Fcf

Note that this denotes the identity function, so ($) f can usually be replaced with f.

Specialization of Bimap for pairs.

Right fold.

Example

>>> :kind! Eval (Foldr (+) 0 [1, 2, 3, 4])Eval (Foldr (+) 0 [1, 2, 3, 4]) :: Natural= 10

This is Foldr with its argument flipped.

List catenation.

Example

>>> data Example where Ex :: a -> Example  -- Hide the type of examples to avoid brittleness in different GHC versions>>> :kind! Ex (Eval ([1, 2] ++ [3, 4]) :: [Natural])Ex (Eval ([1, 2] ++ [3, 4]) :: [Natural]) :: Example= Ex [1, 2, 3, 4]

Keep all elements that satisfy a predicate, remove all that don't.

Example

>>> :kind! Eval (Filter ((>) 3) [1,2,3,0])Eval (Filter ((>) 3) [1,2,3,0]) :: [Natural]= [1, 2, 0]

Find Just the first element satisfying a predicate, or evaluate to Nothing if no element satisfies the predicate.

Example

>>> :kind! Eval (Find (TyEq 0) [1,2,3])Eval (Find (TyEq 0) [1,2,3]) :: Maybe Natural= Nothing

>>> :kind! Eval (Find (TyEq 0) [1,2,3,0])Eval (Find (TyEq 0) [1,2,3,0]) :: Maybe Natural= Just 0

Find the index of an element satisfying the predicate.

Example

>>> :kind! Eval (FindIndex ((<=) 3) [1,2,3,1,2,3])Eval (FindIndex ((<=) 3) [1,2,3,1,2,3]) :: Maybe Natural= Just 2

>>> :kind! Eval (FindIndex ((>) 0) [1,2,3,1,2,3])Eval (FindIndex ((>) 0) [1,2,3,1,2,3]) :: Maybe Natural= Nothing

Find an element associated with a key in an association list.

Modify an element at a given index.

The list is unchanged if the index is out of bounds.

Example

>>> :kind! Eval (SetIndex 2 7 [1,2,3])Eval (SetIndex 2 7 [1,2,3]) :: [Natural]= [1, 2, 7]

Combine elements of two lists pairwise.

Example

>>> :kind! Eval (ZipWith (+) [1,2,3] [1,1,1])Eval (ZipWith (+) [1,2,3] [1,1,1]) :: [Natural]= [2, 3, 4]

Append elements to two lists. Used in the definition of Unzip.

N.B.: The order of the two branches is the opposite of "if": UnBool ifFalse ifTrue bool.

This mirrors the default order of constructors:

data Bool = False | True
----------- False < True

(Limited) equivalent of \case { .. } syntax. Supports matching of exact values (-->) and final matches for any value (Any) or for passing value to subcomputation (Else). Examples:

type BoolToNat = Case
  [ 'True  --> 0
  , 'False --> 1
  ]

type NatToBool = Case
  [ 0 --> 'False
  , Any   'True
  ]

type ZeroOneOrSucc = Case
  [ 0  --> 0
  , 1  --> 1
  , Else   ((+) 1)
  ]

Match concrete type in Case.

Match on predicate being successful with type in Case.

Match any type in Case. Should be used as a final branch.

Note: this identifier conflicts with Any (from Fcf.Class.Foldable) Any (from Data.Monoid), and Any (from GHC.Exts).

We recommend importing this one qualified.

Pass type being matched in Case to subcomputation. Should be used as a final branch.