From 0975c99f8e8fc2f33c968daa8968444bb0c026c5 Mon Sep 17 00:00:00 2001
From: Jaro <jaro@argonaut-constellation.org>
Date: Fri, 16 Jun 2023 20:42:39 +0200
Subject: [PATCH] Refactor lineNumbers into a common module.

---
 balkon.cabal                                  |  1 +
 .../ParagraphLayout/Internal/LineNumbers.hs   | 23 +++++++++++++++++++
 .../ParagraphLayout/Internal/Paginable.hs     |  3 ++-
 .../ParagraphLayout/Internal/ParagraphLine.hs | 16 ++-----------
 .../Internal/Plain/ParagraphLayout.hs         |  4 ++++
 .../Internal/Rich/ParagraphLayout.hs          |  4 ++++
 6 files changed, 36 insertions(+), 15 deletions(-)
 create mode 100644 src/Data/Text/ParagraphLayout/Internal/LineNumbers.hs

diff --git a/balkon.cabal b/balkon.cabal
index 375ea59..77b9c07 100644
--- a/balkon.cabal
+++ b/balkon.cabal
@@ -137,6 +137,7 @@ library balkon-internal
     -- Modules used purely internally and not in any tests.
     other-modules:
         Data.Text.ParagraphLayout.Internal.Layout,
+        Data.Text.ParagraphLayout.Internal.LineNumbers,
         Data.Text.ParagraphLayout.Internal.ParagraphExtents,
         Data.Text.ParagraphLayout.Internal.ParagraphLine,
         Data.Text.ParagraphLayout.Internal.ProtoFragment,
diff --git a/src/Data/Text/ParagraphLayout/Internal/LineNumbers.hs b/src/Data/Text/ParagraphLayout/Internal/LineNumbers.hs
new file mode 100644
index 0000000..e0f2750
--- /dev/null
+++ b/src/Data/Text/ParagraphLayout/Internal/LineNumbers.hs
@@ -0,0 +1,23 @@
+module Data.Text.ParagraphLayout.Internal.LineNumbers
+    ( LineNumbers
+    , lineNumbers
+    , lineNumbersWithDuplication
+    )
+where
+
+import qualified Data.List.NonEmpty as NonEmpty
+
+-- | Data types that contain numbered lines.
+class LineNumbers ml where
+
+    -- | A list of all line numbers in ascending order,
+    -- with possible duplicates.
+    lineNumbersWithDuplication :: ml -> [Int]
+
+-- | A list of all unique line numbers, in ascending order.
+lineNumbers :: (LineNumbers ml) => ml -> [Int]
+lineNumbers ml = dedupe $ lineNumbersWithDuplication ml
+
+-- | Remove duplicates from a sorted list.
+dedupe :: Eq a => [a] -> [a]
+dedupe xs = map NonEmpty.head $ NonEmpty.group xs
diff --git a/src/Data/Text/ParagraphLayout/Internal/Paginable.hs b/src/Data/Text/ParagraphLayout/Internal/Paginable.hs
index 312782b..1b805b8 100644
--- a/src/Data/Text/ParagraphLayout/Internal/Paginable.hs
+++ b/src/Data/Text/ParagraphLayout/Internal/Paginable.hs
@@ -8,6 +8,7 @@ where
 
 import Data.Int (Int32)
 
+import Data.Text.ParagraphLayout.Internal.LineNumbers
 import Data.Text.ParagraphLayout.Internal.LinePagination
 import Data.Text.ParagraphLayout.Internal.ParagraphLine
 import qualified Data.Text.ParagraphLayout.Internal.Plain.ParagraphLayout
@@ -86,7 +87,7 @@ instance Paginable (Plain.ParagraphLayout d) where
 instance Paginable (Rich.ParagraphLayout d) where
     paginate = paginateLayout
 
-paginateLayout :: (Line a, GenericLayout a) =>
+paginateLayout :: (Line a, LineNumbers a, GenericLayout a) =>
    PageOptions -> a -> (PageContinuity, a, Maybe a)
 paginateLayout opts pl =
     case paginate opts (cutLines pl) of
diff --git a/src/Data/Text/ParagraphLayout/Internal/ParagraphLine.hs b/src/Data/Text/ParagraphLayout/Internal/ParagraphLine.hs
index 4c0aff8..4966eae 100644
--- a/src/Data/Text/ParagraphLayout/Internal/ParagraphLine.hs
+++ b/src/Data/Text/ParagraphLayout/Internal/ParagraphLine.hs
@@ -7,9 +7,9 @@ module Data.Text.ParagraphLayout.Internal.ParagraphLine
 where
 
 import Data.Int (Int32)
-import qualified Data.List.NonEmpty as NonEmpty
 
 import Data.Text.ParagraphLayout.Internal.Fragment
+import Data.Text.ParagraphLayout.Internal.LineNumbers
 import qualified Data.Text.ParagraphLayout.Internal.Plain.ParagraphLayout as P
 import qualified Data.Text.ParagraphLayout.Internal.Rich.ParagraphLayout as R
 import Data.Text.ParagraphLayout.Internal.Rect
@@ -25,9 +25,6 @@ class GenericLayout pl where
     -- | Actual distance between the paragraph origin and the nearest fragment.
     topDistance :: pl -> Int32
 
-    -- | A list of all unique line numbers that have laid out content.
-    lineNumbers :: pl -> [Int]
-
     -- | Keep only fragments with the given line number.
     limitFragments :: Int -> pl -> pl
 
@@ -42,7 +39,6 @@ instance GenericLayout (P.ParagraphLayout d) where
     empty = P.emptyParagraphLayout
     rect = P.paragraphRect
     topDistance pl = topFragmentOrigin $ P.paragraphFragments pl
-    lineNumbers pl = uniqueFragmentLines $ P.paragraphFragments pl
     limitFragments n = P.filterFragments (fragmentIsOnLine n)
     shiftFragments dy = P.mapFragments (shiftFragment dy)
     appendFragments = P.appendFragments
@@ -51,13 +47,12 @@ instance GenericLayout (R.ParagraphLayout d) where
     empty = R.emptyParagraphLayout
     rect = R.paragraphRect
     topDistance pl = topFragmentOrigin $ R.paragraphFragments pl
-    lineNumbers pl = uniqueFragmentLines $ R.paragraphFragments pl
     limitFragments n = R.filterFragments (fragmentIsOnLine n)
     shiftFragments dy = R.mapFragments (shiftFragment dy)
     appendFragments = R.appendFragments
 
 -- | Split the given paragraph layout into single-line layouts.
-cutLines :: GenericLayout pl => pl -> [pl]
+cutLines :: (GenericLayout pl, LineNumbers pl) => pl -> [pl]
 cutLines pl = map (\ n -> cutLine n pl) (lineNumbers pl)
 
 -- | Reduce the given paragraph layout to fragments with the given line number.
@@ -71,13 +66,6 @@ trimTop pl = shiftFragments (-topDistance pl) pl
 topFragmentOrigin :: [Fragment d] -> Int32
 topFragmentOrigin frags = maximum $ map (y_origin . fragmentRect) frags
 
-uniqueFragmentLines :: [Fragment d] -> [Int]
-uniqueFragmentLines frags = dedupe $ map fragmentLine frags
-
--- | Remove duplicates from a sorted list.
-dedupe :: Eq a => [a] -> [a]
-dedupe xs = map NonEmpty.head $ NonEmpty.group xs
-
 -- | Put the given paragraph layouts together as a vertically contiguous
 -- sequence.
 mergeLines :: GenericLayout pl => [pl] -> pl
diff --git a/src/Data/Text/ParagraphLayout/Internal/Plain/ParagraphLayout.hs b/src/Data/Text/ParagraphLayout/Internal/Plain/ParagraphLayout.hs
index 5f18917..ddad8ac 100644
--- a/src/Data/Text/ParagraphLayout/Internal/Plain/ParagraphLayout.hs
+++ b/src/Data/Text/ParagraphLayout/Internal/Plain/ParagraphLayout.hs
@@ -13,6 +13,7 @@ where
 import Data.Int (Int32)
 
 import Data.Text.ParagraphLayout.Internal.Fragment
+import Data.Text.ParagraphLayout.Internal.LineNumbers
 import Data.Text.ParagraphLayout.Internal.LinePagination
 import Data.Text.ParagraphLayout.Internal.ParagraphExtents
 import Data.Text.ParagraphLayout.Internal.Rect
@@ -26,6 +27,9 @@ data ParagraphLayout d = ParagraphLayout
     }
     deriving (Eq, Read, Show)
 
+instance LineNumbers (ParagraphLayout d) where
+    lineNumbersWithDuplication pl = map fragmentLine $ paragraphFragments pl
+
 instance Line (ParagraphLayout d) where
     lineHeight pl = height $ paragraphRect pl
 
diff --git a/src/Data/Text/ParagraphLayout/Internal/Rich/ParagraphLayout.hs b/src/Data/Text/ParagraphLayout/Internal/Rich/ParagraphLayout.hs
index 50e4c99..719a6de 100644
--- a/src/Data/Text/ParagraphLayout/Internal/Rich/ParagraphLayout.hs
+++ b/src/Data/Text/ParagraphLayout/Internal/Rich/ParagraphLayout.hs
@@ -14,6 +14,7 @@ where
 import Data.Int (Int32)
 
 import Data.Text.ParagraphLayout.Internal.Fragment
+import Data.Text.ParagraphLayout.Internal.LineNumbers
 import Data.Text.ParagraphLayout.Internal.LinePagination
 import Data.Text.ParagraphLayout.Internal.ParagraphExtents
 import Data.Text.ParagraphLayout.Internal.Rect
@@ -29,6 +30,9 @@ data ParagraphLayout d = ParagraphLayout
     }
     deriving (Eq, Read, Show)
 
+instance LineNumbers (ParagraphLayout d) where
+    lineNumbersWithDuplication pl = map fragmentLine $ paragraphFragments pl
+
 instance Line (ParagraphLayout d) where
     lineHeight pl = height $ paragraphRect pl
 
-- 
2.30.2