From 7e9b61f4c76c2d41e26329ceed0ff7d225a7882c Mon Sep 17 00:00:00 2001
From: Gracjan Polak <gracjan@scrive.com>
Date: Tue, 20 Jan 2015 20:44:55 +0100
Subject: [PATCH 1/2] Keep final space after fill-paragraph.

Before this commit {- a -} got paragraph filled as {- a-} (notice
missing space). Now this space is kept in place properly.
---
 haskell-mode.el | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/haskell-mode.el b/haskell-mode.el
index 1b01cc1b3..4ddc56092 100644
--- a/haskell-mode.el
+++ b/haskell-mode.el
@@ -748,11 +748,11 @@ see documentation for that variable for more details."
                   (forward-sexp)
                   ;; Find end of any comment even if forward-sexp
                   ;; fails to find the right braces.
-                  (backward-char 2)
-                  (re-search-forward "-}" nil t)
-                  (point)))
+                  (backward-char 3)
+                  (re-search-forward "[ \t]?-}" nil t)
+                  (match-beginning 0)))
                (fill-start (+ 2 comment-start-point))
-               (fill-end (- comment-end-point 2))
+               (fill-end comment-end-point)
                (fill-paragraph-handle-comment nil))
           (save-restriction
             (narrow-to-region fill-start fill-end)

From d7a973c33b8b12cc94fb9ed072e8cf582cdae6d3 Mon Sep 17 00:00:00 2001
From: Gracjan Polak <gracjan@scrive.com>
Date: Tue, 20 Jan 2015 20:46:35 +0100
Subject: [PATCH 2/2] Tests for fill-comment.

ERT tests for working and not working cases of paragraph filling in
Haskell comments.
---
 tests/haskell-mode-tests.el | 152 ++++++++++++++++++++++++++++++++++++
 1 file changed, 152 insertions(+)

diff --git a/tests/haskell-mode-tests.el b/tests/haskell-mode-tests.el
index 7e9d50ce4..c3668d326 100644
--- a/tests/haskell-mode-tests.el
+++ b/tests/haskell-mode-tests.el
@@ -129,4 +129,156 @@
             (insert "Äöèąċōïá")
             (string= "Äöèąċōïá" (haskell-ident-at-point)))))
 
+(defun check-fill (expected initial)
+  "Check using ERT if `fill-paragraph' over `initial' gives
+`expected' result. Cursor fill be positioned at '@' character or at
+the beginning of the buffer.
+
+`fill-column' will be set to 10 so that it is easy to spot issues."
+  (should (equal expected
+		 (with-temp-buffer
+		   (haskell-mode)
+		   (setq fill-column 10)
+		   (dolist (line initial)
+		     (insert line)
+		     (insert "\n"))
+		   (goto-char (point-min))
+		   (skip-chars-forward "^@")
+		   (if (eobp)
+		       (goto-char (point-min))
+		     (delete-char 1))
+		   (fill-paragraph nil)
+		   (split-string (buffer-substring-no-properties (point-min) (1- (point-max))) "\n")))))
+
+(ert-deftest fill-comment-1 ()
+  (check-fill '("{- a -}")
+	      '("{- @a -}")))
+
+(ert-deftest fill-comment-2 ()
+  (check-fill '("{- a b c d e"
+		"f g h i j"
+		"k -}")
+	      '("{- @a b c d e f g h i j k -}")))
+
+(ert-deftest fill-comment-3 ()
+  (check-fill '("{-"
+		"a"
+		"-}")
+	      '("{-"
+		"@a"
+		"-}")))
+
+(ert-deftest fill-comment-4 ()
+  (check-fill '("{-"
+		"a b c d e"
+		"f g h i-}")
+	      '("{-"
+		"@a"
+		"b"
+		"c"
+		"d e f g h i-}")))
+
+(ert-deftest fill-comment-5 ()
+  (check-fill '("    {-"
+		" a b c d e"
+		"f g h i"
+		"    -}")
+	      '("    {-" " @a b c d e f g h i" "    -}")))
+
+(ert-deftest fill-comment-6 ()
+  (check-fill '("  -- a b c"
+		"  -- d e f"
+		"  -- g h i"
+		"  -- j k l"
+		"  -- m n o"
+		"  -- p q r"
+		"  -- s t u"
+		"  -- v")
+	      '("  -- @a b c d e f g h i j k l m n o p q r s t u v")))
+
+(ert-deftest fill-comment-7 ()
+  (check-fill '("  --  a b"
+		"  --  c d"
+		"  --  e f"
+		"  --  g h"
+		"  --  i j")
+	      '("  --  @a b c d e f g h i j ")))
+
+(ert-deftest fill-comment-8 ()
+  "Note: first letter of second line should be in the same column
+as first letter in the first line.
+
+Also should respect 10 column fill."
+  :expected-result :failed
+  (check-fill '("  {-  a b"
+		"      c d"
+		"      e f"
+		"      g h"
+		"      i j"
+		"   -}")
+	      '("  {-  @a b c d e f g h i j"
+		"  -}")))
+
+(ert-deftest fill-comment-9 ()
+  "Note: first letter in the second line position should be kept
+as defined, just the content should move properly.
+
+Also should respect 10 column fill."
+  :expected-result :failed
+  (check-fill '("  {-  a b"
+		"     c d e"
+		"     f g h"
+		"     i j"
+		"   -}")
+	      '("  {-  @a"
+		"     b c d e f g h i j"
+		"  -}")))
+
+(ert-deftest fill-comment-10 ()
+  "Note: first letter in the second line position should be kept
+as defined, just the content should move properly. Following
+lines should take position from second line.
+
+Also should respect 10 column fill."
+  :expected-result :failed
+  (check-fill '("  {-  a b"
+		"     c d e"
+		"     f g h"
+		"     i j"
+		"   -}")
+	      '("  {-  @a"
+		"     b c d e"
+		"  f g h"
+		"                    i j"
+		"  -}")))
+
+(ert-deftest fill-comment-11 ()
+  "Note: first letter in the second line position should be kept
+as defined, just the content should move properly.
+
+Also should respect 10 column fill."
+  :expected-result :failed
+  (check-fill '("  --  a b"
+		"  -- c d e"
+		"  -- f g h"
+		"  -- i j")
+	      '("  --  @a"
+		"  -- b c d e f g h i j")))
+
+(ert-deftest fill-comment-12 ()
+  "Note: first letter in the second line position should be kept
+as defined, just the content should move properly. Following
+lines should take position from second line.
+
+Also should respect 10 column fill."
+  :expected-result :failed
+  (check-fill '("  --  a b"
+		"  -- c d e"
+		"  -- f g h"
+		"  -- i j")
+	      '("  --  @a"
+		"  -- b c d e"
+		"--f g h"
+		"        --            i j")))
+
 (provide 'haskell-mode-tests)