Looks much nicer!

Will reduce the user resistance to using Boost.Units - it's a bit verbose for mere engineers and scientist's taste ;-) But have you implemented it yet? (and are there any hidden gotchas? - the proposed C++ time literals suffixes proved to be a can of worms :-( Paul

I have a partial implementation for mass and length units. You can have a look at it : https://github.com/mkurdej/units/tree/feature/user-defined-literals You guess right, there are some problems to solve with output of quantities created with literals. See lines with FIXME in test/test_literals.cpp For those who were sceptic about "megagrams" and so on: that was just an example. Actually, I implemented tonnes (t), kilotonnes (kt), Gt and so on. Still, someone could possibly use Mg, Gg for uniformity... (but I haven't found such a person yet). Marek Kurdej -- Ph.D. candidate