diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,11 +1,15 @@
 # hs2ats
 
+## 0.5.0.1
+
+  * Remove `composition-prelude` dependency
+
 ## 0.5.0.0
 
   * Re-add `cpphs` dependency
 
 ## 0.4.0.0
-  
+
   * Stop depending on `cpphs`
 
 ## 0.3.0.4
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright Vanessa McHale (c) 2018
+Copyright Vanessa McHale (c) 2018-2019
 
 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 
diff --git a/hs2ats.cabal b/hs2ats.cabal
--- a/hs2ats.cabal
+++ b/hs2ats.cabal
@@ -1,46 +1,47 @@
-cabal-version: 1.18
-name: hs2ats
-version: 0.5.0.0
-license: BSD3
-license-file: LICENSE
-copyright: Copyright: (c) 2018 Vanessa McHale
-maintainer: vamchale@gmail.com
-author: Vanessa McHale
-synopsis: Create ATS types from Haskell types
+cabal-version:      1.18
+name:               hs2ats
+version:            0.5.0.1
+license:            BSD3
+license-file:       LICENSE
+copyright:          Copyright: (c) 2018-2019 Vanessa McHale
+maintainer:         vamchale@gmail.com
+author:             Vanessa McHale
+synopsis:           Create ATS types from Haskell types
 description:
     This package enables scanning Haskell source files for data types and then generating [ATS](http://www.ats-lang.org/) types from them.
-category: Language, Haskell, ATS
-build-type: Simple
+
+category:           Language, Haskell, ATS
+build-type:         Simple
 extra-source-files:
     test/data/*.hs
     test/data/*.out
-extra-doc-files: CHANGELOG.md
-                 README.md
 
+extra-doc-files:
+    CHANGELOG.md
+    README.md
+
 flag development
-    description:
-        Enable `-Werror`
-    default: False
-    manual: True
+    description: Enable `-Werror`
+    default:     False
+    manual:      True
 
 library
-    exposed-modules:
-        Language.ATS.Generate
-    hs-source-dirs: src
-    other-modules:
-        Language.ATS.Generate.Error
+    exposed-modules:  Language.ATS.Generate
+    hs-source-dirs:   src
+    other-modules:    Language.ATS.Generate.Error
     default-language: Haskell2010
-    other-extensions: DeriveAnyClass DeriveGeneric OverloadedStrings
-                      StandaloneDeriving PatternSynonyms
-    ghc-options: -Wall
+    other-extensions:
+        DeriveAnyClass DeriveGeneric OverloadedStrings StandaloneDeriving
+        PatternSynonyms
+
+    ghc-options:      -Wall
     build-depends:
         base >=4.7 && <5,
-        haskell-src-exts -any,
+        haskell-src-exts >=1.18.0,
         language-ats >=1.5.0.0,
         casing -any,
         microlens -any,
         ansi-wl-pprint -any,
-        composition-prelude -any,
         deepseq -any,
         cpphs -any
 
@@ -51,12 +52,14 @@
         ghc-options: -Wincomplete-uni-patterns -Wincomplete-record-updates
 
 executable hs2ats
-    main-is: Main.hs
-    hs-source-dirs: app
+    main-is:          Main.hs
+    hs-source-dirs:   app
     default-language: Haskell2010
-    other-extensions: DataKinds DeriveAnyClass DeriveGeneric
-                      OverloadedStrings TypeOperators
-    ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall
+    other-extensions:
+        DataKinds DeriveAnyClass DeriveGeneric OverloadedStrings
+        TypeOperators
+
+    ghc-options:      -threaded -rtsopts -with-rtsopts=-N -Wall
     build-depends:
         base -any,
         optparse-generic -any,
@@ -69,11 +72,11 @@
         ghc-options: -Wincomplete-uni-patterns -Wincomplete-record-updates
 
 test-suite hs2ats-test
-    type: exitcode-stdio-1.0
-    main-is: Spec.hs
-    hs-source-dirs: test
+    type:             exitcode-stdio-1.0
+    main-is:          Spec.hs
+    hs-source-dirs:   test
     default-language: Haskell2010
-    ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall
+    ghc-options:      -threaded -rtsopts -with-rtsopts=-N -Wall
     build-depends:
         base -any,
         hs2ats -any,
@@ -88,11 +91,11 @@
         ghc-options: -Wincomplete-uni-patterns -Wincomplete-record-updates
 
 benchmark hs2ats-bench
-    type: exitcode-stdio-1.0
-    main-is: Bench.hs
-    hs-source-dirs: bench
+    type:             exitcode-stdio-1.0
+    main-is:          Bench.hs
+    hs-source-dirs:   bench
     default-language: Haskell2010
-    ghc-options: -Wall
+    ghc-options:      -Wall
     build-depends:
         base -any,
         hs2ats -any,
diff --git a/src/Language/ATS/Generate.hs b/src/Language/ATS/Generate.hs
--- a/src/Language/ATS/Generate.hs
+++ b/src/Language/ATS/Generate.hs
@@ -10,7 +10,6 @@
     ) where
 
 import           Control.Arrow
-import           Data.Bool                    (bool)
 import           Data.Char                    (toUpper)
 import           Data.Either                  (lefts, rights)
 import           Data.Foldable
@@ -47,6 +46,7 @@
 
 -- should we allow user-defined string map?
 stringTypeConv :: String -> ErrM String
+stringTypeConv "Natural" = Right "intinfGte(0)" -- this is terrible but eh
 stringTypeConv "Integer" = Right "Intinf"
 stringTypeConv "String"  = Right "Strptr1"
 stringTypeConv "CString" = Right "Strptr1"
@@ -94,7 +94,7 @@
 conDeclToType (ConDecl _ n [])  = Right (toStringATS n, Nothing)
 conDeclToType (ConDecl _ n [t]) = (,) (toStringATS n) . Just <$> typeToType t
 conDeclToType (ConDecl _ n ts)  = (,) (toStringATS n) . Just . ATS.Tuple undefined <$> traverse typeToType ts
-conDeclToType (RecDecl _ _ []) = malformed "conDeclToType"
+conDeclToType (RecDecl _ _ [])  = malformed "conDeclToType"
 conDeclToType (RecDecl _ n fs)  = (,) (toStringATS n) . Just . AnonymousRecord undefined <$> traverse fieldDeclToType (NE.fromList (reverse fs))
 conDeclToType _                 = unsupported "conDeclToType"
 
@@ -130,8 +130,8 @@
 
 -- TODO if it derives functor, use +
 asATSType :: Decl a -> ErrM (Declaration b)
-asATSType (TypeDecl _ dh t) = ViewTypeDef undefined <$> (fst <$> asATSName dh) <*> (pruneATSNils . snd <$> asATSName dh) <*> typeToType t
-asATSType (DataDecl _ DataType{} _ _ [] _)    = malformed "asATSType"
+asATSType (TypeDecl _ dh t)                    = ViewTypeDef undefined <$> (fst <$> asATSName dh) <*> (pruneATSNils . snd <$> asATSName dh) <*> typeToType t
+asATSType (DataDecl _ DataType{} _ _ [] _)     = malformed "asATSType"
 asATSType (DataDecl _ NewType{} _ dh [qcd] _)  = ViewTypeDef undefined <$> (fst <$> asATSName dh) <*> (pruneATSNils . snd <$> asATSName dh) <*> qualConDeclToType qcd
 asATSType (DataDecl _ DataType{} _ dh [qcd] _) = ViewTypeDef undefined <$> (fst <$> asATSName dh) <*> (pruneATSNils . snd <$> asATSName dh) <*> qualConDeclToType qcd
 asATSType (DataDecl _ DataType{} _ dh qcds _)  = SumViewType <$> (fst <$> asATSName dh) <*> (pruneATSNils . snd <$> asATSName dh) <*> traverse qualConDeclToLeaf (NE.fromList (reverse qcds))
@@ -182,7 +182,9 @@
             -> Bool -- ^ Whether to use pre-process the Haskell source (use this if you use @{\#- LANGUAGE CPP \#-}@ anywhere)
             -> IO ()
 genATSTypes p p' withCPP = do
-    let proc = bool pure (process p) withCPP
+    let proc = if withCPP
+        then process p
+        else pure
     contents <- proc =<< readFile p
     let warnDo (x, es) = traverse_ displayErr es *> writeFile p' x
     either displayErr warnDo (generateATS p contents)
diff --git a/src/Language/ATS/Generate/Error.hs b/src/Language/ATS/Generate/Error.hs
--- a/src/Language/ATS/Generate/Error.hs
+++ b/src/Language/ATS/Generate/Error.hs
@@ -15,7 +15,6 @@
                                    , malformed
                                    ) where
 
-import           Control.Composition
 import           Control.DeepSeq              (NFData)
 import           GHC.Generics                 (Generic)
 import           Language.Haskell.Exts        hiding (Pretty, loc)
@@ -30,7 +29,7 @@
 type ErrM a = Either GenerateError a
 
 syntaxError :: SrcLoc -> String -> ErrM a
-syntaxError = Left .* HaskellSyntaxError
+syntaxError = (Left .) . HaskellSyntaxError
 
 unsupported :: String -> ErrM a
 unsupported = Left . Unsupported