Now with a few Hedgehog examples

package.yaml

@@ -26,6 +26,7 @@ dependencies:
 - data-diverse
 - containers
 - unordered-containers
+- hedgehog
 
 default-extensions:
   - NoImplicitPrelude
@@ -63,7 +64,6 @@ default-extensions:
   - TypeFamilies
   - TypeFamilyDependencies
   - TypeOperators
-  - UndecidableInstances
 
 library:
   source-dirs: src

src/HedgehogExample.hs

@@ -0,0 +1,77 @@
+{-# LANGUAGE ApplicativeDo #-}
+module HedgehogExample where
+
+import Hedgehog
+import Hedgehog.Gen as Gen
+import Hedgehog.Range as Range
+import Universum
+import V2
+import Data.Diverse
+
+newtype Name = Name Text
+newtype Address = Address Text
+newtype Email = Email Text
+
+data Person = Person
+  { _name :: Name
+  , _address :: Address
+  , _email :: Email
+  }
+
+data Company = Company
+  { _employees :: [Person]
+  , _ceo :: Person }
+
+instance MonadGen m => DefaultRecipe Identity (m Name) where
+  type DefaultRecipeDeps Identity (m Name) = '[]
+  def = pureRecipe $ do
+    name <- text (linear 3 20) unicode
+    pure $ Name name
+
+instance MonadGen m => DefaultRecipe Identity (m Address) where
+  type DefaultRecipeDeps Identity (m Address) = '[]
+  def = pureRecipe $ do
+    name <- text (linear 3 20) unicode
+    pure $ Address name
+
+instance MonadGen m => DefaultRecipe Identity (m Email) where
+  type DefaultRecipeDeps Identity (m Email) = '[]
+  def = pureRecipe $ do
+    user <- text (linear 3 20) ascii
+    host <- text (linear 3 10) ascii
+    pure $ Email $ (user <> "@" <> host)
+
+instance MonadGen m => DefaultRecipe Identity (m Person) where
+  type DefaultRecipeDeps Identity (m Person) = '[m Name, m Address, m Email]
+  def = Recipe $ \deps -> pure $ do
+    name <- grab deps
+    address <- grab deps
+    email <- grab deps
+    pure $ Person name address email
+
+instance MonadGen m => DefaultRecipe Identity (m Company) where
+  type DefaultRecipeDeps Identity (m Company) = '[m Person]
+  def = Recipe $ \deps -> pure $ do
+    ceo <- grab deps
+    employees <- Gen.list (linear 3 10) (grab deps)
+    pure $ Company employees ceo
+
+regularGen :: MonadGen m => m Company
+regularGen = runIdentity $ finish nil
+
+largeCompanyGen' :: forall (m :: * -> *). MonadGen m => Recipe Identity (m Company) '[m Person]
+largeCompanyGen' = Recipe $ \deps -> pure $ do
+  ceo <- grab deps
+  employees <- Gen.list (linear 100 1000) (grab deps)
+  pure $ Company employees ceo
+
+largeCompanyGen :: forall m. MonadGen m => (m Company)
+largeCompanyGen = runIdentity $ finish (largeCompanyGen' @m ./ nil) -- TODO why is this annotation required?
+
+fixedEmailGen' :: forall m. MonadGen m => Text -> Recipe Identity (m Email) '[]
+fixedEmailGen' domain = pureRecipe $ do
+  user <- text (linear 3 20) ascii
+  pure $ Email $ (user <> "@" <> domain)
+
+fixedEmailGen :: forall m. MonadGen m => (m Company)
+fixedEmailGen = runIdentity $ finish (fixedEmailGen' @m "company.com" ./ nil)

src/TestData.hs

@@ -0,0 +1,42 @@
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE DataKinds #-}
+
+module TestData where
+
+import V2
+import Universum hiding (Nat)
+import Data.Diverse
+
+forceResult :: Proxy a -> Proxy a -> Proxy a
+forceResult _ _ = Proxy
+
+data M0 = M0 M1 M3
+data M1 = M1 M2 M3
+newtype M2 = M2 ()
+newtype M3 = M3 M4
+newtype M4 = M4 ()
+newtype M5 = M5 M0
+
+instance DefaultRecipe Identity M0 where
+  type DefaultRecipeDeps Identity M0 = '[M1, M3]
+  def = Recipe $ \deps -> pure $ M0 (grab deps) (grab deps)
+
+instance DefaultRecipe Identity M1 where
+  type DefaultRecipeDeps Identity M1 = '[M2, M3]
+  def = Recipe $ \deps -> pure $ M1 (grab deps) (grab deps)
+
+instance DefaultRecipe Identity M2 where
+  type DefaultRecipeDeps Identity M2 = '[]
+  def = Recipe $ \deps -> pure $ M2 ()
+
+instance DefaultRecipe Identity M3 where
+  type DefaultRecipeDeps Identity M3 = '[M4]
+  def = Recipe $ \deps -> pure $ M3 (grab deps)
+
+instance DefaultRecipe Identity M4 where
+  type DefaultRecipeDeps Identity M4 = '[]
+  def = Recipe $ \deps -> pure $ M4 ()
+
+instance DefaultRecipe Identity M5 where
+  type DefaultRecipeDeps Identity M5 = '[M0]
+  def = Recipe $ \deps -> pure $ M5 (grab deps)

src/V2.hs

@@ -15,7 +15,7 @@ import Unsafe.Coerce
 import Numbers
 -- import GHC.TypeLits as Lits
 
-pureRecipe :: Applicative effect => target -> Recipe effect target $ empty
+pureRecipe :: Applicative effect => target -> Recipe effect target '[]
 pureRecipe target = Recipe $ \_ -> pure target
 
 --  - first calculate the required storage for state via type family