Struct regex_automata::hybrid::regex::Config

pub struct Config { /* private fields */ }

The configuration used for compiling a hybrid NFA/DFA regex.

A regex configuration is a simple data object that is typically used with Builder::configure.

Implementations

impl Config

pub fn new() -> Config

Return a new default regex compiler configuration.

pub fn utf8(self, yes: bool) -> Config

Whether to enable UTF-8 mode or not.

When UTF-8 mode is enabled (the default) and an empty match is seen, the iterators on Regex will always start the next search at the next UTF-8 encoded codepoint when searching valid UTF-8. When UTF-8 mode is disabled, such searches are begun at the next byte offset.

If this mode is enabled and invalid UTF-8 is given to search, then behavior is unspecified.

Generally speaking, one should enable this when SyntaxConfig::utf8 and thompson::Config::utf8 are enabled, and disable it otherwise.

Example

This example demonstrates the differences between when this option is enabled and disabled. The differences only arise when the regex can return matches of length zero.

In this first snippet, we show the results when UTF-8 mode is disabled.

use regex_automata::{hybrid::regex::Regex, MultiMatch};

let re = Regex::builder()
    .configure(Regex::config().utf8(false))
    .build(r"")?;
let mut cache = re.create_cache();

let haystack = "a☃z".as_bytes();
let mut it = re.find_leftmost_iter(&mut cache, haystack);
assert_eq!(Some(MultiMatch::must(0, 0, 0)), it.next());
assert_eq!(Some(MultiMatch::must(0, 1, 1)), it.next());
assert_eq!(Some(MultiMatch::must(0, 2, 2)), it.next());
assert_eq!(Some(MultiMatch::must(0, 3, 3)), it.next());
assert_eq!(Some(MultiMatch::must(0, 4, 4)), it.next());
assert_eq!(Some(MultiMatch::must(0, 5, 5)), it.next());
assert_eq!(None, it.next());

And in this snippet, we execute the same search on the same haystack, but with UTF-8 mode enabled. Notice that byte offsets that would otherwise split the encoding of ☃ are not returned.

use regex_automata::{hybrid::regex::Regex, MultiMatch};

let re = Regex::builder()
    .configure(Regex::config().utf8(true))
    .build(r"")?;
let mut cache = re.create_cache();

let haystack = "a☃z".as_bytes();
let mut it = re.find_leftmost_iter(&mut cache, haystack);
assert_eq!(Some(MultiMatch::must(0, 0, 0)), it.next());
assert_eq!(Some(MultiMatch::must(0, 1, 1)), it.next());
assert_eq!(Some(MultiMatch::must(0, 4, 4)), it.next());
assert_eq!(Some(MultiMatch::must(0, 5, 5)), it.next());
assert_eq!(None, it.next());

pub fn get_utf8(&self) -> bool

Returns true if and only if this configuration has UTF-8 mode enabled.

When UTF-8 mode is enabled and an empty match is seen, the iterators on Regex will always start the next search at the next UTF-8 encoded codepoint. When UTF-8 mode is disabled, such searches are begun at the next byte offset.

Trait Implementations

impl Clone for Config

fn clone(&self) -> Config

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Config

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

Formats the value using the given formatter.

impl Default for Config

fn default() -> Config

Returns the “default value” for a type.

impl Copy for Config