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;;; haskell-navigate-imports.el --- A function for cycling through Haskell import lists -*- lexical-binding: t -*-
;; Copyright (C) 2010 Chris Done
;; Author: Chris Done <>
;; This file is not part of GNU Emacs.
;; 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
;; 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
;; <>.
;;; Commentary:
;; 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 (kbd "<f8>") 'haskell-navigate-imports)
;;; Code:
(defvar haskell-navigate-imports-start-point nil)
(defun haskell-navigate-imports (&optional return)
"Cycle the Haskell import lines or return to point (with prefix arg)."
(interactive "P")
(if return
(defun haskell-navigate-imports-go ()
"Go to the first line of a list of consecutive import lines. Cycles."
(unless (or (haskell-navigate-imports-line)
(equal (line-beginning-position) (point-min))
(save-excursion (forward-line -1)
(setq haskell-navigate-imports-start-point (point)))
(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."
(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 consecutive import lines. Cycle."
(if (haskell-navigate-imports-line)
(progn (haskell-navigate-imports-goto-end)
(when (haskell-navigate-imports-find-forward-line)
(let ((point (haskell-navigate-imports-find-forward-line)))
(if point
(goto-char point)
(progn (goto-char (point-min))
(if (haskell-navigate-imports-find-forward-line)
(when (search-forward-regexp "^module" nil t 1)
(search-forward "\n\n" nil t 1))))))))
(defun haskell-navigate-imports-goto-end ()
"Skip a bunch of consecutive import lines."
(while (not (or (equal (point)
(not (haskell-navigate-imports-line))))
(defun haskell-navigate-imports-find-forward-line ()
"Return a point with at an import line, or nothing."
(while (not (or (equal (point) (point-max))
(haskell-navigate-imports-after-imports-p) ;; This one just speeds it up.
(if (haskell-navigate-imports-line)
(defun haskell-navigate-imports-line ()
"Try to match the current line as a regexp."
(let ((line (buffer-substring-no-properties (line-beginning-position)
(if (string-match "^import " line)
(defun haskell-navigate-imports-after-imports-p ()
"Are we after the imports list? Just for a speed boost."
(goto-char (line-beginning-position))
(not (not (search-forward-regexp "\\( = \\|\\<instance\\>\\| :: \\)"
(line-end-position) t 1)))))
(provide 'haskell-navigate-imports)
;;; haskell-navigate-imports.el ends here