diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright Author name here © 2018
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
@@ -0,0 +1,1 @@
+# c
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/bench/Main.hs b/bench/Main.hs
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--- /dev/null
+++ b/bench/Main.hs
@@ -0,0 +1,6 @@
+module Main where
+
+import Criterion.Main
+
+main :: IO ()
+main = defaultMain []
diff --git a/compositional-data.cabal b/compositional-data.cabal
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--- /dev/null
+++ b/compositional-data.cabal
@@ -0,0 +1,115 @@
+name:                compositional-data
+version:             0.1.0.0
+synopsis:            Compositional Data Types
+description:         Modular data types defined as fixpoints, and term homomorphisms, like compdata package but with cleaner API
+license:             BSD3
+license-file:        LICENSE
+author:              M Farkas-Dyck
+maintainer:          strake888@gmail.com
+copyright:           2018 M Farkas-Dyck
+category:            Data
+build-type:          Simple
+extra-source-files:  README.md
+cabal-version:       >=1.10
+
+library
+  hs-source-dirs:      src
+  exposed-modules:     Control.Monad.Trans.Fresh
+                     , Data.Comp.Equality
+                     , Data.Comp.Show
+                     , Data.Comp.Term
+  other-modules:       Prelude
+  build-depends:       base >= 4.7 && < 5
+                     , bifunctor >= 0.1 && < 0.2
+                     , category >= 0.2.0.1 && < 0.3
+                     , transformers >= 0.5 && < 0.6
+                     , util >= 0.1.11 && < 0.2
+  default-language:    Haskell2010
+  default-extensions:  UnicodeSyntax
+                     , LambdaCase
+                     , EmptyCase
+                     , InstanceSigs
+                     , PartialTypeSignatures
+                     , RankNTypes
+                     , PolyKinds
+                     , ConstraintKinds
+                     , FlexibleContexts
+                     , FlexibleInstances
+                     , MultiParamTypeClasses
+                     , MonadComprehensions
+                     , DerivingStrategies
+                     , StandaloneDeriving
+                     , GeneralizedNewtypeDeriving
+                     , DeriveFunctor, DeriveFoldable, DeriveTraversable
+                     , PackageImports
+  ghc-options:         -Wall -Wcompat -Wredundant-constraints -Wno-name-shadowing
+                       -Wincomplete-record-updates -Wincomplete-uni-patterns
+                       -Werror=incomplete-patterns
+                       -Werror=incomplete-uni-patterns
+                       -Werror=incomplete-record-updates
+                       -Werror=missing-fields
+                       -Werror=missing-methods
+                       -Wno-partial-type-signatures
+                       -Wno-unticked-promoted-constructors
+
+test-suite test
+  type:                exitcode-stdio-1.0
+  hs-source-dirs:      test
+  main-is:             Main.hs
+  build-depends:       base >=4.11 && <5
+                     , smallcheck >=1.1.4
+                     , tasty >=1.0
+                     , tasty-smallcheck >=0.8
+                     , c
+  default-language:    Haskell2010
+  default-extensions:  UnicodeSyntax
+                     , LambdaCase
+                     , EmptyCase
+                     , InstanceSigs
+                     , PartialTypeSignatures
+                     , PolyKinds
+                     , ConstraintKinds
+                     , FlexibleContexts
+                     , FlexibleInstances
+                     , MonadComprehensions
+                     , StandaloneDeriving
+                     , DeriveFunctor, DeriveFoldable, DeriveTraversable
+  ghc-options:         -Wall -Wcompat -Wredundant-constraints -Wno-name-shadowing
+                       -Wincomplete-record-updates -Wincomplete-uni-patterns
+                       -Werror=incomplete-patterns
+                       -Werror=incomplete-uni-patterns
+                       -Werror=incomplete-record-updates
+                       -Werror=missing-fields
+                       -Werror=missing-methods
+
+benchmark bench
+  type:                exitcode-stdio-1.0
+  hs-source-dirs:      bench
+  main-is:             Main.hs
+  build-depends:       base >=4.11 && <5
+                     , criterion >=1.4.1
+                     , c
+  default-language:    Haskell2010
+  default-extensions:  UnicodeSyntax
+                     , LambdaCase
+                     , EmptyCase
+                     , InstanceSigs
+                     , PartialTypeSignatures
+                     , PolyKinds
+                     , ConstraintKinds
+                     , FlexibleContexts
+                     , FlexibleInstances
+                     , MonadComprehensions
+                     , StandaloneDeriving
+                     , DeriveFunctor, DeriveFoldable, DeriveTraversable
+  ghc-options:         -Wall -Wcompat -Wredundant-constraints -Wno-name-shadowing
+                       -Wincomplete-record-updates -Wincomplete-uni-patterns
+                       -Werror=incomplete-patterns
+                       -Werror=incomplete-uni-patterns
+                       -Werror=incomplete-record-updates
+                       -Werror=missing-fields
+                       -Werror=missing-methods
+
+source-repository head
+  type:     git
+  location: https://github.com/githubuser/c.hs
diff --git a/src/Control/Monad/Trans/Fresh.hs b/src/Control/Monad/Trans/Fresh.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Monad/Trans/Fresh.hs
@@ -0,0 +1,33 @@
+module Control.Monad.Trans.Fresh (FreshT, evalFreshT, Fresh, evalFresh, withName, Name) where
+
+import "base" Prelude (Show (..), (+), flip, ($), Eq (..))
+import qualified "base" Data.Functor as Hs
+
+import Control.Applicative (Applicative (..), Alternative (..))
+import Control.Monad (Monad (..), MonadPlus (..))
+import Control.Monad.Trans.Reader
+import qualified Data.List as List (genericIndex, reverse)
+
+newtype FreshT m a = FreshT { unFreshT :: ReaderT Natural m a }
+  deriving newtype (Hs.Functor, Applicative, Monad, Alternative, MonadPlus)
+
+newtype Name i = Name Natural
+  deriving (Eq)
+
+instance Category s => Functor s (->) Name where
+    map _ (Name n) = Name n
+
+instance Show (Name i) where
+    show (Name n) = List.genericIndex names n
+      where names = map List.reverse $ flip (:) <$> "":names <*> ['a'..'c']
+
+evalFreshT :: FreshT m a -> m a
+evalFreshT = flip runReaderT 0 . unFreshT
+
+type Fresh = FreshT Identity
+
+evalFresh :: Fresh a -> a
+evalFresh = runIdentity . evalFreshT
+
+withName :: Monad m => (Name i -> FreshT m a) -> FreshT m a
+withName f = FreshT (asks Name) >>= FreshT . local (+1) . unFreshT . f
diff --git a/src/Data/Comp/Equality.hs b/src/Data/Comp/Equality.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Comp/Equality.hs
@@ -0,0 +1,22 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+
+module Data.Comp.Equality where
+
+import Control.Applicative
+import Control.Categorical.Functor
+import Control.Category.Const2
+import Control.Monad.Trans.Fresh
+import Data.Bool
+import Data.Eq
+
+class PEq a where
+    peq :: a i -> a j -> Fresh Bool
+
+instance Eq a => PEq (Const a) where
+    peq (Const x) (Const y) = pure (x == y)
+
+instance PEq Name where
+    peq x y = pure (map (Const2 ()) x == y)
+
+class EqH f where
+    eqH :: PEq a => f Name a i -> f Name a j -> Fresh Bool
diff --git a/src/Data/Comp/Show.hs b/src/Data/Comp/Show.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Comp/Show.hs
@@ -0,0 +1,6 @@
+module Data.Comp.Show where
+
+import Control.Monad.Trans.Fresh
+
+class ShowH f where
+    showH :: f Name (Const (Fresh [Char])) i -> Fresh [Char]
diff --git a/src/Data/Comp/Term.hs b/src/Data/Comp/Term.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Comp/Term.hs
@@ -0,0 +1,63 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE UndecidableInstances #-}
+
+module Data.Comp.Term where
+
+import "base" Prelude (($), Show (..), Eq (..), Applicative (..))
+import Unsafe.Coerce
+
+import Control.Monad.Trans.Fresh
+import Data.Comp.Equality
+import Data.Comp.Show
+
+data Cxt (h :: Bool) f a b i where
+    In :: f a (Cxt h f a b) i -> Cxt h f a b i
+    Hole :: b i -> Cxt True f a b i
+    Var :: a i -> Cxt h f a b i
+
+newtype Term f i = Term { unTerm :: ∀ a . Trm f a i }
+
+type Trm f a = Cxt False f a (Const ())
+
+toCxt :: Bifunctor (Dual (NT (->))) (NT (->)) (NT (->)) f => Trm f a i -> Cxt h f a b i
+toCxt = unsafeCoerce
+
+instance Functor (NT (->)) (NT (->)) (f a) => Functor (NT (->)) (NT (->)) (Cxt h f a) where
+    map f = NT (\ case
+            Hole x -> Hole (nt f x)
+            Var  v -> Var v
+            In   t -> In (nt (map (map f :: NT (->) _ _)) t))
+
+instance (Bifunctor (NT (->)) (NT (->)) (NT (->)) f) =>
+         Functor (NT (->)) (NT (NT (->))) (Cxt h f) where
+    map f = NT (bimap f (id @(NT (->))))
+
+instance Bifunctor (NT (->)) (NT (->)) (NT (->)) f =>
+         Bifunctor (NT (->)) (NT (->)) (NT (->)) (Cxt h f) where
+    bimap f g = NT (\ case
+        Hole x -> Hole (nt g x)
+        Var  v -> Var (nt f v)
+        In   t -> In (nt (bimap f (bimap f g :: NT (->) _ _)) t))
+
+instance EqH f => EqH (Cxt h f) where
+    eqH (In s) (In t) = eqH s t
+    eqH (Hole x) (Hole y) = peq x y
+    eqH (Var u) (Var v) = peq u v
+    eqH _ _ = pure False
+
+instance (EqH f, PEq a) => PEq (Cxt h f Name a) where
+    peq = eqH
+
+instance EqH f => Eq (Term f i) where
+    Term x == Term y = evalFresh (eqH x y)
+
+instance (Bifunctor (Dual (NT (->))) (NT (->)) (NT (->)) f, ShowH f) => ShowH (Cxt h f) where
+    showH = \ case
+        In   t -> showH (bimap (Dual (id @(NT (->)))) (NT (Const . showH)) `nt` t)
+        Var  v -> pure $ show v
+        Hole x -> getConst x
+
+instance (Bifunctor (Dual (NT (->))) (NT (->)) (NT (->)) f, ShowH f) => Show (Term f i) where
+    show = evalFresh . showH . toCxt . unTerm
diff --git a/src/Prelude.hs b/src/Prelude.hs
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--- /dev/null
+++ b/src/Prelude.hs
@@ -0,0 +1,15 @@
+module Prelude (module A) where
+
+import Control.Categorical.Bifunctor as A
+import Control.Categorical.Functor as A
+import Control.Category as A
+import Control.Category.Dual as A
+import Data.Bool as A (Bool (..), bool)
+import Data.Char as A (Char)
+import Data.Either as A (Either (..), either)
+import Data.Functor.Const as A (Const (..))
+import Data.Functor.Identity as A (Identity (..))
+import Data.Maybe as A (Maybe (..), maybe)
+import Data.Proxy as A (Proxy (..))
+import Data.Void as A (Void)
+import Numeric.Natural as A (Natural)
diff --git a/test/Main.hs b/test/Main.hs
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--- /dev/null
+++ b/test/Main.hs
@@ -0,0 +1,8 @@
+module Main where
+
+import Test.SmallCheck
+import Test.Tasty
+import Test.Tasty.SmallCheck
+
+main :: IO ()
+main = defaultMain $ testGroup "" []