Maybe this is a version of William Harrison's DebugT monad with rollback, listed in his periodic table of effects?
http://www.cs.missouri.edu/~harrisonwl/Presentations/UIUCFM05.ppt I've never seen a definition of the monad itself... http://www.haskell.org/pipermail/beginners/2010-January/003371.html _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
