pub fn loc_to_index(s: &str, line: usize, column: usize) -> Option<usize> {
let mut current = (1, 1);
for (idx, c) in s.char_indices() {
if current == (line, column) {
return Some(idx);
}
if c == '\n' {
current.0 += 1;
current.1 = 1;
} else {
current.1 += 1;
}
}
None
}