fn main() { const PGRM : &str = "fn main() { const PGRM : &str = \"%s\"; println!(\"{}\", PGRM.replacen(\"%s\", &PGRM.escape_default().to_string(), 1)); }"; println!("{}", PGRM.replacen("%s", &PGRM.escape_default().to_string(), 1)); }