Trait regex::Replacer

source ·

pub trait Replacer {
    fn replace_append(&mut self, caps: &Captures<'_>, dst: &mut String);

    fn no_expansion<'r>(&'r mut self) -> Option<Cow<'r, str>> { ... }
    fn by_ref<'r>(&'r mut self) -> ReplacerRef<'r, Self> { ... }
}

Expand description

Replacer describes types that can be used to replace matches in a string.

In general, users of this crate shouldn’t need to implement this trait, since implementations are already provided for &str and FnMut(&Captures) -> String (or any FnMut(&Captures) -> T where T: AsRef<str>), which covers most use cases.

Required Methods

source

fn replace_append(&mut self, caps: &Captures<'_>, dst: &mut String)

Appends text to dst to replace the current match.

The current match is represented by caps, which is guaranteed to have a match at capture group 0.

For example, a no-op replacement would be dst.extend(caps.get(0).unwrap().as_str()).

Provided Methods

source

fn no_expansion<'r>(&'r mut self) -> Option<Cow<'r, str>>

Return a fixed unchanging replacement string.

When doing replacements, if access to Captures is not needed (e.g., the replacement byte string does not need $ expansion), then it can be beneficial to avoid finding sub-captures.

In general, this is called once for every call to replacen.

source

fn by_ref<'r>(&'r mut self) -> ReplacerRef<'r, Self>

Return a Replacer that borrows and wraps this Replacer.

This is useful when you want to take a generic Replacer (which might not be cloneable) and use it without consuming it, so it can be used more than once.

Example

use regex::{Regex, Replacer};

fn replace_all_twice<R: Replacer>(
    re: Regex,
    src: &str,
    mut rep: R,
) -> String {
    let dst = re.replace_all(src, rep.by_ref());
    let dst = re.replace_all(&dst, rep.by_ref());
    dst.into_owned()
}