Added import jumping/navigation.

Makefile

@@ -16,6 +16,7 @@ ELFILES = \
 	haskell-sort-imports.el \
 	haskell-align-imports.el \
 	haskell-move-nested.el \
+	haskell-navigate-imports.el \
 	ghc-core.el \
 	inf-haskell.el
 

haskell-mode.el

@@ -247,6 +247,7 @@ be set to the preferred literate style."
     (define-key map (kbd "C-c C-d") 'inferior-haskell-find-haddock)
 
     (define-key map (kbd "C-c C-.") 'haskell-mode-format-imports)
+    (define-key map (kbd "C-c i") 'haskell-navigate-imports)
 
     (define-key map [?\C-c ?\C-v] 'haskell-check)
 

haskell-navigate-imports.el

@@ -0,0 +1,110 @@
+;; haskell-navigate-imports.el — A function for cycling through Haskell import lists.
+;; Copyright (C) 2010 Chris Done <chrisdone@gmail.com>
+
+;; The cycling step will stop once at the last import list so
+;; that it is easy to add a new import list.
+
+;; This module works completely independently of any libraries
+;; (including haskell-mode).
+
+;; Exports three interactive functions:
+;; 1. haskell-navigate-imports
+;; 2. haskell-navigate-imports-go
+;; 3. haskell-navigate-imports-return
+
+;; Example usage:
+
+;; (require 'haskell-navigate-imports)
+;; (define-key haskell-mode-map [f8] 'haskell-navigate-imports)
+
+;; This program is free software: you can redistribute it and/or
+;; modify it under the terms of the GNU General Public License as
+;; published by the Free Software Foundation, either version 3 of
+;; the License, or (at your option) any later version.
+
+;; This program is distributed in the hope that it will be
+;; useful, but WITHOUT ANY WARRANTY; without even the implied
+;; warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+;; PURPOSE.  See the GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public
+;; License along with this program.  If not, see
+;; <http://www.gnu.org/licenses/>.
+
+(defvar haskell-navigate-imports-start-point nil)
+
+;;;###autoload
+(defun haskell-navigate-imports (&optional return)
+  "Cycle the Haskell import lines or return to point (with prefix arg)."
+  (interactive "P")
+  (if return
+      (haskell-navigate-imports-return)
+    (haskell-navigate-imports-go)))
+
+;;;###autoload
+(defun haskell-navigate-imports-go ()
+  "Go to the first line of a list of consequtive import lines. Cycles."
+  (interactive)
+  (unless (or (haskell-navigate-imports-line)
+              (equal (line-beginning-position) (point-min))
+              (save-excursion (previous-line)
+                              (haskell-navigate-imports-line)))
+    (setq haskell-navigate-imports-start-point (point)))
+  (haskell-navigate-imports-go-internal))
+
+;;;###autoload
+(defun haskell-navigate-imports-return ()
+  "Return to the non-import point we were at before going to the module list.
+   If we were originally at an import list, we can just cycle through easily."
+  (interactive)
+  (when haskell-navigate-imports-start-point
+    (goto-char haskell-navigate-imports-start-point)))
+
+(defun haskell-navigate-imports-go-internal ()
+  "Go to the first line of a list of consequtive import lines. Cycle."
+  (if (haskell-navigate-imports-line)
+      (progn (haskell-navigate-imports-goto-end)
+             (when (haskell-navigate-imports-find-forward-line)
+               (haskell-navigate-imports-go-internal)))
+    (let ((point (haskell-navigate-imports-find-forward-line)))
+      (if point
+          (goto-char point)
+        (progn (goto-char (point-min))
+               (when (haskell-navigate-imports-find-forward-line)
+                 (haskell-navigate-imports-go-internal)))))))
+
+(defun haskell-navigate-imports-goto-end ()
+  "Skip a bunch of consequtive import lines."
+  (while (not (or (equal (point)
+                         (point-max))
+                  (not (haskell-navigate-imports-line))))
+    (forward-line)))
+
+(defun haskell-navigate-imports-find-forward-line ()
+  "Return a point with at an import line, or nothing."
+  (save-excursion
+    (while (not (or (equal (point) (point-max))
+                    (haskell-navigate-imports-after-imports-p) ;; This one just speeds it up.
+                    (haskell-navigate-imports-line)))
+      (forward-line))
+    (let ((point (point)))
+      (if (haskell-navigate-imports-line)
+          (point)
+        nil))))
+
+(defun haskell-navigate-imports-line ()
+  "Try to match the current line as a regexp."
+  (let ((line (buffer-substring-no-properties (line-beginning-position)
+                                              (line-end-position))))
+    (if (string-match "^import " line)
+        line
+      nil)))
+
+(defun haskell-navigate-imports-after-imports-p ()
+  "Are we after the imports list? Just for a speed boost."
+  (save-excursion
+    (goto-char (line-beginning-position))
+    (not (not (search-forward-regexp "\\( = \\|\\<instance\\>\\| :: \\)"
+                                     (line-end-position) t 1)))))
+
+(provide 'haskell-navigate-imports)