn search_with_encoding<T>( &self, chars: T, from: usize, to: usize, options: SearchOptions, region: Option<&mut Region> ) -> Option<usize>

where T: EncodedChars,

Search for a Pattern in a String with an Encoding

Search for matches the regex in a string. This method will return the index of the first match of the regex within the string, if there is one. If from is less than to, then search is performed in forward order, otherwise – in backward order.

For more information see Match vs Search

The encoding of the buffer passed to search in must match the encoding of the regex.

Arguments

• chars - The character buffer to search in.
• from - The byte index in the passed slice to start search
• to - The byte index in the passed slice to finish search
• options - The options for the search.
• region - The region for return group match range info

Returns

Some(pos) if the regex matches, where pos is the byte-position of the start of the match. None if the regex doesn’t match anywhere in chars.

Examples

use onig::{Regex, EncodedBytes, SearchOptions};

let r = Regex::with_encoding(EncodedBytes::ascii(b"l{1,2}")).unwrap();
let res = r.search_with_encoding(EncodedBytes::ascii(b"hello"),
                                 0, 5, SearchOptions::SEARCH_OPTION_NONE, None);
assert!(res.is_some()); // it matches
assert!(res.unwrap() == 2); // match starts at character 3

pub fn search_with_param<T>( &self, chars: T, from: usize, to: usize, options: SearchOptions, region: Option<&mut Region>, match_param: MatchParam ) -> Result<Option<usize>, Error>

where T: EncodedChars,

Search pattern in string with encoding and match param

Search for matches the regex in a string. This method will return the index of the first match of the regex within the string, if there is one. If from is less than to, then search is performed in forward order, otherwise – in backward order.

For more information see Match vs Search

The encoding of the buffer passed to search in must match the encoding of the regex.

Arguments

• chars - The character buffer to search in.
• from - The byte index in the passed slice to start search
• to - The byte index in the passed slice to finish search
• options - The options for the search.
• region - The region for return group match range info
• match_param - The match parameters

Returns

Ok(Some(pos)) if the regex matches, where pos is the byte-position of the start of the match. Ok(None) if the regex doesn’t match anywhere in chars. Err with an Error if an error occurred (e.g. retry-limit-in-match exceeded).

Examples

use onig::{Regex, EncodedBytes, MatchParam, SearchOptions};

let r = Regex::with_encoding(EncodedBytes::ascii(b"l{1,2}")).unwrap();
let res = r.search_with_param(EncodedBytes::ascii(b"hello"),
                              0, 5, SearchOptions::SEARCH_OPTION_NONE,
                              None, MatchParam::default());
assert!(res.is_ok()); // matching did not error
assert!(res.unwrap() == Some(2)); // match starts at character 3

pub fn is_match(&self, text: &str) -> bool

Returns true if and only if the regex matches the string given.

For more information see Match vs Search

Arguments

• text - The string slice to test against the pattern.

Returns

true if the pattern matches the whole of text, false otherwise.

pub fn find(&self, text: &str) -> Option<(usize, usize)>

Find a Match in a Buffer, With Encoding

Finds the first match of the regular expression within the buffer.

Note that this should only be used if you want to discover the position of the match within a string. Testing if a pattern matches the whole string is faster if you use is_match. For more information see Match vs Search

Arguments

• text - The text to search in.

Returns

The offset of the start and end of the first match. If no match exists None is returned.

pub fn find_with_encoding<T>(&self, text: T) -> Option<(usize, usize)>

where T: EncodedChars,

Find a Match in a Buffer, With Encoding

Finds the first match of the regular expression within the buffer.

For more information see Match vs Search

Arguments

• text - The text to search in.

Returns

The offset of the start and end of the first match. If no match exists None is returned.

pub fn encoding(&self) -> OnigEncoding

Get the Encoding of the Regex

Returns

Returns a reference to an oniguruma encoding which was used when this regex was created.

pub fn captures_len(&self) -> usize

Get the Number of Capture Groups in this Pattern

pub fn capture_histories_len(&self) -> usize

Get the Size of the Capture Histories for this Pattern

Trait Implementations

impl Debug for Regex

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for Regex

fn drop(&mut self)

Executes the destructor for this type.

impl PartialEq for Regex

fn eq(&self, other: &Regex) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Regex

impl Send for Regex

impl StructuralPartialEq for Regex

impl Sync for Regex