Capture groups?

[vedantroy]

Is there an elegant way to capture a small snippet in a rule without having to create an entire new rule? Example:

foo_bar = { "\\baz{" ~ ASCII_ALPHANUMERIC+ ~ "}" ~ ("\r" | "\n") }

I want to grab whatever is represented by ASCII_ALPHANUMERIC+ without creating a whole new rule.

[CAD97]

Unfortunately no, the unit of capture is the rule.