401b44a · typeable/servant

git.iko.soy/typeable/servant

Make default ToSample instances productive

The default Generics-based ToSample instance now uses Omega type to productively produce distinct samples. The previous version was based on lists and hence left-recursive. This means that with previous versions the default toSamples for [Bool] would return an infinite list like this: [[],[False],[False,False],[False,False,False],... As you can see it would never produce a list with True in it. Omega handles this and produces a more diverse output: [[],[False],[False,False],[True],... This is still not the best possible case, but to do better we need to use Omega not only in GToSample, but in ToSample as well since GToSample uses ToSample instances recursively.

commit401b44ac1b3c8f3240400f2f56a0e143689af13e authorNickolay Kudasov <nickolay.kudasov@gmail.com> dateSat 19 Sep 2015, 01:25 (11 years ago) parentc769800

3 files changed+7−4

compare with master

unifiedsplit

servant-docs/servant-docs.cabal+1 servant-docs/src/Servant/Docs/Internal.hs+5−4 stack.yaml+1

servant-docs/servant-docs.cabal+1

@@ -42,6 +42,7 @@ library

4242 , string-conversions

4343 , text

4444 , unordered-containers

45+ , control-monad-omega == 0.3.*

4546 hs-source-dirs: src

4647 default-language: Haskell2010

4748 ghc-options: -Wall

servant-docs/src/Servant/Docs/Internal.hs+5−4

@@ -23,6 +23,7 @@ module Servant.Docs.Internal where

2323import Control.Applicative

2424import Control.Arrow (second)

2525import Control.Lens hiding (List, to, from)

26+import qualified Control.Monad.Omega as Omega

2627import Data.ByteString.Conversion (ToByteString, toByteString)

2728import Data.ByteString.Lazy.Char8 (ByteString)

2829import qualified Data.CaseInsensitive as CI

@@ -394,12 +395,12 @@ defaultSample :: forall a b. (Generic a, Generic b, GToSample (Rep a) (Rep b)) =

394395defaultSample _ = to <$> gtoSample (Proxy :: Proxy (Rep a))

395396

396397defaultSamples :: forall a b. (Generic a, Generic b, GToSample (Rep a) (Rep b)) => Proxy a -> [(Text, b)]

397−defaultSamples _ = second to <$> gtoSamples (Proxy :: Proxy (Rep a))

398+defaultSamples _ = Omega.runOmega $ second to <$> gtoSamples (Proxy :: Proxy (Rep a))

398399

399400class GToSample t s where

400401 gtoSample :: proxy t -> Maybe (s x)

401− gtoSample _ = snd <$> listToMaybe (gtoSamples (Proxy :: Proxy t))

402− gtoSamples :: proxy t -> [(Text, s x)]

402+ gtoSample _ = snd <$> listToMaybe (Omega.runOmega (gtoSamples (Proxy :: Proxy t)))

403+ gtoSamples :: proxy t -> Omega.Omega (Text, s x)

403404 gtoSamples _ = maybe empty (pure . ("",)) (gtoSample (Proxy :: Proxy t))

404405

405406instance GToSample U1 U1 where

@@ -426,7 +427,7 @@ instance (GToSample p p', GToSample q q') => GToSample (p :+: q) (p' :+: q') whe

426427

427428instance ToSample a b => GToSample (K1 i a) (K1 i b) where

428429 gtoSample _ = K1 <$> toSample (Proxy :: Proxy a)

429− gtoSamples _ = second K1 <$> toSamples (Proxy :: Proxy a)

430+ gtoSamples _ = second K1 <$> Omega.each (toSamples (Proxy :: Proxy a))

430431

431432instance (GToSample f g) => GToSample (M1 i a f) (M1 i a g) where

432433 gtoSample _ = M1 <$> gtoSample (Proxy :: Proxy f)

stack.yaml+1

@@ -14,4 +14,5 @@ packages:

1414- servant-server/

1515extra-deps:

1616- engine-io-wai-1.0.2

17+- control-monad-omega-0.3.1

1718resolver: nightly-2015-09-10