Safe Haskell	None

Test.Feat.Modifiers

Contents

List modifiers
Numeric modifiers
Character and string modifiers

Description

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 .

Synopsis

List modifiers

newtype NonEmpty a Source

A type of non empty lists.

Constructors

NonEmpty
Fields nonEmpty :: [a]

Instances

Typeable1 NonEmpty
Show a => Show (NonEmpty a)
Enumerable a => Enumerable (NonEmpty a)

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

Numeric modifiers

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

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

Instances

Infinite Integer

newtype Nat a Source

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

Constructors

Nat
Fields nat :: a

Instances

Typeable1 Nat
Eq a => Eq (Nat a)
Ord a => Ord (Nat a)
Show a => Show (Nat a)
Infinite a => Enumerable (Nat a)

newtype NonZero a Source

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

Constructors

NonZero
Fields nonZero :: a

Instances

Typeable1 NonZero
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 Source

Any unicode character.

Constructors

Unicode
Fields unicode :: Char

Instances

Eq Unicode
Ord Unicode
Show Unicode
Typeable Unicode
Enumerable Unicode

unicodes :: [Unicode] -> String Source

Smart constructor for unicode strings.

newtype Printable Source

Printable ASCII characters

Constructors

Printable
Fields printable :: Char

Instances

Show Printable
Typeable Printable
Enumerable Printable

printables :: [Printable] -> String Source

Smart constructor for printable ASCII strings