Condensed borrowing from Arguments

arg.rs

// From https://github.com/Neo-Type/manifest/blob/35bcff0ee504b7a8007bd01cf455554bb4fa51aa/src/main.rs#L56
lazy_static! {
    // Regular expression to strip invalid file name characters.
    static ref INVALID_FILE_CHARAS: Regex = Regex::new("[^A-Za-z0-9._-]").unwrap();
}
fn main() {
  // `clap` library is used to parse arguments
  // The details are not relevant to our discussion
  let args = make_parser().get_matches();

  // ...

  // Let's get a vector of borrowed strings from the parsed command line arguments
  let images: Vec<&str> = args.values_of("image").unwrap().collect();
  let images: Vec<Images> = images.into_iter().map(|s| parse_image(s)).collect();
  
  // ??? 
  // Profit?
}

/// Parse a Docker image name into an `Image` struct
pub fn parse_image<'a>(image: &'a str) -> Image<'a> {
    // The `docker_image::parse` function does not allocate memory
    let image_parts = docker_image::parse(image);
    Image {
        image: image,
        repository: image_parts.repository,
        tag: image_parts.tag.unwrap_or_else(|| "latest"),
        tarball: Cow::from(format!(
            "images/{}.tar.gz",
            INVALID_FILE_CHARAS.replace_all(image, "_")
        )),
    }
}