Gregory Ewing writes: > A bit more on SMFs, and then some I/O. > > http://www.cosc.canterbury.ac.nz/greg.ewing/essays/monads/DemystifyingMonads2.html Thanks. It would be good to spell out SMF at the start of the page. "The definition of / above" (__truediv__ method) was not given "above" (in the definition of SMF).