module Unit:sig..end
type'aquantity =float * 'a option
typeangle =[ `Deg | `Grad | `Rad ] quantity
typelength =[ `Cm | `Em | `Ex | `In | `Mm | `Pc | `Percent | `Pt | `Px ]
quantity
typetime =[ `Ms | `S ] quantity
typefrequency =[ `Hz | `KHz ] quantity