type- and router-based stack "combinators"

[Vaguery]

given the first-class nature of both Router and Recognizer items, consider a set of "peek" and "yank" combinators based on pattern-matching.

For example, :code-matching might peek/yank the first item matching a given Recognizer, by popping the top :code item and then pulling all other items routed to the same destination to the top (without routing, of course).