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


-- | instantly create REPL from any function
--   
--   This module provides functions to create interactive REPLs:
--   
--   <ul>
--   <li>stateless REPL from a single argument functions</li>
--   <li>REPL with state from plain state function or with State monad</li>
--   <li>REPL-fold from two-arguments functions, with the accumulator in
--   the first argument</li>
--   </ul>
--   
--   Each line you enter is <a>read</a> into the argument type and sent to
--   the function, with the result printed
@package interact
@version 0.1.0.0


-- | This module provides functions to instantly create interactive REPL,
--   similar to Prelude <a>interact</a> but with line-by-line processing:
--   
--   <ul>
--   <li>stateless REPL from a single argument functions</li>
--   <li>REPL with state from plain state function or with State monad</li>
--   <li>REPL-fold from two-arguments functions, with the accumulator in
--   the first argument</li>
--   </ul>
--   
--   Each line you enter is <a>read</a> into the argument type and sent to
--   the function, with the result printed.
module System.IO.Interact

-- | <a>Repl</a> typeclass with polymorphic stateless function <a>repl</a>
--   to interactively evaluate input lines and print responses (see below).
class Repl a b

-- | Function passed to <a>repl</a> will be called with values from
--   <tt>stdin</tt> (<a>String</a>s or <a>Read</a> instances, one value at
--   a time or as a lazy list depending on the type of the function) and
--   should return value to be printed to <tt>stdout</tt> (<a>String</a> or
--   <a>Show</a> instance, possibly wrapped in <a>Maybe</a> or
--   <a>Either</a>, one value at a time or as a lazy list) .
--   
--   Specific behaviour depends on function type (see instances above).
--   
--   <b>Examples</b>:
--   
--   Print square roots of the entered numbers:
--   
--   <pre>
--   repl (sqrt :: Double -&gt; Double)
--   </pre>
--   
--   Reverse entered strings:
--   
--   <pre>
--   repl (reverse :: String -&gt; String)
--   </pre>
--   
--   Prints both squares and square roots:
--   
--   <pre>
--   sqrSqrt :: [Double] -&gt; [Double]
--   sqrSqrt [] = []
--   sqrSqrt (x:xs) = x^2 : sqrt x : sqrSqrt xs
--   repl sqrSqrt
--   </pre>
repl :: Repl a b => (a -> b) -> IO ()

-- | Same as <a>repl</a> with <tt>(a -&gt; b)</tt> function but the first
--   argument is the value that will cause <a>repl'</a> to exit.
repl' :: (Eq a, Read a, Show b) => a -> (a -> b) -> IO ()

-- | <a>ReplState</a> typeclass with polymorphic stateful function
--   <a>replState</a> to interactively evaluate input lines and print
--   responses (see below).
class ReplState a b s | b -> s

-- | Function passed to <a>replState</a> will be called with values from
--   <tt>stdin</tt> and previous state (depending on type, via State monad
--   or as the first argument) and should return value to be printed to
--   <tt>stdout</tt> and the new state (either via State monad or as a
--   tuple).
--   
--   Specific behaviour depends on function type (see instances above).
--   
--   <b>Examples</b>:
--   
--   Prints sums of entered numbers:
--   
--   <pre>
--   adder :: Int -&gt; State Int Int
--   adder x = modify (+ x) &gt;&gt; get
--   replState adder 0
--   </pre>
--   
--   or with plain state function
--   
--   <pre>
--   adder :: Int -&gt; Int -&gt; (Int, Int)
--   adder x s = let s' = s + x in (s', s')
--   replState adder 0
--   </pre>
--   
--   Above can be done with <a>replFold</a> (see below):
--   
--   <pre>
--   replFold (+) 0
--   </pre>
--   
--   but replState is more flexible - state and output can be different
--   types.
replState :: ReplState a b s => (a -> b) -> s -> IO ()

-- | Same as <a>replState</a> with <tt>(a -&gt; State s b)</tt> function
--   but the first argument is the value that will cause <a>replState'</a>
--   to exit.
replState' :: forall a b s. (Eq a, Read a, Show b) => a -> (a -> State s b) -> s -> IO ()

-- | <a>replFold</a> combines the entered values with the accumulated value
--   using provided function and prints the resulting values.
replFold :: forall a b. (Read a, Show b) => (b -> a -> b) -> b -> IO ()

-- | Same as <a>replFold</a> but the first argument is the value that will
--   cause <a>replFold'</a> to exit.
replFold' :: forall a b. (Eq a, Read a, Show b) => a -> (b -> a -> b) -> b -> IO ()
instance System.IO.Interact.ReplState GHC.Base.String (s -> (GHC.Base.String, s)) s
instance (GHC.Read.Read a, GHC.Show.Show b) => System.IO.Interact.ReplState a (s -> (b, s)) s
instance System.IO.Interact.ReplState [GHC.Base.String] (Control.Monad.Trans.State.Lazy.State s [GHC.Base.String]) s
instance (GHC.Read.Read a, GHC.Show.Show b) => System.IO.Interact.ReplState a (Control.Monad.Trans.State.Lazy.State s b) s
instance System.IO.Interact.ReplState GHC.Base.String (Control.Monad.Trans.State.Lazy.State s GHC.Base.String) s
instance System.IO.Interact.ReplState GHC.Base.String (Control.Monad.Trans.State.Lazy.State s (GHC.Maybe.Maybe GHC.Base.String)) s
instance System.IO.Interact.ReplState GHC.Base.String (Control.Monad.Trans.State.Lazy.State s (Data.Either.Either GHC.Base.String GHC.Base.String)) s
instance (GHC.Read.Read a, GHC.Show.Show b) => System.IO.Interact.ReplState a (Control.Monad.Trans.State.Lazy.State s (GHC.Maybe.Maybe b)) s
instance (GHC.Read.Read a, GHC.Show.Show b) => System.IO.Interact.ReplState a (Control.Monad.Trans.State.Lazy.State s (Data.Either.Either GHC.Base.String b)) s
instance System.IO.Interact.Repl [GHC.Base.String] [GHC.Base.String]
instance (GHC.Read.Read a, GHC.Show.Show b) => System.IO.Interact.Repl [a] [b]
instance (GHC.Read.Read a, GHC.Show.Show b) => System.IO.Interact.Repl a b
instance System.IO.Interact.Repl GHC.Base.String GHC.Base.String
instance System.IO.Interact.Repl GHC.Base.String (GHC.Maybe.Maybe GHC.Base.String)
instance System.IO.Interact.Repl GHC.Base.String (Data.Either.Either GHC.Base.String GHC.Base.String)
instance (GHC.Read.Read a, GHC.Show.Show b) => System.IO.Interact.Repl a (GHC.Maybe.Maybe b)
instance (GHC.Read.Read a, GHC.Show.Show b) => System.IO.Interact.Repl a (Data.Either.Either GHC.Base.String b)