Feature request: re_take_until

[daboross]

This is a continuation of rust-bakery/nom#709, since regex nom functions have since moved into this crate.

I have a specific use case: I'd like to parse "[thing1, thing2part1,part2, thing3]" into ["thing1", "thing2part1,part2", "thing3"].

If I could guarantee no item-internal commas, I could implement this as:

delimited(
    tag("["),
    separated_list0(tag(", "), take_while(|c| ![',', ']'].contains(&c))),
    tag("]"),
)

However, since I want to parse a multi-letter sequence, this won't work.

I could do something with take_till, and probably will for this case, but I think that ends up pretty hacky.

On the other hand, regex engines are optimized for this kind of matching, so I believe using regex (or anything aho_corasick-based) is the best option.

I'd propose re_take_until, matching the interface of complete::take_until except taking in a regex rather than byte/string directly.

It'd be used like this to match the above pattern:

let closing_bracket_or_comma_space = regex::Regex::new(r"]|, ").unwrap();
delimited(
    tag("["),
    separated_list0(tag(", "), re_take_until(closing_bracket_or_comma_space),
    tag("]"),
)