Is it possible to implement F#'s infrastructure for Units of Measurement in Scala?

F# ships with special support for a unit of measurement system, which provides static type safety while compiling down to the numeric types instead of bu开发者_如何学编程rdening the runtime with wrapping/unwrapping operations.

Is it possible to use some of Scala's type system magic to implement something comparable to that?

The answer is no.

Now, someone is bound to point me to Scalar, but that gives runtime checking. Perhaps, then, point to the efforts of Jesper Nordenberg's type-safe units or Jim McBeath's take on it, but these are cumbersome and awkward.

I'll point, instead to the Units compiler plugin. It gave Scala, back in 2008/2009, a pretty good system of units, as can be seen in this post. It did so, however, by extending the compiler, which would not be necessary if the type system was enough. Alas, it has not been maintained and it doesn't work anymore.

I don't know anything about it, but I just stumbled accross this talk at Scala Days: https://wiki.scala-lang.org/display/SW/ScalaDays+2011+Resources#ScalaDays2011Resources-ScalaUImplementingaScalalibraryforUnitsofMeasure

Kind of. You can encode the SI units quite easily using a type representation of integers in a tuple of exponents. See http://svn.assembla.com/svn/metascala/src/metascala/Units.scala for an example implementation.

It should also be possible to support an extensible units system if the units are encoded as a TList of pairs of a unit type and an integer (for example, ((M, _1), (S, _2)) where M <: Unit and S <: Unit). Calculating the types for quantity operations becomes a bit more complicated in this encoding.

Regarding performance there will always be a memory overhead for wrapping the value in a type containing the unit information. However there is probably no performance overhead in the actual operations as all unit checking is done at compile time.

Have a look at Units of Measure - A Scala Macro System. It seems to satisfy your requirements.