Re: [Haskell-cafe] generic way to construct and deconstruct a newtype

If I look at the definition of an unit in dimensional I have this angstrom :: (Fractional a) => Unit 'NonMetric DLength a angstrom = mkUnitQ (ucum "Ao" "Å" "Ångström") 0.1 $ nano meter metre, meter :: Num a => Unit 'Metric DLength a metre = mkUnitZ I.nMeter 1 siUnit -- International English. meter = metre -- American English. So it seems thaht I can not differenciate angstrom and metter at the type level.