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// Copyright 2014-2017 The html5ever Project Developers. See the
// COPYRIGHT file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::fmt;
pub fn to_escaped_string<T: fmt::Debug>(x: &T) -> String {
// FIXME: don't allocate twice
let string = format!("{:?}", x);
string.chars().flat_map(|c| c.escape_default()).collect()
}
/// If `c` is an ASCII letter, return the corresponding lowercase
/// letter, otherwise None.
pub fn lower_ascii_letter(c: char) -> Option<char> {
match c {
'a'..='z' => Some(c),
'A'..='Z' => Some((c as u8 - b'A' + b'a') as char),
_ => None,
}
}
#[cfg(test)]
#[allow(non_snake_case)]
mod test {
use super::lower_ascii_letter;
use mac::test_eq;
test_eq!(lower_letter_a_is_a, lower_ascii_letter('a'), Some('a'));
test_eq!(lower_letter_A_is_a, lower_ascii_letter('A'), Some('a'));
test_eq!(lower_letter_symbol_is_None, lower_ascii_letter('!'), None);
test_eq!(
lower_letter_nonascii_is_None,
lower_ascii_letter('\u{a66e}'),
None
);
}
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