From fcee1c0c8c9c8ddce45f26c566b5eb8527e9dd0b Mon Sep 17 00:00:00 2001
From: Yann Herklotz <git@yannherklotz.com>
Date: Sun, 28 May 2023 01:56:59 +0100
Subject: Add type annotations to query function

---
 src/Zettel/Types.hs | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/src/Zettel/Types.hs b/src/Zettel/Types.hs
index 2b8d23d..580052b 100644
--- a/src/Zettel/Types.hs
+++ b/src/Zettel/Types.hs
@@ -1,9 +1,9 @@
 {-# LANGUAGE DerivingVia #-}
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE StandaloneDeriving #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE StandaloneDeriving #-}
 
 module Zettel.Types
   ( Combine (..),
@@ -18,8 +18,8 @@ module Zettel.Types
 where
 
 import Text.Pandoc.Builder (ToMetaValue (..))
-import Text.Pandoc.Definition (Inline (..), Pandoc (..), Block (..), Row (..), Caption (..), TableHead(..), TableBody(..), TableFoot(..), Meta(..), MetaValue(..))
-import Text.Pandoc.Walk (Walkable(..))
+import Text.Pandoc.Definition (Block (..), Caption (..), Inline (..), Meta (..), MetaValue (..), Pandoc (..), Row (..), TableBody (..), TableFoot (..), TableHead (..))
+import Text.Pandoc.Walk (Walkable (..))
 
 class Combine a where
   cappend :: a -> a -> a
@@ -97,12 +97,17 @@ instance Combine Zettel where
 
   cempty = Zettel cempty cempty cempty cempty cempty
 
-walkMZettel :: (Walkable a Pandoc, Monad m, Applicative m, Functor m)
-            => (a -> m a) -> Zettel -> m Zettel
+walkMZettel ::
+  (Walkable a Pandoc, Monad m, Applicative m, Functor m) =>
+  (a -> m a) ->
+  Zettel ->
+  m Zettel
 walkMZettel f b = do
   res <- walkM f (zettelBody b)
   return b {zettelBody = res}
 
+queryZettel ::
+  (Walkable a Pandoc, Monoid c) => (a -> c) -> Zettel -> c
 queryZettel f = query f . zettelBody
 
 instance Walkable Block Zettel where
@@ -139,13 +144,19 @@ data ZettelGraph = ZettelGraph
   }
   deriving (Show, Eq)
 
-walkMZettelGraph :: (Walkable a Pandoc, Walkable a Zettel, Monad m, Applicative m, Functor m)
-            => (a -> m a) -> ZettelGraph -> m ZettelGraph
+walkMZettelGraph ::
+  (Walkable a Pandoc, Walkable a Zettel, Monad m, Applicative m, Functor m) =>
+  (a -> m a) ->
+  ZettelGraph ->
+  m ZettelGraph
 walkMZettelGraph f b = do
   res <- traverse (walkM f) (unZettelGraph b)
   newBib <- traverse (walkM f) (zettelGraphBib b)
   return $ ZettelGraph res newBib
 
+queryZettelGraph
+  :: (Monoid a1, Walkable a2 Zettel, Walkable a2 Pandoc) =>
+     (a2 -> a1) -> ZettelGraph -> a1
 queryZettelGraph f g = query f (unZettelGraph g) <> maybe mempty (query f) (zettelGraphBib g)
 
 instance Walkable Block ZettelGraph where
@@ -176,4 +187,4 @@ instance Walkable [Inline] ZettelGraph where
   walkM = walkMZettelGraph
   query = queryZettelGraph
 
---instance Walkable ZettelGraph
+-- instance Walkable ZettelGraph
-- 
cgit