I can't see where this has been proposed, so I will propose it. It is clear that programming languages vars/expressions will be required to carry units in addition to the value. A mission to Mars was botched because of units mismatch that was not caught. The languages F# and Fortress include a way to specify units on a variable and value. The compiler enforces unit conformance. I have no idea if automatic conversion is a good idea or not. I have no idea what the proper technical term I should have used; thus the use of furlongs in the subject to get attention. I don't know if this is difficult or not, but I am reasonable sure that compiler enforced units conformance will be required in government and space agency contracts. (Probably will happen a year after M$ has a good implementation available - this could be a competitive advantage). -Carlton Mills, Urbana, Illinois