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1. conFixity :: forall k1 t (f :: k1 -> Type) (a :: k1) . Constructor c => t c f a -> Fixity

   protolude	Protolude

   The fixity of the constructor

2. fix :: (a -> a) -> a

   protolude	Protolude

   fix f is the least fixed point of the function f, i.e. the least defined x such that f x = x. When f is strict, this means that because, by the definition of strictness, f ⊥ = ⊥ and such the least defined fixed point of any strict function is ⊥.

   Examples

   We can write the factorial function using direct recursion as

   >>> let fac n = if n <= 1 then 1 else n * fac (n-1) in fac 5
   120
   

   This uses the fact that Haskell’s let introduces recursive bindings. We can rewrite this definition using fix, Instead of making a recursive call, we introduce a dummy parameter rec; when used within fix, this parameter then refers to fix’s argument, hence the recursion is reintroduced.

   >>> fix (\rec n -> if n <= 1 then 1 else n * rec (n-1)) 5
   120
   

   Using fix, we can implement versions of repeat as fix . (:) and cycle as fix . (++)

   >>> take 10 $ fix (0:)
   [0,0,0,0,0,0,0,0,0,0]
   

   >>> map (fix (\rec n -> if n < 2 then n else rec (n - 1) + rec (n - 2))) [1..10]
   [1,1,2,3,5,8,13,21,34,55]
   

   Implementation Details

   The current implementation of fix uses structural sharing

   fix f = let x = f x in x
   

   A more straightforward but non-sharing version would look like

   fix f = f (fix f)
   

3. fixST :: (a -> ST s a) -> ST s a

   protolude	Protolude

   Allow the result of an ST computation to be used (lazily) inside the computation. Note that if f is strict, fixST f = _|_.

4. floatRadix :: RealFloat a => a -> Integer

   protolude	Protolude

   a constant function, returning the radix of the representation (often 2)

5. isInfixOf :: Eq a => [a] -> [a] -> Bool

   protolude	Protolude

   The isInfixOf function takes two lists and returns True iff the first list is contained, wholly and intact, anywhere within the second.

   Examples

   >>> isInfixOf "Haskell" "I really like Haskell."
   True
   

   >>> isInfixOf "Ial" "I really like Haskell."
   False
   

   For the result to be True, the first list must be finite; for the result to be False, the second list must be finite:

   >>> [20..50] `isInfixOf` [0..]
   True
   

   >>> [0..] `isInfixOf` [20..50]
   False
   

   >>> [0..] `isInfixOf` [0..]
   * Hangs forever *
   

6. isPrefixOf :: Eq a => [a] -> [a] -> Bool

   protolude	Protolude

   The isPrefixOf function takes two lists and returns True iff the first list is a prefix of the second.

   Examples

   >>> "Hello" `isPrefixOf` "Hello World!"
   True
   

   >>> "Hello" `isPrefixOf` "Wello Horld!"
   False
   

   For the result to be True, the first list must be finite; False, however, results from any mismatch:

   >>> [0..] `isPrefixOf` [1..]
   False
   

   >>> [0..] `isPrefixOf` [0..99]
   False
   

   >>> [0..99] `isPrefixOf` [0..]
   True
   

   >>> [0..] `isPrefixOf` [0..]
   * Hangs forever *
   

   isPrefixOf shortcuts when the first argument is empty:

   >>> isPrefixOf [] undefined
   True
   

7. isSuffixOf :: Eq a => [a] -> [a] -> Bool

   protolude	Protolude

   The isSuffixOf function takes two lists and returns True iff the first list is a suffix of the second.

   Examples

   >>> "ld!" `isSuffixOf` "Hello World!"
   True
   

   >>> "World" `isSuffixOf` "Hello World!"
   False
   

   The second list must be finite; however the first list may be infinite:

   >>> [0..] `isSuffixOf` [0..99]
   False
   

   >>> [0..99] `isSuffixOf` [0..]
   * Hangs forever *
   

8. floatRadix :: RealFloat a => a -> Integer

   protolude	Protolude.Base

   a constant function, returning the radix of the representation (often 2)

9. refix :: (Recursive s, Corecursive t, Base s ~ Base t) => s -> t

   recursion-schemes	Data.Functor.Foldable

   Convert from one recursive representation to another.

   >>> refix ["foo", "bar"] :: Fix (ListF String)
   Fix (Cons "foo" (Fix (Cons "bar" (Fix Nil))))
   

10. getUnixSocket :: forall (m :: Type -> Type) a . Config m a -> Maybe FilePath

    snap-server	Snap.Http.Server.Config

    File path to unix socket. Must be absolute path, but allows for symbolic links.

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