Elm makes great use of these, for example in the Units package: https://package.elm-lang.org/packages/ianmackenzie/elm-units/latest/ https://package.elm-lang.o

Elm makes great use of these, for example in the Units package: https://package.elm-lang.org/packages/ianmackenzie/elm-units/latest/ https://package.elm-lang.org/packages/ianmackenzie/elm-units... Very nice to prevent conversions between incompatible units, but without the over head of lots of type variants. https://thoughtbot.com/blog/modeling-currency-in-elm-using-phantom-types https://thoughtbot.com/blog/modeling-currency-in-elm-using-p...