From 54f93cd9cafeeb539745cee24ea86f2cba32ce98 Mon Sep 17 00:00:00 2001
From: Daniel Bergey <bergey@teallabs.org>
Date: Tue, 10 Nov 2015 21:13:04 -0500
Subject: [PATCH 1/8] add haskell-mode-toggle-scc-at-point

---
 haskell-mode.el | 39 +++++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/haskell-mode.el b/haskell-mode.el
index 6ce955509..6a75540f8 100644
--- a/haskell-mode.el
+++ b/haskell-mode.el
@@ -891,9 +891,9 @@ LOC = (list FILE LINE COL)"
 
 ;; From Bryan O'Sullivan's blog:
 ;; http://www.serpentine.com/blog/2007/10/09/using-emacs-to-insert-scc-annotations-in-haskell-code/
-(defun haskell-mode-insert-scc-at-point ()
-  "Insert an SCC annotation at point."
-  (interactive)
+(defun haskell-mode-try-insert-scc-at-point ()
+  "Try to insert an SCC annotation at point.  Return true if
+successful, nil otherwise."
   (if (or (looking-at "\\b\\|[ \t]\\|$") (and (not (bolp))
                                               (save-excursion
                                                 (forward-char -1)
@@ -906,13 +906,18 @@ LOC = (list FILE LINE COL)"
         (insert "{-# SCC \"\" #-}")
         (unless space-at-point
           (insert " "))
-        (forward-char (if space-at-point -5 -6)))
-    (error "Not over an area of whitespace")))
+        (forward-char (if space-at-point -5 -6))
+        t )))
 
-;; Also Bryan O'Sullivan's.
-(defun haskell-mode-kill-scc-at-point ()
-  "Kill the SCC annotation at point."
+(defun haskell-mode-insert-scc-at-point ()
+  "Insert an SCC annotation at point."
   (interactive)
+  (if (not (haskell-mode-try-insert-scc-at-point))
+      (error "Not over an area of whitespace")))
+
+(defun haskell-mode-try-kill-scc-at-point ()
+  "Try to kill an SCC annotation at point.  Return true if
+successful, nil otherwise."
   (save-excursion
     (let ((old-point (point))
           (scc "\\({-#[ \t]*SCC \"[^\"]*\"[ \t]*#-}\\)[ \t]*"))
@@ -921,8 +926,22 @@ LOC = (list FILE LINE COL)"
       (if (and (looking-at scc)
                (<= (match-beginning 1) old-point)
                (> (match-end 1) old-point))
-          (kill-region (match-beginning 0) (match-end 0))
-        (error "No SCC at point")))))
+          (progn (kill-region (match-beginning 0) (match-end 0))
+                 t)))))
+
+;; Also Bryan O'Sullivan's.
+(defun haskell-mode-kill-scc-at-point ()
+  "Kill the SCC annotation at point."
+  (interactive)
+  (if (not (haskell-mode-try-kill-scc-at-point))
+      (error "No SCC at point")))
+
+(defun haskell-mode-toggle-scc-at-point ()
+  "If point is in an SCC annotation, kill the annotation.  Otherwise, try to insert a new annotation."
+  (interactive)
+  (if (not (haskell-mode-try-kill-scc-at-point))
+      (if (not (haskell-mode-try-insert-scc-at-point))
+          (error "Could not insert or remove SCC"))))
 
 (defun haskell-guess-module-name ()
   "Guess the current module name of the buffer."

From ea332606d9a5c514fdf9371532f4b3d589f746d2 Mon Sep 17 00:00:00 2001
From: Daniel Bergey <bergey@teallabs.org>
Date: Tue, 10 Nov 2015 21:51:27 -0500
Subject: [PATCH 2/8] bind haskell-mode-toggle-scc-at-point to C-c C-s

---
 haskell-mode.el | 1 +
 1 file changed, 1 insertion(+)

diff --git a/haskell-mode.el b/haskell-mode.el
index 6a75540f8..1d7e385c0 100644
--- a/haskell-mode.el
+++ b/haskell-mode.el
@@ -202,6 +202,7 @@ be set to the preferred literate style."
     (define-key map (kbd "C-c C-v") 'haskell-mode-enable-process-minor-mode)
     (define-key map (kbd "C-c C-t") 'haskell-mode-enable-process-minor-mode)
     (define-key map (kbd "C-c C-i") 'haskell-mode-enable-process-minor-mode)
+    (define-key map (kbd "C-c C-s") 'haskell-mode-toggle-scc-at-point)
     map)
   "Keymap used in Haskell mode.")
 

From 0deae63b2f6ead9e2298aa47be6096384e2cc475 Mon Sep 17 00:00:00 2001
From: Daniel Bergey <bergey@teallabs.org>
Date: Tue, 10 Nov 2015 21:55:13 -0500
Subject: [PATCH 3/8] Document `toggle-scc-at-point` in manual

---
 doc/haskell-mode.texi | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/doc/haskell-mode.texi b/doc/haskell-mode.texi
index 7d932e767..99108071f 100644
--- a/doc/haskell-mode.texi
+++ b/doc/haskell-mode.texi
@@ -278,6 +278,15 @@ and available packages.
 @image{anim/company-mode-import-statement}
 @end ifhtml
 
+@section Profiling and Debugging support
+
+When profiling code with GHC, it is often useful to add
+@uref{https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/profiling.html#cost-centres,
+cost centres} by hand.  These allow finer-grained information about
+program behavior.  @code{haskell-mode} provides the function
+@code{haskell-mode-toggle-scc-at-point} to make this more convenient.
+It will remove an SCC annotation at point if one is present, or add
+one if point is over whitespace.  By default it is bound to @kbd{C-c C-s}.
 
 @node Unicode support
 @chapter Unicode support

From b82c5dcdb9631ff81ea9b8d267d7d26a0c6e0bad Mon Sep 17 00:00:00 2001
From: Daniel Bergey <bergey@teallabs.org>
Date: Tue, 10 Nov 2015 22:25:00 -0500
Subject: [PATCH 4/8] add unit tests for toggle-scc-at-point

---
 tests/haskell-mode-tests.el | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/tests/haskell-mode-tests.el b/tests/haskell-mode-tests.el
index 078c246e7..7a0a88c15 100644
--- a/tests/haskell-mode-tests.el
+++ b/tests/haskell-mode-tests.el
@@ -170,7 +170,7 @@
   (should (with-temp-buffer
             (haskell-mode)
             (insert "Äöèąċōïá")
-            (string= "Äöèąċōïá" (haskell-ident-at-point)))))            
+            (string= "Äöèąċōïá" (haskell-ident-at-point)))))
 
 (ert-deftest unicode-pos ()
   (should (with-temp-buffer
@@ -385,4 +385,31 @@ Also should respect 10 column fill."
 	      '("-- @| a b c d"
                 "-- e")))
 
+(ert-deftest insert-scc-feasible ()
+  "insert an SCC where it's possible to do so"
+  (should (with-temp-buffer
+            (insert "hello world")
+            (goto-char 6)
+            (haskell-mode-toggle-scc-at-point)
+            (string= "hello {-# SCC \"\" #-} world"
+                     (buffer-substring 1 (point-max))))))
+
+(ert-deftest insert-scc-infeasible ()
+  "insert an SCC where it's not possible to do so"
+  (should-error (with-temp-buffer
+            (insert "hello world")
+            (goto-char 3)
+            (haskell-mode-toggle-scc-at-point)
+            (string= "hello world"
+                     (buffer-substring 1 (point-max))))))
+
+(ert-deftest remove-scc ()
+  "insert an SCC where it's possible to do so"
+  (should (with-temp-buffer
+            (insert "hello {-# SCC \"\" #-} world")
+            (goto-char 10)
+            (haskell-mode-toggle-scc-at-point)
+            (string= "hello world"
+                     (buffer-substring 1 (point-max))))))
+
 (provide 'haskell-mode-tests)

From f1b104b6200f05daec06f452c9ac128797b06777 Mon Sep 17 00:00:00 2001
From: Daniel Bergey <bergey@teallabs.org>
Date: Tue, 10 Nov 2015 23:06:52 -0500
Subject: [PATCH 5/8] modify tests to expose bug in SCC code

If point is on the second character of a word,
haskell-mode-try-scc-at-point will break the word, inserting an SCC
annotation between the first and second characters.
---
 tests/haskell-mode-tests.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/haskell-mode-tests.el b/tests/haskell-mode-tests.el
index 7a0a88c15..6dba27b2b 100644
--- a/tests/haskell-mode-tests.el
+++ b/tests/haskell-mode-tests.el
@@ -398,7 +398,7 @@ Also should respect 10 column fill."
   "insert an SCC where it's not possible to do so"
   (should-error (with-temp-buffer
             (insert "hello world")
-            (goto-char 3)
+            (goto-char 2)
             (haskell-mode-toggle-scc-at-point)
             (string= "hello world"
                      (buffer-substring 1 (point-max))))))

From 5c96cd13d6ad728dfcd33265ecd114552ed850ad Mon Sep 17 00:00:00 2001
From: Daniel Bergey <bergey@teallabs.org>
Date: Tue, 10 Nov 2015 23:08:35 -0500
Subject: [PATCH 6/8] fix second-char bug in SCC code

Don't insert SCC if the character before point is the beginning of a
word.  Do insert SCC if the character at point is not the beginning of a
word, but the character before point is whitespace.  This occurs when
the character at point is a non-letter, such as = or {.
---
 haskell-mode.el | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/haskell-mode.el b/haskell-mode.el
index 1d7e385c0..5119b6883 100644
--- a/haskell-mode.el
+++ b/haskell-mode.el
@@ -895,10 +895,12 @@ LOC = (list FILE LINE COL)"
 (defun haskell-mode-try-insert-scc-at-point ()
   "Try to insert an SCC annotation at point.  Return true if
 successful, nil otherwise."
-  (if (or (looking-at "\\b\\|[ \t]\\|$") (and (not (bolp))
-                                              (save-excursion
-                                                (forward-char -1)
-                                                (looking-at "\\b\\|[ \t]"))))
+  (if (or (looking-at "\\b\\|[ \t]\\|$")
+          ;; Allow SCC if point is on a non-letter with whitespace to the left
+          (and (not (bolp))
+               (save-excursion
+                 (forward-char -1)
+                 (looking-at "[ \t]"))))
       (let ((space-at-point (looking-at "[ \t]")))
         (unless (and (not (bolp)) (save-excursion
                                     (forward-char -1)

From 5ce8ad47774ecc534616b6e889131a72e4655f6c Mon Sep 17 00:00:00 2001
From: Daniel Bergey <bergey@teallabs.org>
Date: Wed, 11 Nov 2015 07:35:08 -0500
Subject: [PATCH 7/8] mark old SCC functions as obsolete

---
 haskell-mode.el | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/haskell-mode.el b/haskell-mode.el
index 5119b6883..51c961fd6 100644
--- a/haskell-mode.el
+++ b/haskell-mode.el
@@ -918,6 +918,10 @@ successful, nil otherwise."
   (if (not (haskell-mode-try-insert-scc-at-point))
       (error "Not over an area of whitespace")))
 
+(make-obsolete
+ 'haskell-mode-insert-scc-at-point
+ 'haskell-mode-toggle-scc-at-point)
+
 (defun haskell-mode-try-kill-scc-at-point ()
   "Try to kill an SCC annotation at point.  Return true if
 successful, nil otherwise."
@@ -939,6 +943,10 @@ successful, nil otherwise."
   (if (not (haskell-mode-try-kill-scc-at-point))
       (error "No SCC at point")))
 
+(make-obsolete
+ 'haskell-mode-kill-scc-at-point
+ 'haskell-mode-toggle-scc-at-point)
+
 (defun haskell-mode-toggle-scc-at-point ()
   "If point is in an SCC annotation, kill the annotation.  Otherwise, try to insert a new annotation."
   (interactive)

From d8d61af1dc230a530cf401d7c6717974940bf973 Mon Sep 17 00:00:00 2001
From: Daniel Bergey <bergey@teallabs.org>
Date: Wed, 11 Nov 2015 08:08:00 -0500
Subject: [PATCH 8/8] In make-obsolete, give date of obsolescence

---
 haskell-mode.el | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/haskell-mode.el b/haskell-mode.el
index 51c961fd6..f22cea8e3 100644
--- a/haskell-mode.el
+++ b/haskell-mode.el
@@ -920,7 +920,8 @@ successful, nil otherwise."
 
 (make-obsolete
  'haskell-mode-insert-scc-at-point
- 'haskell-mode-toggle-scc-at-point)
+ 'haskell-mode-toggle-scc-at-point
+ "2015-11-11")
 
 (defun haskell-mode-try-kill-scc-at-point ()
   "Try to kill an SCC annotation at point.  Return true if
@@ -945,7 +946,8 @@ successful, nil otherwise."
 
 (make-obsolete
  'haskell-mode-kill-scc-at-point
- 'haskell-mode-toggle-scc-at-point)
+ 'haskell-mode-toggle-scc-at-point
+ "2015-11-11")
 
 (defun haskell-mode-toggle-scc-at-point ()
   "If point is in an SCC annotation, kill the annotation.  Otherwise, try to insert a new annotation."