-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Create and transform functions with variable arity.
--   
--   Please see the README on GitHub at
--   <a>https://github.com/lykahb/variadic-function#readme</a>
@package variadic-function
@version 0.1.0.0

module Data.Function.Variadic

-- | Toolkit for creating and transforming functions with a variable number
--   of arguments. Its parameters are function, list of its arguments, its
--   result, and <tt>argC</tt> that constraints all arguments of the
--   function.
class (ConstructFunction args r ~ f, DeconstructFunction f ~ '(args, r)) => Function f args r argC

-- | Create a new function
--   
--   <h3><b>Example usage</b></h3>
--   
--   <pre>
--   &gt;&gt;&gt; printf :: Function Show f args String =&gt; f
--   
--   &gt;&gt;&gt; printf = createFunction (Proxy :: Proxy Show) (\acc a -&gt; acc &lt;&gt; show a) id ""
--   
--   &gt;&gt;&gt; printf "hello" () :: String
--   "hello()"
--   </pre>
createFunction :: Function f args r argC => proxy argC -> (forall a. argC a => acc -> a -> acc) -> (acc -> r) -> acc -> f

-- | Create a function with the same arguments as given one but may have a
--   different result.
transformFunction :: Function f args r argC => proxy argC -> (forall a. argC a => acc -> a -> acc) -> (acc -> r0 -> r) -> acc -> ConstructFunction args r0 -> f

-- | Given the types of function arguments and its result, make a type of a
--   function.
type family ConstructFunction (args :: [Type]) (r :: Type)

-- | Extract list of arguments and the result from the function.
type family DeconstructFunction (f :: Type) :: ([Type], Type)

-- | When the arguments are not constrained, use this as the argC parameter
--   of <a>Function</a>.
class EmptyConstraint a

-- | Combine constraints. For example, <tt>Function f args x (Show &amp;
--   Num)</tt>.
class (f x, g x) => (&) f g (x :: k)
instance forall k (f :: k -> GHC.Types.Constraint) (x :: k) (g :: k -> GHC.Types.Constraint). (f x, g x) => (Data.Function.Variadic.&) f g x
instance forall k (a :: k). Data.Function.Variadic.EmptyConstraint a
instance ('( '[], r) GHC.Types.~ Data.Function.Variadic.DeconstructFunction r) => Data.Function.Variadic.Function r '[] r argC
instance (Data.Function.Variadic.Function f args r argC, argC a) => Data.Function.Variadic.Function (a -> f) (a : args) r argC

module Data.Function.Variadic.Utils

-- | Function composition for an arbitrary number of arguments.
--   
--   <pre>
--   &gt;&gt;&gt; (show `composeN` \a b c -&gt; (a + b + c :: Int)) 1 2 3
--   "6"
--   </pre>
composeN :: (Function f args b EmptyConstraint, Function g args a EmptyConstraint) => (a -> b) -> g -> f

-- | Constant function for an arbitrary number of arguments.
--   
--   <pre>
--   let const2 = constN :: x -&gt; a -&gt; b -&gt; x
--   </pre>
--   
--   <pre>
--   &gt;&gt;&gt; zipWith3 (constN 1) [1..10] [1..5] ["a", "b", "c"] :: [Int]
--   [1,1,1]
--   </pre>
constN :: Function f args a EmptyConstraint => a -> f

-- | Append multiple monoid values. It is similar to <a>mconcat</a> but
--   takes the values as arguments rather than list elements.
--   
--   <pre>
--   &gt;&gt;&gt; mappendN [1, 2] [3] [4, 5] :: [Int]
--   [1,2,3,4,5]
--   </pre>
mappendN :: forall r f args. (Function f args r ((~) r), Monoid r) => f