I am pleased to announce version 0.9 of my dimensional library for arithmetic with statically checked physical dimensions. The differences from version 0.8.2.1 is the specification of fixity for `*~~`

and `/~~`

and their generalization to operate on functors rather than lists. The lack of fixity specifications was a bug; I had always intended them to have the same fixity as the closely related `*~`

and `/~`

(and `*`

and `/`

for that matter).

For readers unfamiliar with the above operators they are used to relate numerical values with units in order to construct and deconstruct physical quantities. For example:

`> import Numeric.Units.Dimensional.Prelude`

> import qualified Prelude

`> x :: Length Double -- type Length = Quantity DLength`

> x = 1 *~ meter

`> y :: Double`

> y = x /~ kilo meter -- 0.001

This convention for constructing and deconstructing quantities by multiplication and division respectively is motivated by the *NIST Guide to the SI*, section 7.1.

The `*~~`

and `/~~`

operators are analogous to `*~`

and `/~`

but operate on functors, e.g.:

`> xs :: [Length Double]`

> xs = [1..] *~~ meter

`> ys :: [Double]`

> ys = xs /~~ kilo meter

Finally an observation for the Haskell community: the Haskell package versioning policy does not address fixity changes, which I presume should force a major version change. Unless someone either objects or beats me to it I will update the wiki to reflect this.