Docx Reader: Get rid of Modifiable typeclass.

The docx reader used to use a Modifiable typeclass to combine both Blocks and Inlines. But all the work was in the inlines. So most of the generality was wasted, at the expense of making the code harder to understand. This gets rid of the generality, and adds functions for Blocks and Inlines. It should be a bit easier to work with going forward.
author: Jesse Rosenthal <jrosenthal@jhu.edu> 2016-02-26 08:47:26 -0500
committer: Jesse Rosenthal <jrosenthal@jhu.edu> 2016-02-26 08:57:53 -0500
commit: a7a0b452a5f3ac3e1897c1f56758731f82a12f2f (patch)
tree: 8571bd4016a02177c4a68d1b2a9d743a96b18522 /src/Text/Pandoc/Readers/Docx
parent: 38bd4162fefb35a33c22dd939a594262fbdc8a46 (diff)
download: pandoc-a7a0b452a5f3ac3e1897c1f56758731f82a12f2f.tar.gz
2 files changed, 154 insertions, 183 deletions
diff --git a/src/Text/Pandoc/Readers/Docx/Combine.hs b/src/Text/Pandoc/Readers/Docx/Combine.hs
new file mode 100644
index 000000000..39e0df825
--- /dev/null
+++ b/src/Text/Pandoc/Readers/Docx/Combine.hs
@@ -0,0 +1,154 @@
+{-# LANGUAGE TypeSynonymInstances, FlexibleInstances,
+    PatternGuards #-}
+
+module Text.Pandoc.Readers.Docx.Combine ( smushInlines
+                                        , smushBlocks
+                                        )
+       where
+
+import Text.Pandoc.Builder
+import Data.List
+import Data.Sequence (ViewR(..), ViewL(..), viewl, viewr, (><), (|>))
+import qualified Data.Sequence as Seq (null)
+
+data Modifier a = Modifier (a -> a)
+                | AttrModifier (Attr -> a -> a) Attr
+                | NullModifier
+
+spaceOutInlinesL :: Inlines -> (Inlines, Inlines)
+spaceOutInlinesL ms = (l, stackInlines fs (m' <> r))
+  where (l, m, r) = spaceOutInlines ms
+        (fs, m')  = unstackInlines m
+
+spaceOutInlinesR :: Inlines -> (Inlines, Inlines)
+spaceOutInlinesR ms = (stackInlines fs (l <> m'), r)
+  where (l, m, r) = spaceOutInlines ms
+        (fs, m')  = unstackInlines m
+
+spaceOutInlines :: Inlines -> (Inlines, Inlines, Inlines)
+spaceOutInlines ils =
+  let (fs, ils') = unstackInlines ils
+      contents = unMany ils'
+      left  = case viewl contents of
+        (Space :< _) -> space
+        _            -> mempty
+      right = case viewr contents of
+        (_ :> Space) -> space
+        _            -> mempty in
+  (left, (stackInlines fs $ trimInlines . Many $ contents), right)
+
+stackInlines :: [Modifier Inlines] -> Inlines -> Inlines
+stackInlines [] ms = ms
+stackInlines (NullModifier : fs) ms = stackInlines fs ms
+stackInlines ((Modifier f) : fs) ms =
+  if isEmpty ms
+  then stackInlines fs ms
+  else f $ stackInlines fs ms
+stackInlines ((AttrModifier f attr) : fs) ms = f attr $ stackInlines fs ms
+
+unstackInlines :: Inlines -> ([Modifier Inlines], Inlines)
+unstackInlines ms = case ilModifier ms of
+  NullModifier -> ([], ms)
+  _            -> (f : fs, ms') where
+    f = ilModifier ms
+    (fs, ms') = unstackInlines $ ilInnards ms
+
+ilModifier :: Inlines -> Modifier Inlines
+ilModifier ils = case viewl (unMany ils) of
+  (x :< xs) | Seq.null xs -> case x of
+    (Emph _)        -> Modifier emph
+    (Strong _)      -> Modifier strong
+    (SmallCaps _)   -> Modifier smallcaps
+    (Strikeout _)   -> Modifier strikeout
+    (Superscript _) -> Modifier superscript
+    (Subscript _)   -> Modifier subscript
+    (Link attr _ tgt) -> Modifier $ linkWith attr (fst tgt) (snd tgt)
+    (Span attr _)   -> AttrModifier spanWith attr
+    _               -> NullModifier
+  _ -> NullModifier
+
+ilInnards :: Inlines -> Inlines
+ilInnards ils = case viewl (unMany ils) of
+  (x :< xs) | Seq.null xs -> case x of
+    (Emph lst)        -> fromList lst
+    (Strong lst)      -> fromList lst
+    (SmallCaps lst)   -> fromList lst
+    (Strikeout lst)   -> fromList lst
+    (Superscript lst) -> fromList lst
+    (Subscript lst)   -> fromList lst
+    (Link _ lst _)    -> fromList lst
+    (Span _ lst)      -> fromList lst
+    _        -> ils
+  _          -> ils
+
+inlinesL :: Inlines -> (Inlines, Inlines)
+inlinesL ils = case viewl $ unMany ils of
+  (s :< sq) -> (singleton s, Many sq)
+  _          -> (mempty, ils)
+
+inlinesR :: Inlines -> (Inlines, Inlines)
+inlinesR ils = case viewr $ unMany ils of
+  (sq :> s) -> (Many sq, singleton s)
+  _          -> (ils, mempty)
+
+combineInlines :: Inlines -> Inlines -> Inlines
+combineInlines x y =
+  let (xs', x') = inlinesR x
+      (y', ys') = inlinesL y
+  in
+   xs' <> (combineSingletonInlines x' y') <> ys'
+
+combineSingletonInlines :: Inlines -> Inlines -> Inlines
+combineSingletonInlines x y =
+  let (xfs, xs) = unstackInlines x
+      (yfs, ys) = unstackInlines y
+      shared = xfs `intersect` yfs
+      x_remaining = xfs \\ shared
+      y_remaining = yfs \\ shared
+      x_rem_attr = filter isAttrModifier x_remaining
+      y_rem_attr = filter isAttrModifier y_remaining
+  in
+   case null shared of
+     True | isEmpty xs && isEmpty ys ->
+            stackInlines (x_rem_attr ++ y_rem_attr) mempty
+          | isEmpty xs ->
+            let (sp, y') = spaceOutInlinesL y in
+            (stackInlines x_rem_attr mempty) <> sp <> y'
+          | isEmpty ys ->
+            let (x', sp) = spaceOutInlinesR x in
+            x' <> sp <> (stackInlines y_rem_attr mempty)
+          | otherwise ->
+              let (x', xsp) = spaceOutInlinesR x
+                  (ysp, y') = spaceOutInlinesL y
+              in
+               x' <> xsp <> ysp <> y'
+     False -> stackInlines shared $
+              combineInlines
+              (stackInlines x_remaining xs)
+              (stackInlines y_remaining ys)
+
+combineBlocks :: Blocks -> Blocks -> Blocks
+combineBlocks bs cs
+  | bs' :> (BlockQuote bs'') <- viewr (unMany bs)
+  , (BlockQuote cs'') :< cs' <- viewl (unMany cs) =
+      Many $ (bs' |> (BlockQuote (bs'' <> cs''))) >< cs'
+combineBlocks bs cs = bs <> cs
+
+instance (Monoid a, Eq a) => Eq (Modifier a) where
+  (Modifier f) == (Modifier g) = (f mempty == g mempty)
+  (AttrModifier f attr) == (AttrModifier g attr') = (f attr mempty == g attr' mempty)
+  (NullModifier) == (NullModifier) = True
+  _ == _ = False
+
+isEmpty :: (Monoid a, Eq a) => a -> Bool
+isEmpty x = x == mempty
+
+isAttrModifier :: Modifier a -> Bool
+isAttrModifier (AttrModifier _ _) = True
+isAttrModifier _                  = False
+
+smushInlines :: [Inlines] -> Inlines
+smushInlines xs = foldl combineInlines mempty xs
+
+smushBlocks :: [Blocks] -> Blocks
+smushBlocks xs = foldl combineBlocks mempty xs
diff --git a/src/Text/Pandoc/Readers/Docx/Reducible.hs b/src/Text/Pandoc/Readers/Docx/Reducible.hs
deleted file mode 100644
index e6de2d474..000000000
--- a/src/Text/Pandoc/Readers/Docx/Reducible.hs
+++ /dev/null
@@ -1,183 +0,0 @@
-{-# LANGUAGE TypeSynonymInstances, FlexibleInstances,
-    PatternGuards #-}
-
-module Text.Pandoc.Readers.Docx.Reducible ( concatReduce
-                                          , (<+>)
-                                          )
-       where
-
-
-import Text.Pandoc.Builder
-import Data.List
-import Data.Sequence (ViewR(..), ViewL(..), viewl, viewr)
-import qualified Data.Sequence as Seq (null)
-
-data Modifier a = Modifier (a -> a)
-                | AttrModifier (Attr -> a -> a) Attr
-                | NullModifier
-
-class (Eq a) => Modifiable a where
-  modifier :: a -> Modifier a
-  innards :: a -> a
-  getL    :: a -> (a, a)
-  getR    :: a -> (a, a)
-  spaceOut :: a -> (a, a, a)
-
-spaceOutL :: (Monoid a, Modifiable a) => a -> (a, a)
-spaceOutL ms = (l, stack fs (m' <> r))
-  where (l, m, r) = spaceOut ms
-        (fs, m')  = unstack m
-
-spaceOutR :: (Monoid a, Modifiable a) => a -> (a, a)
-spaceOutR ms = (stack fs (l <> m'), r)
-  where (l, m, r) = spaceOut ms
-        (fs, m')  = unstack m
-
-instance (Monoid a, Show a) => Show (Modifier a) where
-  show (Modifier f) = show $ f mempty
-  show (AttrModifier f attr) = show $ f attr mempty
-  show (NullModifier) = "NullModifier"
-
-instance (Monoid a, Eq a) => Eq (Modifier a) where
-  (Modifier f) == (Modifier g) = (f mempty == g mempty)
-  (AttrModifier f attr) == (AttrModifier g attr') = (f attr mempty == g attr' mempty)
-  (NullModifier) == (NullModifier) = True
-  _ == _ = False
-
-instance Modifiable Inlines where
-  modifier ils = case viewl (unMany ils) of
-    (x :< xs) | Seq.null xs -> case x of
-      (Emph _)        -> Modifier emph
-      (Strong _)      -> Modifier strong
-      (SmallCaps _)   -> Modifier smallcaps
-      (Strikeout _)   -> Modifier strikeout
-      (Superscript _) -> Modifier superscript
-      (Subscript _)   -> Modifier subscript
-      (Link attr _ tgt) -> Modifier $ linkWith attr (fst tgt) (snd tgt)
-      (Span attr _)   -> AttrModifier spanWith attr
-      _               -> NullModifier
-    _ -> NullModifier
-
-  innards ils = case viewl (unMany ils) of
-    (x :< xs) | Seq.null xs -> case x of
-      (Emph lst)        -> fromList lst
-      (Strong lst)      -> fromList lst
-      (SmallCaps lst)   -> fromList lst
-      (Strikeout lst)   -> fromList lst
-      (Superscript lst) -> fromList lst
-      (Subscript lst)   -> fromList lst
-      (Link _ lst _)    -> fromList lst
-      (Span _ lst)      -> fromList lst
-      _        -> ils
-    _          -> ils
-
-  getL ils = case viewl $ unMany ils of
-    (s :< sq) -> (singleton s, Many sq)
-    _          -> (mempty, ils)
-
-  getR ils = case viewr $ unMany ils of
-    (sq :> s) -> (Many sq, singleton s)
-    _          -> (ils, mempty)
-
-  spaceOut ils =
-    let (fs, ils') = unstack ils
-        contents = unMany ils'
-        left  = case viewl contents of
-          (Space :< _) -> space
-          _            -> mempty
-        right = case viewr contents of
-          (_ :> Space) -> space
-          _            -> mempty in
-    (left, (stack fs $ trimInlines .Many $ contents), right)
-
-instance Modifiable Blocks where
-  modifier blks = case viewl (unMany blks) of
-    (x :< xs) | Seq.null xs -> case x of
-      (BlockQuote _) -> Modifier blockQuote
-      -- (Div attr _)   -> AttrModifier divWith attr
-      _               -> NullModifier
-    _ -> NullModifier
-
-  innards blks = case viewl (unMany blks) of
-    (x :< xs) | Seq.null xs -> case x of
-      (BlockQuote lst) -> fromList lst
-      -- (Div attr lst)   -> fromList lst
-      _        -> blks
-    _          -> blks
-
-  spaceOut blks = (mempty, blks, mempty)
-
-  getL ils = case viewl $ unMany ils of
-    (s :< sq) -> (singleton s, Many sq)
-    _          -> (mempty, ils)
-
-  getR ils = case viewr $ unMany ils of
-    (sq :> s) -> (Many sq, singleton s)
-    _          -> (ils, mempty)
-
-
-unstack :: (Modifiable a) => a -> ([Modifier a], a)
-unstack ms = case modifier ms of
-  NullModifier -> ([], ms)
-  _            -> (f : fs, ms') where
-    f = modifier ms
-    (fs, ms') = unstack $ innards ms
-
-stack :: (Monoid a, Modifiable a) => [Modifier a] -> a -> a
-stack [] ms = ms
-stack (NullModifier : fs) ms = stack fs ms
-stack ((Modifier f) : fs) ms =
-  if isEmpty ms
-  then stack fs ms
-  else f $ stack fs ms
-stack ((AttrModifier f attr) : fs) ms = f attr $ stack fs ms
-
-isEmpty :: (Monoid a, Eq a) => a -> Bool
-isEmpty x = x == mempty
-
-
-combine :: (Monoid a, Modifiable a, Eq a) => a -> a -> a
-combine x y =
-  let (xs', x') = getR x
-      (y', ys') = getL y
-  in
-   xs' <> (combineSingleton x' y') <> ys'
-
-isAttrModifier :: Modifier a -> Bool
-isAttrModifier (AttrModifier _ _) = True
-isAttrModifier _                  = False
-
-combineSingleton :: (Monoid a, Modifiable a, Eq a) => a -> a -> a
-combineSingleton x y =
-  let (xfs, xs) = unstack x
-      (yfs, ys) = unstack y
-      shared = xfs `intersect` yfs
-      x_remaining = xfs \\ shared
-      y_remaining = yfs \\ shared
-      x_rem_attr = filter isAttrModifier x_remaining
-      y_rem_attr = filter isAttrModifier y_remaining
-  in
-   case null shared of
-     True | isEmpty xs && isEmpty ys ->
-            stack (x_rem_attr ++ y_rem_attr) mempty
-          | isEmpty xs ->
-            let (sp, y') = spaceOutL y in
-            (stack x_rem_attr mempty) <> sp <> y'
-          | isEmpty ys ->
-            let (x', sp) = spaceOutR x in
-            x' <> sp <> (stack y_rem_attr mempty)
-          | otherwise ->
-              let (x', xsp) = spaceOutR x
-                  (ysp, y') = spaceOutL y
-              in
-               x' <> xsp <> ysp <> y'
-     False -> stack shared $
-              combine
-              (stack x_remaining xs)
-              (stack y_remaining ys)
-
-(<+>) :: (Monoid a, Modifiable a, Eq a) => a -> a -> a
-x <+> y = combine x y
-
-concatReduce :: (Monoid a, Modifiable a) => [a] -> a
-concatReduce xs = foldl combine mempty xs
author	Jesse Rosenthal <jrosenthal@jhu.edu>	2016-02-26 08:47:26 -0500
committer	Jesse Rosenthal <jrosenthal@jhu.edu>	2016-02-26 08:57:53 -0500
commit	a7a0b452a5f3ac3e1897c1f56758731f82a12f2f (patch)
tree	8571bd4016a02177c4a68d1b2a9d743a96b18522 /src/Text/Pandoc/Readers/Docx
parent	38bd4162fefb35a33c22dd939a594262fbdc8a46 (diff)
download	pandoc-a7a0b452a5f3ac3e1897c1f56758731f82a12f2f.tar.gz