autoTC

.gitignore

@@ -1,3 +1,5 @@
 .stack-work/
 decidable.cabal
 *~
+.ghc.environment*
+dist-newstyle/

CHANGELOG.md

@@ -1,6 +1,15 @@
 Changelog
 =========
 
+Version 0.2.1.0
+---------------
+
+*August 24, 2019*
+
+<https://github.com/mstksg/decidable/releases/tag/v0.2.1.0>
+
+*   Add `autoTC` for convenient usage of `auto` with type constructors.
+
 Version 0.2.0.0
 ---------------
 

package.yaml

@@ -1,5 +1,5 @@
 name:                decidable
-version:             0.2.0.0
+version:             0.2.1.0
 github:              "mstksg/decidable"
 license:             BSD3
 author:              "Justin Le"

src/Data/Type/Predicate/Auto.hs

@@ -29,13 +29,14 @@
 module Data.Type.Predicate.Auto (
   -- * Automatically generate witnesses at compile-time
     Auto(..)
-  , AutoNot, autoNot
+  , autoTC
+  , AutoNot
+  , autoNot
+  , autoAny, autoNotAll
   , AutoProvable
   -- ** Helper classes
   , AutoElem(..)
   , AutoAll(..)
-  -- * Auto with help
-  , autoAny, autoNotAll
   ) where
 
 import           Data.Functor.Identity
@@ -84,6 +85,13 @@ class Auto (p :: Predicate k) (a :: k) where
     -- @
     auto :: p @@ a
 
+-- | A version of 'auto' that "just works" with type inference, if the
+-- predicate is a type constructor.
+--
+-- @since 0.2.1.0
+autoTC :: forall t a. Auto (TyPred t) a => t a
+autoTC = auto @_ @(TyPred t) @a
+
 instance SingI a => Auto Evident a where
     auto = sing