Native Python support for units?

It seems to me that units are not a property of a variable, but of a number. Perhaps that is more pythonic - or more amenable to duck typing (if a value walks and talks like a length... it's a length). Python already has the ability not to add incompatible types at run time (like a variable representing a string to a variable representing an integer). So if you were using numbers with types, it would be just as pythonic to fail to add 5 metres to 30 seconds.

Interestingly you can *multiply* or *divide* distance and time, giving a quantity with a complex unit - speed might be 5m/30s (or 10m/minute, or some other number in furlongs per microfortnight). All kinds of weird and wonderful composite units are available - as some posters mentioned earlier. Or consider electrical units - Amps are Coulombs per second, Volts are Joules per Coulomb, and Watts are Joules per second - or something like that - it's been a while. Which raises interesting possibilities for *display* of numbers with units attached, when they need to be scaled, or converted between families of units that measure the same thing, or expressed (as for Current) in a particular way.

As for how to do that in Pythin, I've no idea. But it's a fascinating problem.