Function string

pub fn string(
    replacement: &str,
    append: impl FnMut(usize, &mut String),
    name_to_index: impl FnMut(&str) -> Option<usize>,
    dst: &mut String,
)

Available on crate feature alloc only.

Accepts a replacement string and interpolates capture references with their corresponding values.

append should be a function that appends the string value of a capture group at a particular index to the string given. If the capture group index is invalid, then nothing should be appended.

name_to_index should be a function that maps a capture group name to a capture group index. If the given name doesn’t exist, then None should be returned.

Finally, dst is where the final interpolated contents should be written. If replacement contains no capture group references, then dst will be equivalent to replacement.

See the module documentation for details about the format supported.

Example

use regex_automata::util::interpolate;

let mut dst = String::new();
interpolate::string(
    "foo $bar baz",
    |index, dst| {
        if index == 0 {
            dst.push_str("BAR");
        }
    },
    |name| {
        if name == "bar" {
            Some(0)
        } else {
            None
        }
    },
    &mut dst,
);
assert_eq!("foo BAR baz", dst);