From ec4e3a8f0d95091f8f43c046e6e355060e84b274 Mon Sep 17 00:00:00 2001
From: Mateusz Kowalczyk <fuuzetsu@fuuzetsu.co.uk>
Date: Fri, 24 Oct 2014 17:55:58 +0100
Subject: [PATCH] Fix eolPoint' manouvers

Fixes #667 and probably #662 (needs vimtests) and maybe even more.
---
 CHANGELOG                                  |  1 +
 yi/src/library/Yi/Buffer/Implementation.hs | 29 +++++++++++++---------
 yi/src/library/Yi/Buffer/TextUnit.hs       |  6 ++---
 3 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index b3289514d..ce14e4012 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -3,6 +3,7 @@
 
  * Try to guess and preserve the file encoding (#638)
  * Restore cursor position better after deleteTrailingSpacesB (#666)
+ * Fix eolPoint' when on last, empty line (#667)
 
 0.10.0
 ------
diff --git a/yi/src/library/Yi/Buffer/Implementation.hs b/yi/src/library/Yi/Buffer/Implementation.hs
index 4704a241d..08199ea50 100644
--- a/yi/src/library/Yi/Buffer/Implementation.hs
+++ b/yi/src/library/Yi/Buffer/Implementation.hs
@@ -39,7 +39,6 @@ module Yi.Buffer.Implementation
   , newBI
   , solPoint
   , solPoint'
-  , eolPoint
   , eolPoint'
   , charsFromSolBI
   , regexRegionBI
@@ -347,23 +346,29 @@ solPoint line fb = Point $ R.length $ fst $ R.splitAtLine (line - 1) (mem fb)
 -- | Point that's at EOL. Notably, this puts you right before the
 -- newline character if one exists, and right at the end of the text
 -- if one does not.
-eolPoint :: Int -- ^ Line for which to grab EOL for
-         -> BufferImpl syntax -> Point
-eolPoint l = Point . checkEol . fst . R.splitAtLine l . mem
+eolPoint :: Point
+            -- ^ Point from which we take the line to find the EOL of
+         -> BufferImpl syntax
+         -> Point
+eolPoint' p@(Point ofs) fb = Point . checkEol . fst . R.splitAtLine ln $ mem fb
   where
-    -- In case we're somewhere without trailing newline, we need to stay where we are
-    checkEol t = let l' = R.length t in case R.last t of
-      Just '\n' -> l' - 1
-      _ -> l'
+    ln = lineAt p fb
+    -- In case we're somewhere without trailing newline, we need to
+    -- stay where we are
+    checkEol t =
+      let l' = R.length t
+      in case R.last t of
+          -- We're looking at EOL and we weren't asking for EOL past
+          -- this point, so back up one for good visual effect
+          Just '\n' | l' > ofs -> l' - 1
+          -- We asked for EOL past the last newline so just go to the
+          -- very end of content
+          _ -> l'
 
 -- | Get begining of the line relatively to @point@.
 solPoint' :: Point -> BufferImpl syntax -> Point
 solPoint' point fb = solPoint (lineAt point fb) fb
 
--- | Get end of the line relative to the point.
-eolPoint' :: Point -> BufferImpl s -> Point
-eolPoint' p fb = eolPoint (lineAt p fb) fb
-
 charsFromSolBI :: Point -> BufferImpl syntax -> YiString
 charsFromSolBI pnt fb = nelemsBI (fromIntegral $ pnt - sol) sol fb
     where sol = solPoint' pnt fb
diff --git a/yi/src/library/Yi/Buffer/TextUnit.hs b/yi/src/library/Yi/Buffer/TextUnit.hs
index f500e5c4c..9672ab23e 100644
--- a/yi/src/library/Yi/Buffer/TextUnit.hs
+++ b/yi/src/library/Yi/Buffer/TextUnit.hs
@@ -314,9 +314,9 @@ genMoveB Document _                     Forward = moveTo =<< sizeB
 genMoveB Document _ Backward = moveTo 0 -- impossible to go outside beginning of doc.
 genMoveB Character _ Forward  = rightB
 genMoveB Character _ Backward = leftB
-genMoveB VLine     _ Forward  =
-  do ofs <- lineMoveRel 1
-     when (ofs < 1) (maybeMoveB Line Forward)
+genMoveB VLine     _ Forward  = do
+  ofs <- lineMoveRel 1
+  when (ofs < 1) (maybeMoveB Line Forward)
 genMoveB VLine _ Backward = lineUp
 genMoveB unit (boundDir, boundSide) moveDir =
   doUntilB_ (genAtBoundaryB unit boundDir boundSide) (moveB Character moveDir)