|Maintainer||Brent Yorgey <email@example.com>|
Utilities for working with code blocks.
Given a block, if begins with a tag in square brackets, strip off
the tag and return a pair consisting of the tag and de-tagged
block. Otherwise, return
Nothing and the unchanged block.
Run the given function on the attributes and source code of code blocks with a tag matching the given tag (case insensitive). On any other blocks (which don't have a matching tag, or are not code blocks), run the other function.