haskell-mode.el

;;; haskell-mode.el --- A Haskell editing mode    -*- coding: utf-8; lexical-binding: t -*-

;; Copyright © 2003, 2004, 2005, 2006, 2007, 2008, 2016
;;             Free Software Foundation, Inc

;; Copyright © 1992, 1997-1998  Simon Marlow, Graeme E Moss, and Tommy Thorn

;; Author:  1992      Simon Marlow
;;          1997-1998 Graeme E Moss <gem@cs.york.ac.uk> and
;;                    Tommy Thorn <thorn@irisa.fr>,
;;          2001-2002 Reuben Thomas (>=v1.4)
;;          2003      Dave Love <fx@gnu.org>
;;          2016      Arthur Fayzrakhmanov
;; Keywords: faces files Haskell
;; Version: 13.20
;; URL: https://github.com/haskell/haskell-mode

;; This file is not part of GNU Emacs.

;; This file 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, or (at your option)
;; any later version.

;; This file 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/>.

;;; Commentary:

;; A major mode for editing Haskell (the functional programming
;; language, see URL `http://www.haskell.org') in Emacs.
;;
;; Some of its major features include:
;;
;;  - syntax highlighting (font lock),
;;
;;  - automatic indentation,
;;
;;  - on-the-fly documentation,
;;
;;  - interaction with inferior GHCi/Hugs instance,
;;
;;  - scans declarations and places them in a menu.
;;
;; See URL `https://github.com/haskell/haskell-mode' and/or
;; Info node `(haskell-mode)Introduction' for more information.
;;
;; Use `M-x haskell-mode-view-news` (after Haskell Mode is installed)
;; to show information on recent changes in Haskell Mode.

;;; Change Log:

;; This mode is based on an editing mode by Simon Marlow 11/1/92
;; and heavily modified by Graeme E Moss and Tommy Thorn 7/11/98.
;;
;; Version 1.5:
;;   Added autoload for haskell-indentation
;;
;; Version 1.43:
;;   Various tweaks to doc strings and customization support from
;;   Ville Skyttä <scop@xemacs.org>.
;;
;; Version 1.42:
;;   Added autoload for GHCi inferior mode (thanks to Scott
;;   Williams for the bug report and fix).
;;
;; Version 1.41:
;;   Improved packaging, and made a couple more variables
;;   interactively settable.
;;
;; Version 1.4:
;;   Added GHCi mode from Chris Webb, and tidied up a little.
;;
;; Version 1.3:
;;   The literate or non-literate style of a buffer is now indicated
;;   by just the variable haskell-literate: nil, `bird', or `tex'.
;;   For literate buffers with ambiguous style, the value of
;;   haskell-literate-default is used.
;;
;; Version 1.2:
;;   Separated off font locking, declaration scanning and simple
;;   indentation, and made them separate modules.  Modules can be
;;   added easily now.  Support for modules haskell-doc,
;;   haskell-indent, and haskell-hugs.  Literate and non-literate
;;   modes integrated into one mode, and literate buffer indicated by
;;   value of haskell-literate(-bird-style).
;;
;; Version 1.1:
;;   Added support for declaration scanning under XEmacs via
;;   func-menu.  Moved operators to level two fontification.
;;
;; Version 1.0:
;;   Added a nice indention support from Heribert Schuetz
;;   <Heribert.Schuetz@informatik.uni-muenchen.de>:
;;
;;     I have just hacked an Emacs Lisp function which you might prefer
;;     to `indent-relative' in haskell-mode.el.  See below.  It is not
;;     really Haskell-specific because it does not take into account
;;     keywords like `do', `of', and `let' (where the layout rule
;;     applies), but I already find it useful.
;;
;;   Cleaned up the imenu support.  Added support for literate scripts.
;;
;; Version 0.103 [HWL]:
;;   From Hans Wolfgang Loidl <hwloidl@dcs.gla.ac.uk>:
;;
;;   I (HWL) added imenu support by copying the appropriate functions
;;   from hugs-mode.  A menu-bar item "Declarations" is now added in
;;   haskell mode.  The new code, however, needs some clean-up.
;;
;; Version 0.102:
;;
;;   Moved C-c C-c key binding to comment-region.  Leave M-g M-g to do
;;   the work.  comment-start-skip is changed to comply with comment-start.
;;
;; Version 0.101:
;;
;;   Altered indent-line-function to indent-relative.
;;
;; Version 0.100:
;;
;;   First official release.

;;; Code:

(require 'haskell-customize)
(require 'ansi-color)
(require 'dabbrev)
(require 'compile)
(require 'etags)
(require 'flymake)
(require 'outline)
(require 'cl-lib)
(require 'haskell-complete-module)
(require 'haskell-compat)
(require 'haskell-align-imports)
(require 'haskell-lexeme)
(require 'haskell-sort-imports)
(require 'haskell-string)
(require 'haskell-indentation)
(require 'haskell-font-lock)
(require 'haskell-cabal)

;; All functions/variables start with `(literate-)haskell-'.

;; Version of mode.
(defconst haskell-version "13.20"
  "The release version of `haskell-mode'.")

;;;###autoload
(defun haskell-version (&optional here)
  "Show the `haskell-mode` version in the echo area.
With prefix argument HERE, insert it at point."
  (interactive "P")
  (let* ((haskell-mode-dir (ignore-errors
                             (file-name-directory (or (locate-library "haskell-mode") ""))))
         (version (format "haskell-mode version %s (%s)"
                           haskell-version
                           haskell-mode-dir)))
    (if here
        (insert version)
      (message "%s" version))))

;;;###autoload
(defun haskell-mode-view-news ()
  "Display information on recent changes to haskell-mode."
  (interactive)
  (with-current-buffer (find-file-read-only (expand-file-name "NEWS" haskell-mode-pkg-base-dir))
    (goto-char (point-min))
    (outline-hide-sublevels 1)
    (outline-next-visible-heading 1)
    (outline-show-subtree)))

;; Are we looking at a literate script?
(defvar haskell-literate nil
  "If not nil, the current buffer contains a literate Haskell script.
Possible values are: `bird' and `tex', for Bird-style and LaTeX-style
literate scripts respectively.  Set by `haskell-mode' and
`literate-haskell-mode'.  For an ambiguous literate buffer -- i.e. does
not contain either \"\\begin{code}\" or \"\\end{code}\" on a line on
its own, nor does it contain \">\" at the start of a line -- the value
of `haskell-literate-default' is used.")
(make-variable-buffer-local 'haskell-literate)
(put 'haskell-literate 'safe-local-variable 'symbolp)

;; Default literate style for ambiguous literate buffers.
(defcustom haskell-literate-default 'bird
  "Default value for `haskell-literate'.
Used if the style of a literate buffer is ambiguous.  This variable should
be set to the preferred literate style."
  :group 'haskell
  :type '(choice (const bird) (const tex) (const nil)))

(defvar haskell-mode-map
  (let ((map (make-sparse-keymap)))
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;; Editing-specific commands
    (define-key map (kbd "C-c C-.") 'haskell-mode-format-imports)
    (define-key map [remap delete-indentation] 'haskell-delete-indentation)
    (define-key map (kbd "C-c C-l") 'haskell-mode-enable-process-minor-mode)
    (define-key map (kbd "C-c C-b") 'haskell-mode-enable-process-minor-mode)
    (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'.")


(defvar haskell-ghc-supported-extensions
  (split-string (shell-command-to-string "ghc --supported-extensions"))
  "List of language extensions supported by the installed version of GHC.
This list comes from default system's GHC, i.e. first `ghc`
executable found in PATH.")

(defvar haskell-ghc-supported-options
  (split-string (shell-command-to-string "ghc --show-options"))
  "List of options supported by the installed version of GHC.
This list comes from default system's GHC, i.e. first `ghc`
executable found in PATH.")


(defun haskell-mode-enable-process-minor-mode ()
  "Tell the user to choose a minor mode for process interaction."
  (interactive)
  (error "Run `C-h f haskell-mode` for instruction how to setup a Haskell interaction mode."))

(easy-menu-define haskell-mode-menu haskell-mode-map
  "Menu for the Haskell major mode."
  ;; Suggestions from Pupeno <pupeno@pupeno.com>:
  ;; - choose the underlying interpreter
  ;; - look up docs
  `("Haskell"
    ["Indent line" indent-according-to-mode]
    ["(Un)Comment region" comment-region mark-active]
    "---"
    ["Start interpreter" haskell-interactive-switch]
    ["Load file" haskell-process-load-file]
    "---"
    ["Load tidy core" ghc-core-create-core]
    "---"
    ,(if (default-boundp 'eldoc-documentation-function)
         ["Doc mode" eldoc-mode
          :style toggle :selected (bound-and-true-p eldoc-mode)]
       ["Doc mode" haskell-doc-mode
        :style toggle :selected (and (boundp 'haskell-doc-mode) haskell-doc-mode)])
    ["Customize" (customize-group 'haskell)]
    ))

;; Procedurally generated (see Lexeme.hs in ghc).
;; This is a bit unsightly: it's generated by making a list of all
;; unicode characters whose Unicode general category ghc would
;; recognize as valid symbol (or identifier, below) constituent.
(defvar haskell--char-syntax-symbols
  '((161 . 169) 172 (174 . 177) 180 (182 . 184) 191 215 247
    (706 . 709) (722 . 735) (741 . 747) 749 (751 . 767) 885
    894 (900 . 901) 903 1014 1154 (1370 . 1375) (1417 . 1418)
    (1421 . 1423) 1470 1472 1475 1478 (1523 . 1524) (1542 . 1551)
    1563 (1566 . 1567) (1642 . 1645) 1748 1758 1769 (1789 . 1790)
    (1792 . 1805) (2038 . 2041) (2096 . 2110) 2142 (2404 . 2405)
    2416 (2546 . 2547) (2554 . 2555) (2800 . 2801) 2928
    (3059 . 3066) 3199 3449 3572 3647 3663 (3674 . 3675)
    (3841 . 3863) (3866 . 3871) 3892 3894 3896 3973 (4030 . 4037)
    (4039 . 4044) (4046 . 4058) (4170 . 4175) (4254 . 4255)
    4347 (4960 . 4968) (5008 . 5017) 5120 (5741 . 5742)
    (5867 . 5869) (5941 . 5942) (6100 . 6102) (6104 . 6107)
    (6144 . 6154) 6464 (6468 . 6469) (6622 . 6623) (6624 . 6655)
    (6686 . 6687) (6816 . 6822) (6824 . 6829) (7002 . 7018)
    (7028 . 7036) (7164 . 7167) (7227 . 7231) (7294 . 7295)
    (7360 . 7367) 7379 8125 (8127 . 8129) (8141 . 8143)
    (8157 . 8159) (8173 . 8175) (8189 . 8190) (8208 . 8215)
    (8224 . 8231) (8240 . 8248) (8251 . 8260) (8263 . 8286)
    (8314 . 8316) (8330 . 8332) (8352 . 8381) (8448 . 8449)
    (8451 . 8454) (8456 . 8457) 8468 (8470 . 8472) (8478 . 8483)
    8485 8487 8489 8494 (8506 . 8507) (8512 . 8516) (8522 . 8525)
    8527 (8592 . 8703) (8704 . 8959) (8960 . 8967) (8972 . 9000)
    (9003 . 9210) (9216 . 9254) (9280 . 9290) (9372 . 9449)
    (9472 . 9599) (9600 . 9631) (9632 . 9727) (9728 . 9983)
    (9984 . 10087) (10132 . 10175) (10176 . 10180) (10183 . 10213)
    (10224 . 10239) (10240 . 10495) (10496 . 10623) (10624 . 10626)
    (10649 . 10711) (10716 . 10747) (10750 . 10751) (10752 . 11007)
    (11008 . 11123) (11126 . 11157) (11160 . 11193) (11197 . 11208)
    (11210 . 11217) (11493 . 11498) (11513 . 11516) (11518 . 11519)
    11632 (11776 . 11777) (11782 . 11784) 11787 (11790 . 11803)
    (11806 . 11807) (11818 . 11822) (11824 . 11841) (11904 . 11929)
    (11931 . 12019) (12032 . 12245) (12272 . 12283) (12289 . 12292)
    (12306 . 12307) 12316 12320 12336 (12342 . 12343)
    (12349 . 12351) (12443 . 12444) 12448 12539 (12688 . 12689)
    (12694 . 12703) (12736 . 12771) (12800 . 12830) (12842 . 12871)
    12880 (12896 . 12927) (12938 . 12976) (12992 . 13054)
    (13056 . 13311) (19904 . 19967) (42128 . 42182) (42238 . 42239)
    (42509 . 42511) 42611 42622 (42738 . 42743) (42752 . 42774)
    (42784 . 42785) (42889 . 42890) (43048 . 43051) (43062 . 43065)
    (43124 . 43127) (43214 . 43215) (43256 . 43258) (43310 . 43311)
    43359 (43457 . 43469) (43486 . 43487) (43612 . 43615)
    (43639 . 43641) (43742 . 43743) (43760 . 43761) 43867
    44011 64297 (64434 . 64449) (65020 . 65021) (65040 . 65046)
    65049 (65072 . 65076) (65093 . 65094) (65097 . 65103)
    (65104 . 65106) (65108 . 65112) (65119 . 65126) (65128 . 65131)
    (65281 . 65287) (65290 . 65295) (65306 . 65312) 65340
    (65342 . 65344) 65372 65374 65377 (65380 . 65381)
    (65504 . 65510) (65512 . 65518) (65532 . 65533) (65792 . 65794)
    (65847 . 65855) (65913 . 65929) 65932 (65936 . 65947)
    65952 (66000 . 66044) 66463 66512 66927 67671 (67703 . 67704)
    67871 67903 (68176 . 68184) 68223 68296 (68336 . 68342)
    (68409 . 68415) (68505 . 68508) (69703 . 69709) (69819 . 69820)
    (69822 . 69825) (69952 . 69955) (70004 . 70005) (70085 . 70088)
    70093 (70200 . 70205) 70854 (71105 . 71113) (71233 . 71235)
    (74864 . 74868) (92782 . 92783) 92917 (92983 . 92991)
    (92996 . 92997) 113820 113823 (118784 . 119029) (119040 . 119078)
    (119081 . 119140) (119146 . 119148) (119171 . 119172)
    (119180 . 119209) (119214 . 119261) (119296 . 119361)
    119365 (119552 . 119638) 120513 120539 120571 120597
    120629 120655 120687 120713 120745 120771 (126704 . 126705)
    (126976 . 127019) (127024 . 127123) (127136 . 127150)
    (127153 . 127167) (127169 . 127183) (127185 . 127221)
    (127248 . 127278) (127280 . 127339) (127344 . 127386)
    (127462 . 127487) (127488 . 127490) (127504 . 127546)
    (127552 . 127560) (127568 . 127569) (127744 . 127788)
    (127792 . 127869) (127872 . 127950) (127956 . 127991)
    (128000 . 128254) (128256 . 128330) (128336 . 128377)
    (128379 . 128419) (128421 . 128511) (128512 . 128578)
    (128581 . 128591) (128592 . 128639) (128640 . 128719)
    (128736 . 128748) (128752 . 128755) (128768 . 128883)
    (128896 . 128980) (129024 . 129035) (129040 . 129095)
    (129104 . 129113) (129120 . 129159) (129168 . 129197)))

(defvar haskell--char-syntax-identifiers
  '(170
    (178 . 179) 181 (185 . 186) (188 . 190) (192 . 214) (216 . 246)
    (248 . 255) (256 . 383) (384 . 591) (592 . 687) (880 . 883)
    (886 . 887) (891 . 893) 895 902 (904 . 906) 908 (910 . 929) (931 . 1013)
    (1015 . 1023) (1024 . 1153) (1162 . 1279) (1280 . 1327)
    (1329 . 1366) (1377 . 1415) (1488 . 1514) (1520 . 1522) (1568 . 1599)
    (1601 . 1610) (1632 . 1641) (1646 . 1647) (1649 . 1747) 1749
    (1774 . 1788) 1791 1808 (1810 . 1839) (1869 . 1871) (1872 . 1919)
    (1920 . 1957) 1969 (1984 . 2026) (2048 . 2069) (2112 . 2136) (2208 . 2226)
    (2308 . 2361) 2365 2384 (2392 . 2401) (2406 . 2415) (2418 . 2431)
    2432 (2437 . 2444) (2447 . 2448) (2451 . 2472) (2474 . 2480)
    2482 (2486 . 2489) 2493 2510 (2524 . 2525) (2527 . 2529) (2534 . 2545)
    (2548 . 2553) (2565 . 2570) (2575 . 2576) (2579 . 2600)
    (2602 . 2608) (2610 . 2611) (2613 . 2614) (2616 . 2617) (2649 . 2652)
    2654 (2662 . 2671) (2674 . 2676) (2693 . 2701) (2703 . 2705)
    (2707 . 2728) (2730 . 2736) (2738 . 2739) (2741 . 2745) 2749 2768
    (2784 . 2785) (2790 . 2799) (2821 . 2828) (2831 . 2832) (2835 . 2856)
    (2858 . 2864) (2866 . 2867) (2869 . 2873) 2877 (2908 . 2909)
    (2911 . 2913) (2918 . 2927) (2929 . 2935) 2947 (2949 . 2954) (2958 . 2960)
    (2962 . 2965) (2969 . 2970) 2972 (2974 . 2975) (2979 . 2980)
    (2984 . 2986) (2990 . 3001) 3024 (3046 . 3058) (3077 . 3084) (3086 . 3088)
    (3090 . 3112) (3114 . 3129) 3133 (3160 . 3161) (3168 . 3169)
    (3174 . 3183) (3192 . 3198) (3205 . 3212) (3214 . 3216) (3218 . 3240)
    (3242 . 3251) (3253 . 3257) 3261 3294 (3296 . 3297) (3302 . 3311)
    (3313 . 3314) (3333 . 3340) (3342 . 3344) (3346 . 3386) 3389
    3406 (3424 . 3425) (3430 . 3445) (3450 . 3455) (3461 . 3478) (3482 . 3505)
    (3507 . 3515) 3517 (3520 . 3526) (3558 . 3567) (3585 . 3632)
    (3634 . 3635) (3648 . 3653) (3664 . 3673) (3713 . 3714) 3716 (3719 . 3720)
    3722 3725 (3732 . 3735) (3737 . 3743) (3745 . 3747) 3749
    3751 (3754 . 3755) (3757 . 3760) (3762 . 3763) 3773 (3776 . 3780)
    (3792 . 3801) (3804 . 3807) 3840 (3872 . 3891) (3904 . 3911) (3913 . 3948)
    (3976 . 3980) (4096 . 4138) (4159 . 4169) (4176 . 4181)
    (4186 . 4189) 4193 (4197 . 4198) (4206 . 4208) (4213 . 4225) 4238
    (4240 . 4249) (4256 . 4293) 4295 4301 (4304 . 4346) (4349 . 4351)
    (4352 . 4607) (4608 . 4680) (4682 . 4685) (4688 . 4694) 4696 (4698 . 4701)
    (4704 . 4744) (4746 . 4749) (4752 . 4784) (4786 . 4789)
    (4792 . 4798) 4800 (4802 . 4805) (4808 . 4822) (4824 . 4880) (4882 . 4885)
    (4888 . 4954) (4969 . 4988) (4992 . 5007) (5024 . 5108)
    (5121 . 5740) (5743 . 5759) (5761 . 5786) (5792 . 5866) (5873 . 5880)
    (5888 . 5900) (5902 . 5905) (5920 . 5937) (5952 . 5969)
    (5984 . 5996) (5998 . 6000) (6016 . 6067) 6108 (6112 . 6121) (6128 . 6137)
    (6160 . 6169) (6176 . 6210) (6212 . 6263) (6272 . 6312) 6314
    (6320 . 6389) (6400 . 6430) (6470 . 6479) (6480 . 6509) (6512 . 6516)
    (6528 . 6571) (6593 . 6599) (6608 . 6618) (6656 . 6678)
    (6688 . 6740) (6784 . 6793) (6800 . 6809) (6917 . 6963) (6981 . 6987)
    (6992 . 7001) (7043 . 7072) (7086 . 7103) (7104 . 7141)
    (7168 . 7203) (7232 . 7241) (7245 . 7247) (7248 . 7287) (7401 . 7404)
    (7406 . 7409) (7413 . 7414) (7424 . 7467) (7531 . 7543)
    (7545 . 7551) (7552 . 7578) (7680 . 7935) (7936 . 7957) (7960 . 7965)
    (7968 . 8005) (8008 . 8013) (8016 . 8023) 8025 8027 8029
    (8031 . 8061) (8064 . 8116) (8118 . 8124) 8126 (8130 . 8132) (8134 . 8140)
    (8144 . 8147) (8150 . 8155) (8160 . 8172) (8178 . 8180)
    (8182 . 8188) 8304 (8308 . 8313) (8320 . 8329) 8450 8455 (8458 . 8467)
    8469 (8473 . 8477) 8484 8486 8488 (8490 . 8493) (8495 . 8505)
    (8508 . 8511) (8517 . 8521) 8526 (8528 . 8543) (8579 . 8580)
    8585 (9312 . 9371) (9450 . 9471) (10102 . 10131) (11264 . 11310)
    (11312 . 11358) (11360 . 11387) (11390 . 11391) (11392 . 11492)
    (11499 . 11502) (11506 . 11507) 11517 (11520 . 11557) 11559 11565
    (11568 . 11623) (11648 . 11670) (11680 . 11686) (11688 . 11694)
    (11696 . 11702) (11704 . 11710) (11712 . 11718) (11720 . 11726)
    (11728 . 11734) (11736 . 11742) 12294 12348 (12353 . 12438) 12447
    (12449 . 12538) 12543 (12549 . 12589) (12593 . 12686) (12690 . 12693)
    (12704 . 12730) (12784 . 12799) (12832 . 12841) (12872 . 12879)
    (12881 . 12895) (12928 . 12937) (12977 . 12991) (13312 . 19893)
    (19968 . 40908) (40960 . 40980) (40982 . 42124) (42192 . 42231)
    (42240 . 42507) (42512 . 42539) (42560 . 42606) (42624 . 42651)
    (42656 . 42725) (42786 . 42863) (42865 . 42887) (42891 . 42894)
    (42896 . 42925) (42928 . 42929) 42999 (43002 . 43007)
    (43008 . 43009) (43011 . 43013) (43015 . 43018) (43020 . 43042)
    (43056 . 43061) (43072 . 43123) (43138 . 43187) (43216 . 43225)
    (43250 . 43255) 43259 (43264 . 43301) (43312 . 43334) (43360 . 43388)
    (43396 . 43442) (43472 . 43481) (43488 . 43492) (43495 . 43518)
    (43520 . 43560) (43584 . 43586) (43588 . 43595) (43600 . 43609)
    (43616 . 43631) (43633 . 43638) 43642 (43646 . 43647)
    (43648 . 43695) 43697 (43701 . 43702) (43705 . 43709) 43712 43714
    (43739 . 43740) (43744 . 43754) 43762 (43777 . 43782) (43785 . 43790)
    (43793 . 43798) (43808 . 43814) (43816 . 43822) (43824 . 43866)
    (43876 . 43877) (43968 . 44002) (44016 . 44025) (44032 . 55203)
    (55216 . 55238) (55243 . 55291) (63744 . 64109) (64112 . 64217)
    (64256 . 64262) (64275 . 64279) 64285 (64287 . 64296)
    (64298 . 64310) (64312 . 64316) 64318 (64320 . 64321) (64323 . 64324)
    (64326 . 64335) (64336 . 64433) (64467 . 64829) (64848 . 64911)
    (64914 . 64967) (65008 . 65019) (65136 . 65140) (65142 . 65276)
    (65296 . 65305) (65313 . 65338) (65345 . 65370) (65382 . 65391)
    (65393 . 65437) (65440 . 65470) (65474 . 65479) (65482 . 65487)
    (65490 . 65495) (65498 . 65500) (65536 . 65547) (65549 . 65574)
    (65576 . 65594) (65596 . 65597) (65599 . 65613) (65616 . 65629)
    (65664 . 65786) (65799 . 65843) (65909 . 65912) (65930 . 65931)
    (66176 . 66204) (66208 . 66256) (66273 . 66299) (66304 . 66339)
    (66352 . 66368) (66370 . 66377) (66384 . 66421) (66432 . 66461)
    (66464 . 66499) (66504 . 66511) (66560 . 66639) (66640 . 66687)
    (66688 . 66717) (66720 . 66729) (66816 . 66855) (66864 . 66915)
    (67072 . 67382) (67392 . 67413) (67424 . 67431) (67584 . 67589)
    67592 (67594 . 67637) (67639 . 67640) 67644 67647 (67648 . 67669)
    (67672 . 67679) (67680 . 67702) (67705 . 67711) (67712 . 67742)
    (67751 . 67759) (67840 . 67867) (67872 . 67897) (67968 . 67999)
    (68000 . 68023) (68030 . 68031) 68096 (68112 . 68115)
    (68117 . 68119) (68121 . 68147) (68160 . 68167) (68192 . 68222)
    (68224 . 68255) (68288 . 68295) (68297 . 68324) (68331 . 68335)
    (68352 . 68405) (68416 . 68437) (68440 . 68447) (68448 . 68466)
    (68472 . 68479) (68480 . 68497) (68521 . 68527) (68608 . 68680)
    (69216 . 69246) (69635 . 69687) (69714 . 69743) (69763 . 69807)
    (69840 . 69864) (69872 . 69881) (69891 . 69926) (69942 . 69951)
    (69968 . 70002) 70006 (70019 . 70066) (70081 . 70084) (70096 . 70106)
    (70113 . 70132) (70144 . 70161) (70163 . 70187) (70320 . 70366)
    (70384 . 70393) (70405 . 70412) (70415 . 70416) (70419 . 70440)
    (70442 . 70448) (70450 . 70451) (70453 . 70457) 70461
    (70493 . 70497) (70784 . 70831) (70852 . 70853) 70855 (70864 . 70873)
    (71040 . 71086) (71168 . 71215) 71236 (71248 . 71257)
    (71296 . 71338) (71360 . 71369) (71840 . 71922) 71935 (72384 . 72440)
    (73728 . 74648) (77824 . 78894) (92160 . 92728) (92736 . 92766)
    (92768 . 92777) (92880 . 92909) (92928 . 92975) (93008 . 93017)
    (93019 . 93025) (93027 . 93047) (93053 . 93071) (93952 . 94020)
    94032 (110592 . 110593) (113664 . 113770) (113776 . 113788)
    (113792 . 113800) (113808 . 113817) (119648 . 119665) (119808 . 119892)
    (119894 . 119964) (119966 . 119967) 119970 (119973 . 119974)
    (119977 . 119980) (119982 . 119993) 119995 (119997 . 120003)
    (120005 . 120069) (120071 . 120074) (120077 . 120084)
    (120086 . 120092) (120094 . 120121) (120123 . 120126) (120128 . 120132)
    120134 (120138 . 120144) (120146 . 120485) (120488 . 120512)
    (120514 . 120538) (120540 . 120570) (120572 . 120596)
    (120598 . 120628) (120630 . 120654) (120656 . 120686) (120688 . 120712)
    (120714 . 120744) (120746 . 120770) (120772 . 120779)
    (120782 . 120831) (124928 . 125124) (125127 . 125135) (126464 . 126467)
    (126469 . 126495) (126497 . 126498) 126500 126503 (126505 . 126514)
    (126516 . 126519) 126521 126523 126530 126535 126537
    126539 (126541 . 126543) (126545 . 126546) 126548 126551 126553
    126555 126557 126559 (126561 . 126562) 126564 (126567 . 126570)
    (126572 . 126578) (126580 . 126583) (126585 . 126588) 126590 (126592 . 126601)
    (126603 . 126619) (126625 . 126627) (126629 . 126633)
    (126635 . 126651) (127232 . 127244) (131072 . 173782) (173824 . 177972)
    (177984 . 178205) (194560 . 195101)))


;; Syntax table.
(defvar haskell-mode-syntax-table
  (let ((table (make-syntax-table)))
    (modify-syntax-entry ?\  " " table)
    (modify-syntax-entry ?\t " " table)
    (modify-syntax-entry ?\" "\"" table)
    (modify-syntax-entry ?\' "_" table)
    (modify-syntax-entry ?_  "w" table)
    (modify-syntax-entry ?\( "()" table)
    (modify-syntax-entry ?\) ")(" table)
    (modify-syntax-entry ?\[  "(]" table)
    (modify-syntax-entry ?\]  ")[" table)

    (modify-syntax-entry ?\{  "(}1nb" table)
    (modify-syntax-entry ?\}  "){4nb" table)
    (modify-syntax-entry ?-  ". 123" table)
    (modify-syntax-entry ?\n ">" table)

    (modify-syntax-entry ?\` "$`" table)

    (mapc (lambda (x)
            (modify-syntax-entry x "." table))
          "!#$%&*+./:<=>?@^|~,;\\")

    ;; Haskell symbol characters are treated as punctuation because
    ;; they are not able to form identifiers with word constituent 'w'
    ;; class characters.
    (dolist (charcodes haskell--char-syntax-symbols)
      (modify-syntax-entry charcodes "." table))
    ;; ... and for identifier characters
    (dolist (charcodes haskell--char-syntax-identifiers)
      (modify-syntax-entry charcodes "w" table))

    table)
  "Syntax table used in Haskell mode.")

(defun haskell-syntax-propertize (begin end)
  (save-excursion
    (when haskell-literate
      (goto-char begin)
      ;; Algorithm (first matching rule wins):
      ;; - current line is latex code if previous non-empty line was
      ;;   latex code or was \begin{code} and current line is not
      ;;   \end{code}
      ;; - current line is bird code if it starts with >
      ;; - else literate comment
      (let ((previous-line-latex-code
             (catch 'return
               (save-excursion
                 (when (= (forward-line -1) 0)
                   (while (looking-at-p "^[\t ]*$")
                     (unless (= (forward-line -1) 0)
                       (throw 'return nil)))
                   (or
                    (and
                     (not (equal (string-to-syntax "<") (syntax-after (point))))
                     (not (looking-at-p "^>")))
                    (looking-at-p "^\\\\begin{code}[\t ]*$")))))))
        (while (< (point) end)
          (unless (looking-at-p "^[\t ]*$")
            (if previous-line-latex-code
                (if (looking-at-p "^\\\\end{code}[\t ]*$")
                    (progn
                      (put-text-property (point) (1+ (point)) 'syntax-table (string-to-syntax "<"))
                      (setq previous-line-latex-code nil))
                  ;; continue latex-code
                  )
              (if (looking-at-p "^>")
                  ;; this is a whitespace
                  (put-text-property (point) (1+ (point)) 'syntax-table (string-to-syntax "-"))
                ;; this is a literate comment
                (progn
                  (put-text-property (point) (1+ (point)) 'syntax-table (string-to-syntax "<"))
                  (when (looking-at-p "^\\\\begin{code}[\t ]*$")
                    (setq previous-line-latex-code t))))))
          (forward-line 1))))

    (goto-char begin)
    (let ((ppss (syntax-ppss)))
      (when (nth 8 ppss)
        ;; go to the beginning of a comment or string
        (goto-char (nth 8 ppss))
        (when (equal ?| (nth 3 ppss))
          ;; if this is a quasi quote we need to backtrack even more
          ;; to the opening bracket
          (skip-chars-backward "^[")
          (goto-char (1- (point)))))

      (while (< (point) end)
        (let
            ((token-kind (haskell-lexeme-looking-at-token)))

          (cond
           ((equal token-kind 'qsymid)
            (when (member
                   (haskell-lexeme-classify-by-first-char (char-after (match-beginning 1)))
                   '(varsym consym))
              ;; we have to neutralize potential comments here
              (put-text-property (match-beginning 1) (match-end 1) 'syntax-table (string-to-syntax "."))))
           ((equal token-kind 'number)
            (put-text-property (match-beginning 0) (match-end 0) 'syntax-table (string-to-syntax "w")))
           ((equal token-kind 'char)
            (put-text-property (match-beginning 0) (1+ (match-beginning 0)) 'syntax-table (string-to-syntax "\""))
            (put-text-property (1- (match-end 0)) (match-end 0) 'syntax-table (string-to-syntax "\"")))
           ((equal token-kind 'string)
            (save-excursion
              (goto-char (match-beginning 2))
              (let ((limit (match-end 2)))
                (save-match-data
                  (while (re-search-forward "\"" limit t)
                    (put-text-property (match-beginning 0) (match-end 0) 'syntax-table (string-to-syntax ".")))))
              ;; Place a generic string delimeter only when an open
              ;; quote is closed by end-of-line Emacs acts strangely
              ;; when a generic delimiter is not closed so in case
              ;; string ends at the end of the buffer we will use
              ;; plain string
              (when (and (equal (match-beginning 3) (match-end 3))
                         (not (equal (match-beginning 3) (point-max))))
                (put-text-property (match-beginning 1) (match-end 1) 'syntax-table (string-to-syntax "|"))
                (put-text-property (match-beginning 3) (1+ (match-end 3)) 'syntax-table (string-to-syntax "|")))))
           ((equal token-kind 'template-haskell-quasi-quote)
            (put-text-property (match-beginning 2) (match-end 2) 'syntax-table (string-to-syntax "\""))
            (put-text-property (match-beginning 4) (match-end 4) 'syntax-table (string-to-syntax "\""))
            (save-excursion
              (goto-char (match-beginning 3))
              (let ((limit (match-end 3)))
                (save-match-data
                  (while (re-search-forward "\"" limit t)
                    (put-text-property (match-beginning 0) (match-end 0) 'syntax-table (string-to-syntax "."))))))))
          (if token-kind
              (goto-char (match-end 0))
            (goto-char end)))))))

(defun haskell-ident-at-point ()
  "Return the identifier near point going backward or nil if none found.
May return a qualified name."
  (let ((reg (haskell-ident-pos-at-point)))
    (when reg
      (buffer-substring-no-properties (car reg) (cdr reg)))))

(defun haskell-spanable-pos-at-point ()
  "Like `haskell-ident-pos-at-point', but includes any surrounding backticks."
  (save-excursion
    (let ((pos (haskell-ident-pos-at-point)))
      (when pos
        (cl-destructuring-bind (start . end) pos
          (if (and (eq ?` (char-before start))
                   (eq ?` (char-after end)))
              (cons (- start 1) (+ end 1))
            (cons start end)))))))

(defun haskell-ident-pos-at-point ()
  "Return the span of the identifier near point going backward.
Returns nil if no identifier found or point is inside string or
comment.  May return a qualified name."
  (when (not (nth 8 (syntax-ppss)))
    ;; Do not handle comments and strings
    (let (start end)
      ;; Initial point position is non-deterministic, it may occur anywhere
      ;; inside identifier span, so the approach is:
      ;; - first try go left and find left boundary
      ;; - then try go right and find right boundary
      ;;
      ;; In both cases assume the longest path, e.g. when going left take into
      ;; account than point may occur at the end of identifier, when going right
      ;; take into account that point may occur at the beginning of identifier.
      ;;
      ;; We should handle `.` character very careful because it is heavily
      ;; overloaded.  Examples of possible cases:
      ;; Control.Monad.>>=  -- delimiter
      ;; Control.Monad.when -- delimiter
      ;; Data.Aeson..:      -- delimiter and operator symbol
      ;; concat.map         -- composition function
      ;; .?                 -- operator symbol
      (save-excursion
        ;; First, skip whitespace if we're on it, moving point to last
        ;; identifier char.  That way, if we're at "map ", we'll see the word
        ;; "map".
        (when (and (looking-at (rx eol))
                   (not (bolp)))
          (backward-char))
        (when (and (not (eobp))
                   (eq (char-syntax (char-after)) ? ))
          (skip-chars-backward " \t")
          (backward-char))
        ;; Now let's try to go left.
        (save-excursion
          (if (not (haskell-mode--looking-at-varsym))
              ;; Looking at non-operator char, this is quite simple
              (progn
                (skip-syntax-backward "w_")
                ;; Remember position
                (setq start (point)))
            ;; Looking at operator char.
            (while (and (not (bobp))
                        (haskell-mode--looking-at-varsym))
              ;; skip all operator chars backward
              (setq start (point))
              (backward-char))
            ;; Extra check for case when reached beginning of the buffer.
            (when (haskell-mode--looking-at-varsym)
              (setq start (point))))
          ;; Slurp qualification part if present.  If identifier is qualified in
          ;; case of non-operator point will stop before `.` dot, but in case of
          ;; operator it will stand at `.` delimiting dot.  So if we're looking
          ;; at `.` let's step one char forward and try to get qualification
          ;; part.
          (goto-char start)
          (when (looking-at-p (rx "."))
            (forward-char))
          (let ((pos (haskell-mode--skip-qualification-backward)))
            (when pos
              (setq start pos))))
        ;; Finally, let's try to go right.
        (save-excursion
          ;; Try to slurp qualification part first.
          (skip-syntax-forward "w_")
          (setq end (point))
          (while (and (looking-at (rx "." upper))
                      (not (zerop (progn (forward-char)
                                         (skip-syntax-forward "w_")))))
            (setq end (point)))
          ;; If point was at non-operator we already done, otherwise we need an
          ;; extra check.
          (while (haskell-mode--looking-at-varsym)
            (forward-char)
            (setq end (point))))
        (when (not (= start end))
          (cons start end))))))

(defun haskell-mode--looking-at-varsym ()
  "Return t when point stands at operator symbol."
  (when (not (eobp))
    (let ((lex (haskell-lexeme-classify-by-first-char (char-after))))
      (or (eq lex 'varsym)
          (eq lex 'consym)))))

(defun haskell-mode--skip-qualification-backward ()
  "Skip qualified part of identifier backward.
Expects point stands *after* delimiting dot.
Returns beginning position of qualified part or nil if no qualified part found."
  (when (not (and (bobp)
                  (looking-at (rx bol))))
    (let ((case-fold-search nil)
          pos)
      (while (and (eq (char-before) ?.)
                  (progn (backward-char)
                         (not (zerop (skip-syntax-backward "w'"))))
                  (skip-syntax-forward "'")
                  (looking-at "[[:upper:]]"))
        (setq pos (point)))
      pos)))

(defun haskell-delete-indentation (&optional arg)
  "Like `delete-indentation' but ignoring Bird-style \">\"."
  (interactive "*P")
  (let ((fill-prefix (or fill-prefix (if (eq haskell-literate 'bird) ">"))))
    (delete-indentation arg)))

(defvar eldoc-print-current-symbol-info-function)

;; The main mode functions
;;;###autoload
(define-derived-mode haskell-mode prog-mode "Haskell"
  "Major mode for editing Haskell programs.

For more information see also Info node `(haskell-mode)Getting Started'.

\\<haskell-mode-map>

Literate Haskell scripts are supported via `literate-haskell-mode'.
The variable `haskell-literate' indicates the style of the script in the
current buffer.  See the documentation on this variable for more details.

Use `haskell-version' to find out what version of Haskell mode you are
currently using.

Additional Haskell mode modules can be hooked in via `haskell-mode-hook'.

Indentation modes:

    `haskell-indentation-mode', Kristof Bastiaensen, Gergely Risko
      Intelligent semi-automatic indentation Mk2

    `haskell-indent-mode', Guy Lapalme
      Intelligent semi-automatic indentation.

Interaction modes:

    `interactive-haskell-mode'
      Interact with per-project GHCi processes through a REPL and
      directory-aware sessions.

    `inf-haskell-mode'
      Interact with a GHCi process using comint-mode. Deprecated.

Other modes:

    `haskell-decl-scan-mode', Graeme E Moss
      Scans top-level declarations, and places them in a menu.

    `haskell-doc-mode', Hans-Wolfgang Loidl
      Echoes types of functions or syntax of keywords when the cursor is idle.

To activate a minor-mode, simply run the interactive command. For
example, `M-x haskell-doc-mode'. Run it again to disable it.

To enable a mode for every haskell-mode buffer, add a hook in
your Emacs configuration. To do that you can customize
`haskell-mode-hook' or add lines to your .emacs file. For
example, to enable `interactive-haskell-mode', use the following:

    (add-hook 'haskell-mode-hook 'interactive-haskell-mode)

For more details see Info node `(haskell-mode)haskell-mode-hook'.

Minor modes that work well with `haskell-mode':

- `smerge-mode': show and work with diff3 conflict markers used
  by git, svn and other version control systems."
  :group 'haskell
  (when (< emacs-major-version 24)
    (error "haskell-mode requires at least Emacs 24"))

  ;; paragraph-{start,separate} should treat comments as paragraphs as well.
  (set (make-local-variable 'paragraph-start)
       (concat " *{-\\| *-- |\\|" page-delimiter))
  (set (make-local-variable 'paragraph-separate)
       (concat " *$\\| *\\({-\\|-}\\) *$\\|" page-delimiter))
  (set (make-local-variable 'fill-paragraph-function) 'haskell-fill-paragraph)
  ;; (set (make-local-variable 'adaptive-fill-function) 'haskell-adaptive-fill)
  (set (make-local-variable 'adaptive-fill-mode) nil)
  (set (make-local-variable 'comment-start) "-- ")
  (set (make-local-variable 'comment-padding) 0)
  (set (make-local-variable 'comment-start-skip) "[-{]-[ \t]*")
  (set (make-local-variable 'comment-end) "")
  (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 'syntax-propertize-function) #'haskell-syntax-propertize)

  ;; Set things up for eldoc-mode.
  (set (make-local-variable 'eldoc-documentation-function)
       'haskell-doc-current-info)
  ;; Set things up for imenu.
  (set (make-local-variable 'imenu-create-index-function)
       'haskell-ds-create-imenu-index)
  ;; Set things up for font-lock.
  (set (make-local-variable 'font-lock-defaults)
       '((haskell-font-lock-keywords)
         nil nil nil nil
         (font-lock-syntactic-face-function
          . haskell-syntactic-face-function)
         ;; Get help from font-lock-syntactic-keywords.
         (parse-sexp-lookup-properties . t)
         (font-lock-extra-managed-props . (composition haskell-type))))
  ;; Haskell's layout rules mean that TABs have to be handled with extra care.
  ;; The safer option is to avoid TABs.  The second best is to make sure
  ;; TABs stops are 8 chars apart, as mandated by the Haskell Report.  --Stef
  (set (make-local-variable 'indent-tabs-mode) nil)
  (set (make-local-variable 'tab-width) 8)
  (set (make-local-variable 'comment-auto-fill-only-comments) t)
  ;; Haskell is not generally suitable for electric indentation, since
  ;; there is no unambiguously correct indent level for any given line.
  (when (boundp 'electric-indent-inhibit)
    (setq electric-indent-inhibit t))

  ;; dynamic abbrev support: recognize Haskell identifiers
  ;; Haskell is case-sensitive language
  (set (make-local-variable 'dabbrev-case-fold-search) nil)
  (set (make-local-variable 'dabbrev-case-distinction) nil)
  (set (make-local-variable 'dabbrev-case-replace) nil)
  (set (make-local-variable 'dabbrev-abbrev-char-regexp) "\\sw\\|[.]")
  (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)
  ;; provide non-interactive completion function
  (add-hook 'completion-at-point-functions
            #'haskell-completions-completion-at-point
            nil
            t)
  (haskell-indentation-mode))

(defun haskell-fill-paragraph (justify)
  (save-excursion
    ;; Fill paragraph should only work in comments.
    ;; The -- comments are handled properly by default
    ;; The {- -} comments need some extra love.
    (let* ((syntax-values (syntax-ppss))
           (comment-num (nth 4 syntax-values)))
      (cond
       ((eq t comment-num)
        ;; standard fill works wonders inside a non-nested comment
        (fill-comment-paragraph justify))

       ((integerp comment-num)
        ;; we are in a nested comment. lets narrow to comment content
        ;; and use plain paragraph fill for that
        (let* ((comment-start-point (nth 8 syntax-values))
               (comment-end-point
                (save-excursion
                  (goto-char comment-start-point)
                  (forward-sexp)
                  ;; Find end of any comment even if forward-sexp
                  ;; fails to find the right braces.
                  (backward-char 3)
                  (re-search-forward "[ \t]?-}" nil t)
                  (match-beginning 0)))
               (fill-start (+ 2 comment-start-point))
               (fill-end comment-end-point)
               (fill-paragraph-handle-comment nil))
          (save-restriction
            (narrow-to-region fill-start fill-end)
            (fill-paragraph justify)
            ;; If no filling happens, whatever called us should not
            ;; continue with standard text filling, so return t
            t)))
       ((eolp)
        ;; do nothing outside of a comment
        t)
       (t
        ;; go to end of line and try again
        (end-of-line)
        (haskell-fill-paragraph justify))))))


;; (defun haskell-adaptive-fill ()
;;   ;; We want to use "--  " as the prefix of "-- |", etc.
;;   (let* ((line-end (save-excursion (end-of-line) (point)))
;;          (line-start (point)))
;;     (save-excursion
;;       (unless (in-comment)
;;         ;; Try to find the start of a comment. We only fill comments.
;;         (search-forward-regexp comment-start-skip line-end t))
;;       (when (in-comment)
;;         (let ();(prefix-start (point)))
;;           (skip-syntax-forward "^w")
;;           (make-string (- (point) line-start) ?\s))))))

;;;###autoload
(defun haskell-forward-sexp (&optional arg)
  "Haskell specific version of `forward-sexp'.

Move forward across one balanced expression (sexp).  With ARG, do
it that many times.  Negative arg -N means move backward across N
balanced expressions.  This command assumes point is not in a
string or comment.

If unable to move over a sexp, signal `scan-error' with three
arguments: a message, the start of the obstacle (a parenthesis or
list marker of some kind), and end of the obstacle."
  (interactive "^p")
  (or arg (setq arg 1))
  (if (< arg 0)
      (while (< arg 0)
        (skip-syntax-backward "->")
        ;; Navigate backwards using plain `backward-sexp', assume that it
        ;; skipped over at least one Haskell expression, and jump forward until
        ;; last possible point before the starting position. If applicable,
        ;; `scan-error' is signalled by `backward-sexp'.
        (let ((end (point))
              (forward-sexp-function nil))
          (backward-sexp)
          (let ((cur (point)))
            (while (< (point) end)
              (setf cur (point))
              (haskell-forward-sexp)
              (skip-syntax-forward "->"))
            (goto-char cur)))
        (setf arg (1+ arg)))
    (save-match-data
      (while (> arg 0)
        (when (haskell-lexeme-looking-at-token)
          (cond ((member (match-string 0) (list "(" "[" "{"))
                 (goto-char (or (scan-sexps (point) 1) (buffer-end 1))))
                ((member (match-string 0) (list ")" "]" "}"))
                 (signal 'scan-error (list "Containing expression ends prematurely."
                                           (match-beginning 0)
                                           (match-end 0))))
                (t (goto-char (match-end 0)))))
        (setf arg (1- arg))))))



;;;###autoload
(define-derived-mode literate-haskell-mode haskell-mode "LitHaskell"
  "As `haskell-mode' but for literate scripts."
  (setq haskell-literate
        (save-excursion
          (goto-char (point-min))
          (cond
           ((re-search-forward "^\\\\\\(begin\\|end\\){code}$" nil t) 'tex)
           ((re-search-forward "^>" nil t) 'bird)
           (t haskell-literate-default))))
  (if (eq haskell-literate 'bird)
      ;; fill-comment-paragraph isn't much use there, and even gets confused
      ;; by the syntax-table text-properties we add to mark the first char
      ;; of each line as a comment-starter.
      (set (make-local-variable 'fill-paragraph-handle-comment) nil))
  (set (make-local-variable 'mode-line-process)
       '("/" (:eval (symbol-name haskell-literate)))))

;;;###autoload
(add-to-list 'auto-mode-alist        '("\\.[gh]s\\'" . haskell-mode))
;;;###autoload
(add-to-list 'auto-mode-alist        '("\\.l[gh]s\\'" . literate-haskell-mode))
;;;###autoload
(add-to-list 'auto-mode-alist        '("\\.hsc\\'" . haskell-mode))
;;;###autoload
(add-to-list 'interpreter-mode-alist '("runghc" . haskell-mode))
;;;###autoload
(add-to-list 'interpreter-mode-alist '("runhaskell" . haskell-mode))
;;;###autoload
(add-to-list 'completion-ignored-extensions ".hi")


(defcustom haskell-check-command "hlint"
  "*Command used to check a Haskell file."
  :group 'haskell
  :type '(choice (const "hlint")
                 (const "ghc -fno-code")
                 (string :tag "Other command")))

(defcustom haskell-tags-on-save nil
  "Generate tags via hasktags after saving."
  :group 'haskell
  :type 'boolean)

(defvar haskell-saved-check-command nil
  "Internal use.")

(defcustom haskell-indent-spaces 2
  "Number of spaces to indent inwards."
  :group 'haskell
  :type 'integer)

;; Like Python.  Should be abstracted, sigh.
(defun haskell-check (command)
  "Check a Haskell file (default current buffer's file).
Runs COMMAND, a shell command, as if by `compile'.
See `haskell-check-command' for the default."
  (interactive
   (list (read-string "Checker command: "
                      (or haskell-saved-check-command
                          (concat haskell-check-command " "
                                  (let ((name (buffer-file-name)))
                                    (if name
                                        (file-name-nondirectory name))))))))
  (setq haskell-saved-check-command command)
  (save-some-buffers (not compilation-ask-about-save) nil)
  (compilation-start command))

(defun haskell-flymake-init ()
  "Flymake init function for Haskell.
To be added to `flymake-init-create-temp-buffer-copy'."
  (let ((checker-elts (and haskell-saved-check-command
                           (split-string haskell-saved-check-command))))
    (list (car checker-elts)
          (append (cdr checker-elts)
                  (list (flymake-init-create-temp-buffer-copy
                         'flymake-create-temp-inplace))))))

(add-to-list 'flymake-allowed-file-name-masks '("\\.l?hs\\'" haskell-flymake-init))

(defun haskell-mode-format-imports ()
  "Format the imports by aligning and sorting them."
  (interactive)
  (let ((col (current-column)))
    (haskell-sort-imports)
    (haskell-align-imports)
    (goto-char (+ (line-beginning-position)
                  col))))

(defun haskell-mode-before-save-handler ()
  "Function that will be called before buffer's saving."
  )

;; 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-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]\\|$")
          ;; 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)
                                    (looking-at "[ \t]")))
          (insert " "))
        (insert "{-# SCC \"\" #-}")
        (unless space-at-point
          (insert " "))
        (forward-char (if space-at-point -5 -6))
        t )))

(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")))

(make-obsolete
 'haskell-mode-insert-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
successful, nil otherwise."
  (save-excursion
    (let ((old-point (point))
          (scc "\\({-#[ \t]*SCC \"[^\"]*\"[ \t]*#-}\\)[ \t]*"))
      (while (not (or (looking-at scc) (bolp)))
        (forward-char -1))
      (if (and (looking-at scc)
               (<= (match-beginning 1) old-point)
               (> (match-end 1) old-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")))

(make-obsolete
 'haskell-mode-kill-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."
  (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."
  (interactive)
  (let ((components (cl-loop for part
                             in (reverse (split-string (buffer-file-name) "/"))
                             while (let ((case-fold-search nil))
                                     (string-match "^[A-Z]+" part))
                             collect (replace-regexp-in-string "\\.l?hs$" "" part))))
    (mapconcat 'identity (reverse components) ".")))

(defvar haskell-auto-insert-module-format-string
  "-- | \n\nmodule %s where\n\n"
  "Template string that will be inserted in new haskell buffers via `haskell-auto-insert-module-template'.")

(defun haskell-auto-insert-module-template ()
  "Insert a module template for the newly created buffer."
  (interactive)
  (when (and (= (point-min)
                (point-max))
             (buffer-file-name))
    (insert (format haskell-auto-insert-module-format-string (haskell-guess-module-name)))
    (goto-char (point-min))
    (end-of-line)))

;;;###autoload
(defun haskell-mode-generate-tags (&optional and-then-find-this-tag)
  "Generate tags using Hasktags.  This is synchronous function.

If optional AND-THEN-FIND-THIS-TAG argument is present it is used
with function `xref-find-definitions' after new table was
generated."
  (let* ((dir (haskell-cabal--find-tags-dir))
         (command (haskell-cabal--compose-hasktags-command dir)))
    (if (not command)
        (error "Unable to compose hasktags command")
      (shell-command command)
      (haskell-mode-message-line "Tags generated.")
      (when and-then-find-this-tag
        (let ((tags-file-name dir))
          (xref-find-definitions and-then-find-this-tag))))))

(defun haskell-mode-message-line (str)
  "Echo STR in mini-buffer.
Given string is shrinken to single line, multiple lines just
disturbs the programmer."
  (message (haskell-mode-one-line str (frame-width))))

(defun haskell-mode-one-line (str width)
  "Try to fit STR as much as possible on one line according to given WIDTH."
  (let* ((long-line (replace-regexp-in-string "\n" " " str))
         (condensed  (replace-regexp-in-string
                      " +" " " (haskell-string-trim long-line))))
    (truncate-string-to-width condensed width nil nil "…")))

;; Provide ourselves:
(provide 'haskell-mode)
;;; haskell-mode.el ends here