diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,22 @@
+Copyright (c) 2017, Nikita Volkov
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/lazy.cabal b/lazy.cabal
new file mode 100644
--- /dev/null
+++ b/lazy.cabal
@@ -0,0 +1,56 @@
+name:
+  lazy
+version:
+  0.1
+category:
+  Control
+synopsis:
+  Explicit laziness for Haskell
+description:
+  Now that we have the \"Strict\" pragma at hand we can finally work in Haskell as in a strict language.
+  Sometimes though laziness is useful,
+  but all Haskellers also know that types keep us safe.
+  This library provides laziness as an abstraction with an explicit type-signature,
+  and it so happens that this abstraction forms a monad!
+  .
+  This library takes inspiration from the following blog post:
+  <https://nikita-volkov.github.io/if-haskell-were-strict/>
+homepage:
+  https://github.com/nikita-volkov/lazy
+bug-reports:
+  https://github.com/nikita-volkov/lazy/issues
+author:
+  Nikita Volkov <nikita.y.volkov@mail.ru>
+maintainer:
+  Nikita Volkov <nikita.y.volkov@mail.ru>
+copyright:
+  (c) 2017, Nikita Volkov
+license:
+  MIT
+license-file:
+  LICENSE
+build-type:
+  Simple
+cabal-version:
+  >=1.24
+
+source-repository head
+  type:
+    git
+  location:
+    git://github.com/nikita-volkov/lazy.git
+
+library
+  hs-source-dirs:
+    library
+  default-extensions:
+    Arrows, BangPatterns, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFoldable, DeriveFunctor, DeriveGeneric, DeriveTraversable, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, PatternSynonyms, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, TemplateHaskell, TupleSections, TypeFamilies, TypeOperators, UnboxedTuples
+  default-language:
+    Haskell2010
+  exposed-modules:
+    Lazy
+  other-modules:
+    Lazy.Prelude
+  build-depends:
+    comonad >=5 && <6,
+    base >=4.6 && <5
diff --git a/library/Lazy.hs b/library/Lazy.hs
new file mode 100644
--- /dev/null
+++ b/library/Lazy.hs
@@ -0,0 +1,64 @@
+module Lazy
+(
+  Lazy,
+  lazy,
+  unlazy,
+)
+where
+
+import Lazy.Prelude hiding (lazy)
+
+
+newtype Lazy value = Lazy (IO value)
+
+instance Functor Lazy where
+  {-# INLINE fmap #-}
+  fmap mapping (Lazy io) =
+    Lazy (fmap mapping io)
+
+instance Applicative Lazy where
+  pure = lazy
+  {-# INLINE (<*>) #-}
+  (<*>) (Lazy leftIO) (Lazy rightIO) =
+    Lazy (leftIO <*> rightIO)
+
+instance Monad Lazy where
+  return = pure
+  {-# INLINE (>>=) #-}
+  (>>=) (Lazy leftIO) rightK =
+    Lazy $ do
+      leftValue <- leftIO
+      case rightK leftValue of
+        Lazy rightIO -> rightIO
+
+instance Comonad Lazy where
+  extract = unlazy
+  extend leftK right =
+    lazy (leftK right)
+
+
+data LazyState value = UnevaluatedLazyState value | EvaluatedLazyState !value
+
+
+{-# INLINE lazy #-}
+lazy :: value -> Lazy value
+lazy value =
+  unsafeDupablePerformIO $ do
+    stateRef <- newIORef (UnevaluatedLazyState value)
+    return $ Lazy $ do
+      state <- readIORef stateRef
+      case state of
+        EvaluatedLazyState !value -> return value
+        UnevaluatedLazyState !value -> do
+          writeIORef stateRef (EvaluatedLazyState value)
+          return value
+
+{-# INLINE unlazy #-}
+unlazy :: Lazy value -> value
+unlazy (Lazy io) =
+  -- Synchronisation is not an issue here,
+  -- since there's nothing dangerous in two threads
+  -- occasionally computing the same result.
+  -- That would be the price of not having 
+  -- to pay for locks-maintenance overhead.
+  unsafeDupablePerformIO io
diff --git a/library/Lazy/Prelude.hs b/library/Lazy/Prelude.hs
new file mode 100644
--- /dev/null
+++ b/library/Lazy/Prelude.hs
@@ -0,0 +1,224 @@
+{-# LANGUAGE CPP #-}
+-- |
+-- This module reexports most of the definitions from the \"base\" package,
+-- which are meant to be imported unqualified.
+--
+-- For details check out the source.
+module Lazy.Prelude
+(
+  module Exports,
+  -- * Reimplementations of functions presented in versions of \"base\" newer than 4.6
+  -- ** Data.Bool
+  bool,
+  -- ** Data.Function
+  (&),
+  -- ** Data.Functor
+  ($>),
+  -- ** Data.List
+  isSubsequenceOf,
+  sortOn,
+  uncons,
+  -- ** Debug.Trace
+  traceShowId,
+  traceM,
+  traceShowM,
+)
+where
+
+-- Reexports
+-------------------------
+
+import Control.Applicative as Exports
+import Control.Arrow as Exports hiding (first, second)
+import Control.Category as Exports
+import Control.Concurrent as Exports
+import Control.Comonad as Exports hiding (($>))
+import Control.Exception as Exports
+import Control.Monad as Exports hiding (mapM_, sequence_, forM_, msum, mapM, sequence, forM)
+import Control.Monad.Fix as Exports hiding (fix)
+import Control.Monad.ST as Exports
+import Data.Bits as Exports
+import Data.Bool as Exports hiding (bool)
+import Data.Char as Exports
+import Data.Complex as Exports
+import Data.Data as Exports
+import Data.Dynamic as Exports
+import Data.Either as Exports
+import Data.Fixed as Exports
+import Data.Foldable as Exports
+import Data.Functor as Exports hiding (($>))
+import Data.Function as Exports hiding ((.), id, (&))
+import Data.Int as Exports
+import Data.IORef as Exports
+import Data.Ix as Exports
+import Data.List as Exports hiding (sortOn, isSubsequenceOf, uncons, concat, foldr, foldl1, maximum, minimum, product, sum, all, and, any, concatMap, elem, foldl, foldr1, notElem, or, find, maximumBy, minimumBy, mapAccumL, mapAccumR, foldl')
+import Data.Maybe as Exports
+import Data.Monoid as Exports
+import Data.Ord as Exports
+import Data.Ratio as Exports
+import Data.STRef as Exports
+import Data.String as Exports
+import Data.Traversable as Exports
+import Data.Tuple as Exports
+import Data.Unique as Exports
+import Data.Version as Exports
+import Data.Word as Exports
+import Debug.Trace as Exports hiding (traceShowId, traceM, traceShowM)
+import Foreign.Storable as Exports
+import Foreign.Ptr as Exports
+import Foreign.ForeignPtr as Exports
+import Foreign.StablePtr as Exports
+import GHC.Conc as Exports hiding (withMVar, threadWaitWriteSTM, threadWaitWrite, threadWaitReadSTM, threadWaitRead)
+import GHC.Exts as Exports (lazy, inline, sortWith, groupWith)
+import GHC.Generics as Exports (Generic)
+import GHC.IO.Exception as Exports
+import Numeric as Exports
+import Prelude as Exports hiding (concat, foldr, mapM_, sequence_, foldl1, maximum, minimum, product, sum, all, and, any, concatMap, elem, foldl, foldr1, notElem, or, mapM, sequence, id, (.))
+import System.Environment as Exports
+import System.Exit as Exports
+import System.IO as Exports (Handle, hClose)
+import System.IO.Error as Exports
+import System.IO.Unsafe as Exports
+import System.Mem as Exports
+import System.Mem.StableName as Exports
+import System.Timeout as Exports
+import Text.ParserCombinators.ReadP as Exports (ReadP, ReadS, readP_to_S, readS_to_P)
+import Text.ParserCombinators.ReadPrec as Exports (ReadPrec, readPrec_to_P, readP_to_Prec, readPrec_to_S, readS_to_Prec)
+import Text.Printf as Exports (printf, hPrintf)
+import Text.Read as Exports (Read(..), readMaybe, readEither)
+import Unsafe.Coerce as Exports
+
+-- Conditional imports for newer bases
+#if MIN_VERSION_base(4,7,0)
+import Data.Coerce as Exports
+import Data.Proxy as Exports
+#endif
+#if MIN_VERSION_base(4,8,0)
+import Data.Bifunctor as Exports
+import Data.Functor.Identity as Exports
+import Data.Void as Exports
+import Numeric.Natural as Exports
+#endif
+#if MIN_VERSION_base(4,9,0)
+import Control.Monad.Fail as Exports (MonadFail)
+import Control.Monad.IO.Class as Exports
+import Data.Functor.Classes as Exports
+import Data.Functor.Compose as Exports
+import Data.List.NonEmpty as Exports (NonEmpty(..))
+import Data.Semigroup as Exports hiding ((<>), First(..), Last(..))
+#endif
+
+-- Conditional imports for reimplementations
+#if MIN_VERSION_base(4,7,0)
+import Data.Bool (bool)
+import Debug.Trace (traceShowId, traceM, traceShowM)
+import Data.Functor (($>))
+#endif
+#if MIN_VERSION_base(4,8,0)
+import Data.Function ((&))
+import Data.List (isSubsequenceOf, sortOn, uncons)
+#endif
+
+
+---------------------------------
+-- Reimplementations for base-4.7
+---------------------------------
+
+#if !MIN_VERSION_base(4,7,0)
+
+-- | Case analysis for the 'Bool' type.
+-- @bool a b p@ evaluates to @a@ when @p@ is @False@, and evaluates to @b@
+-- when @p@ is @True@.
+bool :: a -> a -> Bool -> a
+bool f t b = if b then t else f
+
+{-|
+Like 'traceShow' but returns the shown value instead of a third value.
+-}
+traceShowId :: (Show a) => a -> a
+traceShowId a = trace (show a) a
+
+{-|
+Like 'trace' but returning unit in an arbitrary monad. Allows for convenient
+use in do-notation. Note that the application of 'trace' is not an action in the
+monad, as 'traceIO' is in the 'IO' monad.
+
+> ... = do
+>   x <- ...
+>   traceM $ "x: " ++ show x
+>   y <- ...
+>   traceM $ "y: " ++ show y
+-}
+traceM :: (Monad m) => String -> m ()
+traceM string = trace string $ return ()
+
+{-|
+Like 'traceM', but uses 'show' on the argument to convert it to a 'String'.
+
+> ... = do
+>   x <- ...
+>   traceShowM $ x
+>   y <- ...
+>   traceShowM $ x + y
+-}
+traceShowM :: (Show a, Monad m) => a -> m ()
+traceShowM = traceM . show
+
+infixl 4 $>
+
+-- | Flipped version of '<$'.
+($>) :: Functor f => f a -> b -> f b
+($>) = flip (<$)
+
+#endif
+
+---------------------------------
+-- Reimplementations for base-4.8
+---------------------------------
+
+#if !MIN_VERSION_base(4,8,0)
+
+infixl 1 &
+
+-- | '&' is a reverse application operator.  This provides notational
+-- convenience.  Its precedence is one higher than that of the forward
+-- application operator '$', which allows '&' to be nested in '$'.
+(&) :: a -> (a -> b) -> b
+x & f = f x
+
+-- | The 'isSubsequenceOf' function takes two lists and returns 'True' if the
+-- first list is a subsequence of the second list.
+--
+-- @'isSubsequenceOf' x y@ is equivalent to @'elem' x ('subsequences' y)@.
+--
+-- ==== __Examples__
+--
+-- >>> isSubsequenceOf "GHC" "The Glorious Haskell Compiler"
+-- True
+-- >>> isSubsequenceOf ['a','d'..'z'] ['a'..'z']
+-- True
+-- >>> isSubsequenceOf [1..10] [10,9..0]
+-- False
+isSubsequenceOf :: (Eq a) => [a] -> [a] -> Bool
+isSubsequenceOf []    _                    = True
+isSubsequenceOf _     []                   = False
+isSubsequenceOf a@(x:a') (y:b) | x == y    = isSubsequenceOf a' b
+                               | otherwise = isSubsequenceOf a b
+
+-- | Decompose a list into its head and tail. If the list is empty,
+-- returns 'Nothing'. If the list is non-empty, returns @'Just' (x, xs)@,
+-- where @x@ is the head of the list and @xs@ its tail.
+uncons        :: [a] -> Maybe (a, [a])
+uncons []     = Nothing
+uncons (x:xs) = Just (x, xs)
+
+-- | Sort a list by comparing the results of a key function applied to each
+-- element.  @sortOn f@ is equivalent to @sortBy . comparing f@, but has the
+-- performance advantage of only evaluating @f@ once for each element in the
+-- input list.  This is called the decorate-sort-undecorate paradigm, or
+-- Schwartzian transform.
+sortOn :: Ord b => (a -> b) -> [a] -> [a]
+sortOn f =
+  map snd . sortBy (comparing fst) . map (\x -> let y = f x in y `seq` (y, x))
+
+#endif