diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,21 @@
+# Dovetail
+
+Dovetail is a general-purpose PureScript interpreter written in Haskell.
+
+It has excellent support for interop with Haskell code via PureScript's foreign function interface, along with a high-level Haskell API for integrating such code.
+
+As such, it is possible to write low-level or domain-specific code in Haskell, and then to write the "glue code" in PureScript. In this way, Dovetail is a tool for reusing the frontend of the PureScript compiler (its syntax and type checker) to build domain specific languages in Haskell.
+
+## Getting Started
+
+To understand the library and how to use it, it is recommended that you read through the Haddock documentation, alongside the provided examples:
+
+- Hackage documentation
+  - [`dovetail` on Hackage](https://hackage.haskell.org/package/dovetail)
+  - [`dovetail-aeson` on Hackage](https://hackage.haskell.org/package/dovetail-aeson)
+  - [Haddocks on GitHub Pages](http://functorial.com/dovetail)
+- Examples:
+  - [JSON query language](https://github.com/paf31/dovetail/blob/main/examples/query-json/Main.hs)
+  - [Fake data generator](https://github.com/paf31/dovetail/blob/main/examples/fake-data/Main.hs)
+  
+You can build the code and examples in this repository using `stack build`, and run the test suite with `stack test`.
diff --git a/dovetail.cabal b/dovetail.cabal
--- a/dovetail.cabal
+++ b/dovetail.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 8e19e51ff69a860795e7b3909da11ef1e97bfc1266ab5075a42721d37c2f5f23
+-- hash: 9fd50996176509cb603dec378bf3364eb1637ccbf382d164e1e386e97d2e5da8
 
 name:           dovetail
-version:        0.1.0.0
+version:        0.1.1.0
 synopsis:       A PureScript interpreter with a Haskell FFI.
 description:    Dovetail is a general-purpose PureScript corefn interpreter with an FFI to Haskell. Please see the README on GitHub at <https://github.com/paf31/dovetail#readme>, or check out the examples directory, to learn how to use the library.
 category:       Language
@@ -19,6 +19,8 @@
 license:        BSD3
 license-file:   LICENSE
 build-type:     Simple
+extra-source-files:
+    README.md
 
 source-repository head
   type: git
diff --git a/src/Dovetail/Evaluate.hs b/src/Dovetail/Evaluate.hs
--- a/src/Dovetail/Evaluate.hs
+++ b/src/Dovetail/Evaluate.hs
@@ -333,7 +333,7 @@
   default fromValue :: (G.Generic a, ToObject m (G.Rep a)) => Value m -> EvalT m a
   fromValue = genericFromValue defaultObjectOptions
   
-instance MonadFix m => ToValue m (Value m) where
+instance (MonadFix m, m ~ m') => ToValue m (Value m') where
   toValue = id
   fromValue = pure
 
diff --git a/src/Dovetail/Prelude.hs b/src/Dovetail/Prelude.hs
--- a/src/Dovetail/Prelude.hs
+++ b/src/Dovetail/Prelude.hs
@@ -2,7 +2,9 @@
 {-# LANGUAGE FlexibleContexts    #-}
 {-# LANGUAGE GADTs               #-}
 {-# LANGUAGE ImportQualifiedPost #-}
+{-# LANGUAGE LambdaCase          #-}
 {-# LANGUAGE OverloadedStrings   #-}
+{-# LANGUAGE PatternSynonyms     #-}
 {-# LANGUAGE RankNTypes          #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeApplications    #-}
@@ -11,15 +13,18 @@
 module Dovetail.Prelude where
   
 import Control.Monad.Fix (MonadFix)
+import Control.Monad.Error.Class (catchError, throwError)
 import Data.Char (chr, ord)
 import Data.Text qualified as Text
 import Data.Vector qualified as Vector
-import Dovetail.Evaluate (ToValue, ToValueRHS)
-import Dovetail.FFI (FFI(..))
+import Dovetail.Evaluate (ToValue, ToValueRHS, toValue)
+import Dovetail.FFI (FFI(..), ForeignImport(..))
 import Dovetail.FFI.Builder (array, boolean, char, int, string, number, (~>))
 import Dovetail.FFI.Builder qualified as FFI
+import Dovetail.FFI.Internal (forAll, function)
 import Dovetail.Types
 import Language.PureScript qualified as P
+import Language.PureScript.Constants.Prim (pattern Partial)
 
 stdlib :: MonadFix m => [FFI m]
 stdlib = 
@@ -31,6 +36,7 @@
   , preludeInt
   , preludeBoolean
   , preludeDebug
+  , preludePartial
   ]
 
 prelude :: MonadFix m => FFI m
@@ -144,6 +150,40 @@
     FFI.foreignImport (P.Ident "crash")
       (\a -> string ~> a)
       (throwErrorWithContext . OtherError)
+      
+preludePartial :: forall m. MonadFix m => FFI m
+preludePartial = 
+  let partial ty =
+        P.ConstrainedType P.nullSourceAnn 
+          (P.Constraint P.nullSourceAnn Partial [] [] Nothing) 
+          ty
+   in FFI
+        { ffi_moduleName = P.ModuleName "Prelude.Partial"
+        , ffi_values = 
+            [ ForeignImport
+                { fv_name = P.Ident "unsafePartial"
+                , fv_type = 
+                    forAll \a -> partial a `function` a
+                , fv_value =
+                    toValue @m @((Value m -> EvalT m (Value m)) -> EvalT m (Value m)) 
+                      \f -> f (Object mempty)
+                }
+            , ForeignImport
+                { fv_name = P.Ident "fromPartial"
+                , fv_type = 
+                    forAll \a -> 
+                      a `function` (partial a `function` a)
+                , fv_value =
+                    toValue @m @(Value m -> (Value m -> EvalT m (Value m)) -> EvalT m (Value m)) 
+                      \def f -> do
+                        catchError (f (Object mempty)) \case
+                          EvaluationError { errorType = InexhaustivePatternMatch _ } ->
+                            pure def
+                          err ->
+                            throwError err
+                }
+            ]
+        }
 
 eqOps 
   :: (ToValue m a, ToValueRHS m (EvalT m a), Eq a)