I think you could subclass some of the TAP modules. Subclass:

• TAP::Parser::Source to produce a stream from a code ref, and
• TAP::Parser to build the right sort of Source object when passed a code ref.
• TAP::Harness to build the right Parser object to build the right Source.

Ugh. This sort of thing that can too easily happen with OO inheritance. When it does, I always ask myself, "where did I go wrong?".

I hope I am missing some key parameter or callback that could be passed to TAP::Harness or TAP::Parser to avoid all the extra subclassing.