Parser:String Transform:Regex Capture

[bbappserver]

Instead of substituting regex, I sometimes also want to just get a capture group when parsing. This could go in string matcher or string converter, but the idea is I don't just want to filter, I want to filter and grab a specific subset.

[roachcord3]

Would also be useful for situations where you really want a variable length lookbehind assertion. Prevents the pattern from ballooning into a huge chain of |s. It's be great if Hydrus just generally had logic for saying "give me this specific (probably named) group of the matched regex" whenever it lets you put in a regex.