Test.Feat.Modifiers

Modifiers for types, i.e. newtype wrappers where the values satisfy some constraint (non-empty, positive etc.). Suggestions on useful types are appreciated.

To apply the modifiers types you can use the record label. For instance:

 data C a = C [a] [a] deriving Typeable
 instance Enumerable a => Enumerable (C a) where
    enumerate = unary $ funcurry $ 
      \xs ys -> C (nonEmpty xs) (nonEmpty ys)

Alternatively you can put everything in pattern postition:

 instance Enumerable a => Enumerable (C a) where
    enumerate = unary $ funcurry $ 
      \(Free (NonEmpty xs,NonEmpty ys)) -> C xs ys)

The first approach has the advantage of being usable with a point free style: \xs -> C (nonEmpty xs) . nonEmpty .

List modifiers

newtype NonEmpty a

A type of non empty lists.

Constructors

NonEmpty

Fields

nonEmpty :: [a]

Instances

Show a => Show (NonEmpty a)

Enumerable a => Enumerable (NonEmpty a)

mkNonEmpty :: (a, [a]) -> NonEmpty a

Numeric modifiers

class (Typeable a, Integral a) => Infinite a

A class of infinite precision integral types. Integer is the principal class member.

Instances

Infinite Integer

newtype Nat a

A type of (infinite precision) natural numbers such that nat a >= 0 .

Constructors

Nat

Fields

nat :: a

Instances

Eq a => Eq (Nat a)

Ord a => Ord (Nat a)

Show a => Show (Nat a)

Infinite a => Enumerable (Nat a)

newtype NonZero a

A type of (infinite precision) non-zero integers such that nonZero a /= 0 .

Constructors

NonZero

Fields

nonZero :: a

Instances

Eq a => Eq (NonZero a)

Ord a => Ord (NonZero a)

Show a => Show (NonZero a)

(Infinite a, Enumerable a) => Enumerable (NonZero a)

Character and string modifiers

newtype Unicode

Any unicode character.

Constructors

Unicode

Fields

unicode :: Char

Instances

Eq Unicode

Ord Unicode

Show Unicode

Enumerable Unicode

unicodes :: [Unicode] -> String

Smart constructor for unicode strings.

newtype Printable

Printable ASCII characters

Constructors

Printable

Fields

printable :: Char

Instances

Show Printable

Enumerable Printable

printables :: [Printable] -> String

Smart constructor for printable ASCII strings