text={("!"|"\'" |"!"|"\""|"#" |"$" |"%"|"&"|"("|")"| "*"|"+"|","|"-"|"}"|"."|ASCII_ALPHANUMERIC)+}
chrs={SOI ~"chs"~ EOI}
field = { text? ~ (empty_entity | entity)* ~text? }
entity = { "<" ~ PUSH(ASCII_ALPHANUMERIC+) ~ ">" ~ field ~ "</" ~ POP ~ ">" }
empty_entity = { ("<" ~ PUSH(ASCII_ALPHANUMERIC+) ~ ">" ~ "</" ~ POP ~ ">") }
xml = {SOI ~(empty_entity| entity | "")~ EOI }
WHITESPACE = _{ " " | NEWLINE }