macro_rules! character_set {
() => {{
[false; 256]
}};
($value:literal $(,$rest:literal)*) => {{
const A: &[u8] = $value;
let mut a = character_set!($($rest),*);
let mut i = 0;
while i < A.len() {
a[A[i] as usize] = true;
i += 1;
}
a
}}
}
pub(crate) use character_set;