Crate detect_newline_style 

detect-newline-style

Determine a string’s preferred newline character

Installation

cargo add detect-newline-style

Examples

use detect_newline_style::LineEnding;

fn main() {
    let text = "one\rtwo\r\nthree\nfour\n";
    let eol = LineEnding::find(text, LineEnding::Lf);

    assert_eq!(eol, LineEnding::Lf);

    let text = "one\rtwo\r\nthree\n";
    let eol = LineEnding::find_or_use_lf(text);

    assert_eq!(eol, LineEnding::Lf);

    let text = "one\rtwo\r\nthree\n";
    let eol = LineEnding::find_or_use_crlf(text);

    assert_eq!(eol, LineEnding::Crlf);

    assert_eq!(format!("{}", LineEnding::Cr), "\r");
    assert_eq!(format!("{}", LineEnding::Lf), "\n");
    assert_eq!(format!("{}", LineEnding::Crlf), "\r\n");
}

Migrations

0.x -> 1.x

Variant names now follow RFC 430

before	after
LineEnding::CR	LineEnding::Cr
LineEnding::LF	LineEnding::Lf
LineEnding::CRLF	LineEnding::Crlf

FromStr returns a concrete error type

LineEnding::from_str now fails with ParseLineEndingError instead of Box<dyn Error>. The old type was neither Send nor Sync, so the error could not cross a thread boundary or compose with most application error types.

Code that propagates with ? into a function returning Box<dyn Error> keeps working unchanged. Code that names the error type explicitly needs updating:

// before
let eol: Result<LineEnding, Box<dyn Error>> = LineEnding::from_str("\n");
// after
let eol: Result<LineEnding, ParseLineEndingError> = LineEnding::from_str("\n");

from_str also no longer lowercases its input. This has no observable effect, since the only valid inputs are "\r", "\n" and "\r\n".

LineEnding is now Copy

Existing code is unaffected - values that were previously moved are now copied.

The regex dependency is gone

This crate now has no dependencies at all. Behaviour is unchanged; see the tests covering "\r\r\n" and multi-byte input for the edge cases.

Structs

ParseLineEndingError

Returned by LineEnding::from_str when the input is not one of "\r", "\n" or "\r\n"

Enums

LineEnding

A newline style - see find to detect which style a given string prefers