OK This has become a big feud, apologies for choosing the incorrect words and being rude. Let me put it another way by "disciplined mutation" all i meant was lo

OK This has become a big feud, apologies for choosing the incorrect words and being rude. Let me put it another way by "disciplined mutation" all i meant was localised mutation. A lexically scoped local variable is enough to handle the spread of mutation, i dont see the need for a specific datatype to handle mutations exclusively. Monads make mutations explicit and global. I hope that makes sense.