Penny.Lincoln.Bits.Price

Documentation

newtype From

Constructors

From

Fields

unFrom :: Commodity

Instances

Eq From

Ord From

Show From

newtype To

Constructors

To

Fields

unTo :: Commodity

Instances

Eq To

Ord To

Show To

newtype CountPerUnit

Constructors

CountPerUnit

Fields

unCountPerUnit :: QtyRep

Instances

Eq CountPerUnit

Ord CountPerUnit

Show CountPerUnit

Equivalent CountPerUnit

data Price

Instances

Eq Price

Ord Price

Show Price

Equivalent Price

Two Price are equivalent if the From and To are equal and the CountPerUnit is equivalent.

newPrice :: From -> To -> CountPerUnit -> Maybe Price

Succeeds only if From and To are different commodities.