use std::fmt;
pub struct Escape<'a>(pub &'a str);
impl<'a> fmt::Display for Escape<'a> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
let Escape(s) = *self;
let pile_o_bits = s;
let mut last = 0;
for (i, ch) in s.bytes().enumerate() {
match ch as char {
'"' | '\'' | '(' | ')' | '\\' => {
try!(fmt.write_str(&pile_o_bits[last..i]));
let s = match ch as char {
'"' => "\\\"",
'\'' => "\\\'",
')' => "\\)",
'(' => "\\(",
'\\' => "\\\\",
_ => unreachable!(),
};
try!(fmt.write_str(s));
last = i + 1;
}
_ => {}
}
}
if last < s.len() {
try!(fmt.write_str(&pile_o_bits[last..]));
}
Ok(())
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_fmt() {
assert_eq!("\\\"", format!("{}", Escape("\"")));
assert_eq!("\\\'", format!("{}", Escape("\'")));
assert_eq!("\\(", format!("{}", Escape("(")));
assert_eq!("\\)", format!("{}", Escape(")")));
assert_eq!("\\\\", format!("{}", Escape("\\")));
}
}