Safe Haskell	None

BundledPatterns2

Synopsis

Documentation

data Vec :: Nat -> * -> * where #

Fixed size vectors.

Lists with their length encoded in their type
Vector elements have an ASCENDING subscript starting from 0 and + ending at length - 1.

Bundled Patterns

pattern Empty :: Vec 0 a

pattern (:>) :: a -> Vec n a -> Vec (n + 1) a infixr 5

Add an element to the head of a vector.

>>> 3:>4:>5:>Nil
+<3,4,5>
+>>> let x = 3:>4:>5:>Nil
+>>> :t x
+x :: Num a => Vec 3 a
+

Can be used as a pattern:

>>> let f (x :> y :> _) = x + y
+>>> :t f
+f :: Num a => Vec ((n + 1) + 1) a -> a
+>>> f (3:>4:>5:>6:>7:>Nil)
+7
+

Also in conjunctions with (:<):

>>> let g (a :> b :> (_ :< y :< x)) = a + b +  x + y
+>>> :t g
+g :: Num a => Vec ((((n + 1) + 1) + 1) + 1) a -> a
+>>> g (1:>2:>3:>4:>5:>Nil)
+12
+

data RTree :: Nat -> * -> * where #

Perfect depth binary tree.

Bundled Patterns

pattern LR :: a -> RTree 0 a

Leaf of a perfect depth tree

>>> LR 1
+1
+>>> let x = LR 1
+>>> :t x
+x :: Num a => RTree 0 a
+

Can be used as a pattern:

>>> let f (LR a) (LR b) = a + b
+>>> :t f
+f :: Num a => RTree 0 a -> RTree 0 a -> a
+>>> f (LR 1) (LR 2)
+3
+

pattern BR :: RTree d a -> RTree d a -> RTree (d + 1) a

Branch of a perfect depth tree

>>> BR (LR 1) (LR 2)
+<1,2>
+>>> let x = BR (LR 1) (LR 2)
+>>> :t x
+x :: Num a => RTree 1 a
+

Case be used a pattern:

>>> let f (BR (LR a) (LR b)) = LR (a + b)
+>>> :t f
+f :: Num a => RTree 1 a -> RTree 0 a
+>>> f (BR (LR 1) (LR 2))
+3
+