Make haskell indentation the default indentation mode

haskell-indent.el

@@ -1520,6 +1520,10 @@ One indentation cycle is used."
 ;;;###autoload
 (defun turn-on-haskell-indent ()
   "Turn on ``intelligent'' Haskell indentation mode."
+  (when (and (bound-and-true-p haskell-indentation-mode)
+             (fboundp 'haskell-indentation-mode))
+    (haskell-indentation-mode 0))
+
   (set (make-local-variable 'indent-line-function) 'haskell-indent-cycle)
   (set (make-local-variable 'indent-region-function) 'haskell-indent-region)
   (setq haskell-indent-mode t)

haskell-indentation.el

@@ -151,6 +151,12 @@ clashing with other modes."
   (kill-local-variable 'indent-region-function)
 
   (when haskell-indentation-mode
+    (when (and (bound-and-true-p haskell-indent-mode)
+               (fboundp 'turn-off-haskell-indent))
+      (turn-off-haskell-indent))
+    (when (and (bound-and-true-p haskell-simple-indent-mode)
+               (fboundp 'haskell-simple-indent-mode))
+      (haskell-simple-indent-mode 0))
     (set (make-local-variable 'indent-line-function)
          'haskell-indentation-indent-line)
     (set (make-local-variable 'indent-region-function)

haskell-mode.el

@@ -139,6 +139,7 @@
 (require 'haskell-lexeme)
 (require 'haskell-sort-imports)
 (require 'haskell-string)
+(require 'haskell-indentation)
 
 ;; All functions/variables start with `(literate-)haskell-'.
 
@@ -656,7 +657,7 @@ Minor modes that work well with `haskell-mode':
   (set (make-local-variable 'comment-end-skip) "[ \t]*\\(-}\\|\\s>\\)")
   (set (make-local-variable 'forward-sexp-function) #'haskell-forward-sexp)
   (set (make-local-variable 'parse-sexp-ignore-comments) nil)
-  (set (make-local-variable 'indent-line-function) 'haskell-mode-suggest-indent-choice)
+
   ;; Set things up for eldoc-mode.
   (set (make-local-variable 'eldoc-documentation-function)
        'haskell-doc-current-info)
@@ -693,7 +694,7 @@ Minor modes that work well with `haskell-mode':
   (setq haskell-literate nil)
   (add-hook 'before-save-hook 'haskell-mode-before-save-handler nil t)
   (add-hook 'after-save-hook 'haskell-mode-after-save-handler nil t)
-  )
+  (haskell-indentation-mode))
 
 (defun haskell-fill-paragraph (justify)
   (save-excursion
@@ -979,14 +980,6 @@ To be added to `flymake-init-create-temp-buffer-copy'."
 
 (add-to-list 'flymake-allowed-file-name-masks '("\\.l?hs\\'" haskell-flymake-init))
 
-(defun haskell-mode-suggest-indent-choice ()
-  "Ran when the user tries to indent in the buffer but no indentation mode has been selected.
-Explains what has happened and suggests reading docs for `haskell-mode-hook'."
-  (interactive)
-  (error "You tried to do an indentation command, but an indentation mode has not been enabled yet.
-
-Run M-x describe-variable haskell-mode-hook for a list of such modes."))
-
 (defun haskell-mode-format-imports ()
   "Format the imports by aligning and sorting them."
   (interactive)

haskell-simple-indent.el

@@ -244,6 +244,9 @@ Runs `haskell-simple-indent-hook' on activation."
   (kill-local-variable 'comment-indent-function)
   (kill-local-variable 'indent-line-function)
   (when haskell-simple-indent-mode
+    (when (and (bound-and-true-p haskell-indentation-mode)
+               (fboundp 'haskell-indentation-mode))
+      (haskell-indentation-mode 0))
     (set (make-local-variable 'comment-indent-function) #'haskell-simple-indent-comment-indent-function)
     (set (make-local-variable 'indent-line-function) 'haskell-simple-indent)
     (run-hooks 'haskell-simple-indent-hook)))

tests/haskell-indentation-tests.el

@@ -27,6 +27,8 @@
 (require 'haskell-mode)
 (require 'haskell-font-lock)
 (require 'haskell-indentation)
+(require 'haskell-indent)
+(require 'haskell-simple-indent)
 
 ;;; Code:
 
@@ -113,6 +115,32 @@ macro quotes them for you."
                       (list 'quote x))
                     test-cases))))))
 
+(ert-deftest haskell-indentation-turns-off-haskell-indent ()
+  (with-temp-buffer
+    (haskell-mode)
+    (haskell-indent-mode)
+    (should haskell-indent-mode)
+    (haskell-indentation-mode)
+    (should haskell-indentation-mode)
+    (should-not haskell-indent-mode)
+
+    (haskell-indent-mode)
+    (should-not haskell-indentation-mode)
+    (should haskell-indent-mode)))
+
+(ert-deftest haskell-indentation-turns-off-haskell-simple-indent ()
+  (with-temp-buffer
+    (haskell-mode)
+    (haskell-simple-indent-mode)
+    (should haskell-simple-indent-mode)
+    (haskell-indentation-mode)
+    (should haskell-indentation-mode)
+    (should-not haskell-simple-indent-mode)
+
+    (haskell-simple-indent-mode)
+    (should-not haskell-indentation-mode)
+    (should haskell-simple-indent-mode)))
+
 (hindent-test "1 Check if '{' on its own line gets properly indented""
 function = Record
        { field = 123 }"