Function is_single

std/re/src/main/matcher.rs:263–265

(node: &Node)

}

fn is_single(node: &Node) -> bool {
    matches!(node, Node::Char(_) | Node::AnyChar | Node::Class { .. })
}

fn is_word(c: char) -> bool {
    c.is_alphanumeric() || c == '_'