;; coq.el --- Major mode for Coq proof assistant  -*- coding: utf-8 -*-
;; Copyright (C) 1994-2009 LFCS Edinburgh.
;; Authors: Healfdene Goguen, Pierre Courtieu
;; License:     GPL (GNU GENERAL PUBLIC LICENSE)
;; Maintainer: Pierre Courtieu <Pierre.Courtieu@cnam.fr>
;;
;; $Id$



(eval-when-compile
  (require 'cl)
  (require 'proof-compat))

(eval-when (compile)
  (require 'proof-utils)
  (require 'span)
  (require 'outline)
  (require 'newcomment)
  (require 'etags)
  (unless (proof-try-require 'smie)
    (defvar smie-indent-basic nil)
    (defvar smie-rules-function nil))
  (defvar proof-info nil)       ; dynamic scope in proof-tree-urgent-action
  (defvar action nil)       ; dynamic scope in coq-insert-as stuff
  (defvar string nil)       ; dynamic scope in coq-insert-as stuff
  (defvar coq-auto-insert-as nil)    ; defpacustom
  (defvar coq-time-commands nil)        ; defpacustom
  (defvar coq-use-project-file t)        ; defpacustom
  (defvar coq-use-editing-holes nil)    ; defpacustom
  (defvar coq-hide-additional-subgoals nil) ; defpacustom
  (proof-ready-for-assistant 'coq))     ; compile for coq

(require 'proof)
(require 'coq-system)                   ; load path, option, project file etc.
(require 'coq-syntax)                   ; font-lock, syntax categories (tactics, commands etc)
(require 'coq-local-vars)               ; setting coq args via file variables 
                                        ;   (prefer _CoqProject file instead)
(require 'coq-abbrev)                   ; abbrev and coq specific menu
(require 'coq-seq-compile)              ; sequential compilation of Requires
(require 'coq-par-compile)              ; parallel compilation of Requires


;; for compilation in Emacs < 23.3 (NB: declare function only works at top level)
(declare-function smie-bnf->prec2 "smie")
(declare-function smie-rule-parent-p "smie")
(declare-function smie-default-forward-token "smie")
(declare-function smie-default-backward-token "smie")
(declare-function smie-rule-prev-p "smie")
(declare-function smie-rule-separator "smie")
(declare-function smie-rule-parent "smie")

(declare-function some "cl-extra")      ; spurious bytecomp warning

;; prettify is in emacs > 24.4
;; FIXME: this should probably be done like for smie above.
(defvar coq-may-use-prettify nil) ; may become t below
(eval-when-compile
  (if (fboundp 'prettify-symbols-mode)
      (defvar coq-may-use-prettify t)
    (defvar prettify-symbols-alist nil)))


;; ----- coq-shell configuration options

;;; Code:
;; debugging functions
;; (defun proofstack () (coq-get-span-proofstack (span-at (point) 'type)))
(defvar coq-debug nil)
;; End debugging

;; Obsolete
;;(defcustom coq-default-undo-limit 500
;;  "Maximum number of Undo's possible when doing a proof."
;;  :type 'number
;;  :group 'coq)

(defcustom coq-user-init-cmd nil
  "user defined init commands for Coq.
These are appended at the end of `coq-shell-init-cmd'."
  :type '(repeat (cons (string :tag "command")))
  :group 'coq)

(defcustom coq-optimise-resp-windows-enable t
  "If non-nil (default) resize vertically response windw after each command."
  :type 'boolean
  :group 'coq)

;; Default coq is only Private_ and _subproof
(defcustom coq-search-blacklist-string ; add this? \"_ind\" \"_rect\" \"_rec\" 
 "\"Private_\" \"_subproof\""
  "String for blacklisting strings from requests to coq environment."
  :type 'string
  :group 'coq)

(defcustom coq-prefer-top-of-conclusion nil
  "prefer start of the conclusion over its end when displaying goals
that do not fit in the goals window."
  :type 'boolean
  :group 'coq)

;; this remembers the previous value of coq-search-blacklist-string, so that we
;; can cook a remove+add blacklist command each time the variable is changed.
;; initially we put it at current value of coq-search-blacklist-string.
(defvar coq-search-blacklist-string-prev coq-search-blacklist-string)

;TODO: remove Set Undo xx. It is obsolete since coq-8.5 at least.
;;`(,(format "Set Undo %s . " coq-default-undo-limit) "Set Printing Width 75.")
(defconst coq-shell-init-cmd
  (append `(,(format "Add Search Blacklist %s. " coq-search-blacklist-string)) coq-user-init-cmd)
 "Command to initialize the Coq Proof Assistant.")


(require 'coq-syntax)
;; FIXME: Even if we don't use coq-indent for indentation, we still need it for
;; coq-script-parse-cmdend-forward/backward and coq-find-real-start.
(require 'coq-indent)


;; Command to reset the Coq Proof Assistant
(defconst coq-shell-restart-cmd "Reset Initial.\n ")

(defvar coq-shell-prompt-pattern
  "\\(?:\n\\(?:[^\n\371]+\371\\|<prompt>[^\n]+</prompt>\\)\\)"
  "*The prompt pattern for the inferior shell running coq.")

;; FIXME da: this was disabled (set to nil) -- why?
;; da: 3.5: add experimental
;; am:answer: because of bad interaction
;; with coq -R option.
(defvar coq-shell-cd nil
;;  "Add LoadPath \"%s\"." ;; fixes unadorned Require (if .vo exists).
  "*Command of the inferior process to change the directory.")

(defvar coq-shell-proof-completed-regexp "No\\s-+more\\s-+subgoals\\.\\|Subtree\\s-proved!\\|Proof\\s-completed"; \\|This subproof is complete
  "*Regular expression indicating that the proof has been completed.")

(defvar coq-goal-regexp
  "\\(============================\\)\\|\\(subgoal [0-9]+\\)\n")


(defconst coq-interrupt-regexp "User Interrupt."
  "Regexp corresponding to an interrupt.")

(defcustom coq-end-goals-regexp-show-subgoals "\n(dependent evars:"
  "Regexp for `proof-shell-end-goals-regexp' when showing all subgoals.
A setting of nil means show all output from Coq. See also
`coq-hide-additional-subgoals'."
  :type '(choice regexp (const nil))
  :group 'coq)

(defcustom coq-end-goals-regexp-hide-subgoals
  (concat "\\(\nsubgoal 2 \\)\\|\\(" coq-end-goals-regexp-show-subgoals "\\)")
  "Regexp for `proof-shell-end-goals-regexp' when hiding additional subgoals.
See also `coq-hide-additional-subgoals'."
  :type '(choice regexp (const nil))
  :group 'coq)

;;
;; prooftree customization
;;

(defgroup coq-proof-tree ()
  "Coq specific customization for prooftree."
  :group 'coq-config
  :package-version '(ProofGeneral . "4.2"))

;; Ignore all commands that start a proof. Otherwise "Proof" will appear
;; as superfluous node in the proof tree. Note that we cannot ignore Proof,
;; because, Fixpoint does not display the proof goal, see Coq bug #2776. 
(defcustom coq-proof-tree-ignored-commands-regexp
  (concat "^\\(\\(Show\\)\\|\\(Locate\\)\\|"
          "\\(Theorem\\)\\|\\(Lemma\\)\\|\\(Remark\\)\\|\\(Fact\\)\\|"
          "\\(Corollary\\)\\|\\(Proposition\\)\\|\\(Definition\\)\\|"
          "\\(Let\\)\\|\\(Fixpoint\\)\\|\\(CoFixpoint\\)\\)")
  "Regexp for `proof-tree-ignored-commands-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-navigation-command-regexp
  (concat "^\\(\\(Focus\\)\\|\\(Unfocus\\)\\|"
          "\\(all\\s-*:\\s-*\\(cycle\\|swap\\|revgoals\\)\\)\\|"
          "\\(\\+\\)\\|\\(-\\)\\|\\(\\*\\)\\|\\({\\)\\|\\(}\\)\\)")
  "Regexp for `proof-tree-navigation-command-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-cheating-regexp
  "\\(?:admit\\)\\|\\(?:give_up\\)"
  "Regexp for `proof-tree-cheating-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-new-layer-command-regexp
  "^\\(\\(Proof\\)\\|\\(Grab Existential Variables\\)\\)"
  "Regexp for `proof-tree-new-layer-command-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-current-goal-regexp
  (concat "^[0-9]+ \\(?:focused \\)?subgoal\\(?:s\\)?\\s-*"
          "\\(?:(\\(?:unfocused: [-0-9]+\\)?,?"
          "\\s-*\\(?:shelved: [-0-9]+\\)?)\\)?\\(?:\\s-*, subgoal 1\\)? "
          "(ID \\([0-9]+\\))\n\\s-*\n\\(\\(?: .*\n\\)+\\)\\(?:\n\\|$\\)")
  "Regexp for `proof-tree-current-goal-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-update-goal-regexp
  (concat "^goal / evar \\([0-9]+\\) is:\n"
          "\\s-*\n\\(\\(?:.+\n\\)*\\)\\(?:\n\\|$\\)")
  "Regexp for `proof-tree-update-goal-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-additional-subgoal-ID-regexp
  "^subgoal [0-9]+ (ID \\([0-9]+\\)) is:"
  "Regexp for `proof-tree-additional-subgoal-ID-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-existential-regexp "\\(\\?[0-9]+\\)"
  "Regexp for `proof-tree-existential-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-instantiated-existential-regexp
  (concat coq-proof-tree-existential-regexp " using")
  "Regexp for recognizing an instantiated existential variable."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-existentials-state-start-regexp
  "^(dependent evars:"
  "Coq instance of `proof-tree-existentials-state-start-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

(defcustom coq-proof-tree-existentials-state-end-regexp ")\n"
  "Coq instance of `proof-tree-existentials-state-end-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)

;; 8.4:
;; <infomsg>This subproof is complete, but there are still unfocused goals.</infomsg>
;;
;; 8.5:
;; <infomsg>
;; This subproof is complete, but there are some unfocused goals.
;; Focus next goal with bullet *.
;; </infomsg>
;;
;; <infomsg>No more subgoals, but there are some goals you gave up:</infomsg>
;;
;; <infomsg>All the remaining goals are on the shelf.</infomsg>
(defcustom coq-proof-tree-branch-finished-regexp
  (concat "^\\(\\(?:Proof completed\\.\\)\\|"
          "\\(?:\\(?:<infomsg>\\)?No more subgoals\\)\\|"
          "\\(No more subgoals but non-instantiated "
          "existential variables:\\)\\|"
          "\\(?:<infomsg>All the remaining goals are on the shelf\\)\\|"
          "\\(<infomsg>\\s-*This subproof is complete, but there are "
          "\\(?:still\\|some\\) unfocused goals.\\)\\)")
  "Regexp for `proof-tree-branch-finished-regexp'."
  :type 'regexp
  :group 'coq-proof-tree)


;;
;; Outline mode
;;

;; FIXME, deal with interacive "Definition"
(defvar coq-outline-regexp
;;  (concat "(\\*\\|"
  (concat "[ ]*" (regexp-opt
                  '(
                    "Ltac" "Corr" "Modu" "Sect" "Chap" "Goal"
                    "Definition" "Lemm" "Theo" "Fact" "Rema"
                    "Mutu" "Fixp" "Func") t)))
;;)

(defvar coq-outline-heading-end-regexp "\\.[ \t\n]")

(defvar coq-shell-outline-regexp coq-goal-regexp)
(defvar coq-shell-outline-heading-end-regexp coq-goal-regexp)


(defconst coq-state-preserving-tactics-regexp
  (proof-regexp-alt-list coq-state-preserving-tactics))
(defconst coq-state-changing-commands-regexp
  (proof-regexp-alt-list coq-keywords-state-changing-commands))
(defconst coq-state-preserving-commands-regexp
  (proof-regexp-alt-list coq-keywords-state-preserving-commands))
(defconst coq-commands-regexp
  (proof-regexp-alt-list coq-keywords-commands))
(defvar coq-retractable-instruct-regexp
  (proof-regexp-alt-list coq-retractable-instruct))
(defvar coq-non-retractable-instruct-regexp
  (proof-regexp-alt-list coq-non-retractable-instruct))


;;
;; Derived modes
;;

(eval-and-compile ;; FIXME: Why?
  (define-derived-mode coq-shell-mode proof-shell-mode
    "Coq Shell" nil
    (coq-shell-mode-config)))

(eval-and-compile ;; FIXME: Why?
  (define-derived-mode coq-response-mode proof-response-mode
  "Coq Response" nil
    (coq-response-config)))

(eval-and-compile ;; FIXME: Why?
  (define-derived-mode coq-mode proof-mode "Coq"
    "Major mode for Coq scripts.

\\{coq-mode-map}"
    (coq-mode-config)))

(eval-and-compile ;; FIXME: Why?
  (define-derived-mode coq-goals-mode proof-goals-mode
    "Coq Goals" nil
    (coq-goals-mode-config)))

;; Indentation and navigation support via SMIE.

(defcustom coq-use-smie t
  "OBSOLETE. smie code is always used now.

If non-nil, Coq mode will try to use SMIE for indentation.
SMIE is a navigation and indentation framework available in Emacs >= 23.3."
  :type 'boolean
  :group 'coq)

(require 'smie nil 'noerror)
(require 'coq-smie nil 'noerror)


;;
;; Auxiliary code for Coq modes
;;

;; finding the main frame of pg.
(defun coq-find-threeb-frames ()
  "Return a list of frames displaying both response and goals buffers."
  (let* ((wins-resp (get-buffer-window-list proof-response-buffer nil t))
         (wins-gls (get-buffer-window-list proof-goals-buffer nil t))
         (frame-resp (cl-mapcar 'window-frame wins-resp))
         (frame-gls (cl-mapcar 'window-frame wins-gls)))
    (filtered-frame-list (lambda (x) (and (member x frame-resp) (member x frame-gls))))))


(defun coq-remove-trailing-blanks (s)
  (let ((pos (string-match "\\s-*\\'" s)))
    (substring s 0 pos)))

(defun coq-remove-starting-blanks (s)
  (string-match "\\`\\s-*" s)
  (substring s (match-end 0) (length s)))


;; Messages dispalyed by "Time" are always following or preceding the real
;; result, if it follows we want it to be non urgent, otherwise the result
;; would not be shown in response buffer. If it is before, then we want it
;; urgent so that it is displayed.
(defvar coq-eager-no-urgent-regex "\\s-*Finished "
  "Regexp of commands matching proof-shell-eager-annotation-start
  that should maybe not be classified as urgent messages.")

;; return the end position if found, nil otherwise
(defun coq-non-urgent-eager-annotation ()
  (save-excursion
    (when (and (looking-at coq-eager-no-urgent-regex)
               (re-search-forward proof-shell-eager-annotation-end nil t))
      (let ((res (match-end 0))); robustify
        ;; if there is something else than a prompt here then this eager
        ;; annotation is left urgent (return nil), otherwise it is not urgent
        ;; (return position of the end of the annotation)
        (when (looking-at (concat "\\s-*" proof-shell-annotated-prompt-regexp))
          res)))))

;; Looking for eager annotation which does not match coq-eager-no-urgent-regex
(defun coq-search-urgent-message ()
  "Find forward the next really urgent message.
Return the position of the beginning of the message (after the
annotation-start) if found."
  (let ((again t) (found nil) (start-start nil) (end-end nil)
        (eager proof-shell-eager-annotation-start))
    (while again
      (setq start-start (and (re-search-forward eager nil 'limit)
                             (match-beginning 0)))
      (setq end-end (and start-start (coq-non-urgent-eager-annotation)))
      (unless end-end
        (setq again nil) ; exit while
        ;; display message (this prints the message once now but it will be
        ;; reprinted as a normal output, bad?)
        ;;(proof-shell-process-urgent-message start-start end-end)
        ))
    (and start-start (goto-char start-start))))

;; This is a modified version of the same function in generic/proof-shell.el.
;; Using function coq-search-urgent-message instead of regex
;; proof-shell-eager-annotation-start, in order to let non urgent message as
;; such. i.e. "Time" messages. 
(defun proof-shell-process-urgent-messages ()
  "Scan the shell buffer for urgent messages.
Scanning starts from `proof-shell-urgent-message-scanner' or
`scomint-last-input-end', which ever is later.  We deal with strings
between regexps `proof-shell-eager-annotation-start' and
`proof-shell-eager-annotation-end'.

We update `proof-shell-urgent-message-marker' to point to last message found.

This is a subroutine of `proof-shell-filter'."
  (let ((pt (point)) (end t)
	lastend laststart
	(initstart (max  (marker-position proof-shell-urgent-message-scanner)
			 (marker-position scomint-last-input-end))))
    (goto-char initstart)
    (while (and end (setq laststart (coq-search-urgent-message))
                )
;      (setq laststart (match-beginning 0))
      (if (setq end
		(re-search-forward proof-shell-eager-annotation-end nil t))
	  (save-excursion
	    (setq lastend end)
	    ;; Process the region including the annotations
	    (proof-shell-process-urgent-message laststart lastend))))

    (set-marker
     proof-shell-urgent-message-scanner
     (if end ;; couldn't find message start; move forward to avoid rescanning
	 (max initstart
	      (- (point)
		 (1+ proof-shell-eager-annotation-start-length)))
       ;; incomplete message; leave marker at start of message
       laststart))

    ;; Set position of last urgent message found
    (if lastend
	(set-marker proof-shell-urgent-message-marker lastend))
	
    (goto-char pt)))

;; Due to the architecture of proofgeneral, informative message put *before*
;; the goal disappear unless marked as "urgent", i.e. being enclosed with
;; "eager-annotation" syntax. Since we don't want the Warning color to be used
;; for simple informative message, we have to redefine this function to use
;; normal face when the "eager annotation" is acutally not a warning. This is a
;; modified version of the same function in generic/proof-shell.el.
(defun proof-shell-process-urgent-message-default (start end)
  "A subroutine of `proof-shell-process-urgent-message'."
  ;; Clear the response buffer this time, but not next, leave window.
  (pg-response-maybe-erase nil nil)
  (proof-minibuffer-message
   (buffer-substring-no-properties
    (save-excursion
      (re-search-forward proof-shell-eager-annotation-start end nil)
      (point))
    (min end
         (save-excursion (end-of-line) (point))
         (+ start 75))))
  (let*
      ((face
        (progn (goto-char start)
               (if (looking-at "<infomsg>") 'default
                 'proof-eager-annotation-face)))
       (str (proof-shell-strip-eager-annotations start end))
       (strnotrailingspace
        (coq-remove-starting-blanks (coq-remove-trailing-blanks str))))
    (pg-response-display-with-face strnotrailingspace))) ; face


;;;;;;;;;;; Trying to accept { and } as terminator for empty commands. Actually
;;;;;;;;;;; I am experimenting two new commands "{" and "}" (without no
;;;;;;;;;;; trailing ".") which behave like BeginSubProof and EndSubproof. The
;;;;;;;;;;; absence of a trailing "." makes it difficult to distinguish between
;;;;;;;;;;; "{" of normal coq code (implicits, records) and this the new
;;;;;;;;;;; commands. We therefore define a coq-script-parse-function to this
;;;;;;;;;;; purpose.

;; coq-end-command-regexp is ni coq-indent.el
(defconst coq-script-command-end-regexp coq-end-command-regexp)
;;        "\\(?:[^.]\\|\\(?:\\.\\.\\)\\)\\.\\(\\s-\\|\\'\\)")



;; slight modification of proof-script-generic-parse-cmdend (one of the
;; candidate for proof-script-parse-function), to allow "{" and "}" to be
;; command terminator when the command is empty. TO PLUG: swith the comment
;; below and rename coq-script-parse-function2 into coq-script-parse-function
(defun coq-script-parse-function ()
  "For `proof-script-parse-function' if `proof-script-command-end-regexp' set."
  (coq-script-parse-cmdend-forward))

;;;;;;;;;;;;;;;;;;;;;;;;;; End of "{" and "} experiments ;;;;;;;;;;;;


;;;;;;;;;;;;;;;;;;;;;;;;;; Freeze buffers ;;;;;;;;;;;;
;; For storing output of respnse and goals buffers into a permanent buffer.

(defun coq-clone-buffer-response-mode (s &optional erase)
  (let ((already-existing (get-buffer s))
        (nb (get-buffer-create s)))
    (save-window-excursion
      (switch-to-buffer nb)
      (unless already-existing
        (coq-response-mode)
        (read-only-mode 0))
      (goto-char (point-min))
      (insert "\n************************************\n")
      (goto-char (point-min)))
    (if erase (copy-to-buffer nb (point-min) (point-max))
      (append-to-buffer nb (point-min) (point-max)))
    ;; (set-window-point window pos)
    nb))

;; copy the content of proof-response-buffer into the "response-freeze" buffer,
;; resetting its content if ERASE non nil.
(defun proof-store-buffer-win (buffer &optional erase)
  (proof-with-current-buffer-if-exists buffer
    (let ((newbuffer nil))
      (set-buffer buffer)
      (setq newbuffer (coq-clone-buffer-response-mode "*response-freeze*" erase))
      (let ((win (display-buffer-other-frame newbuffer))
            (win-point-min (save-window-excursion
                             (switch-to-buffer-other-frame newbuffer)
                             (point-min))))
      (set-window-point win win-point-min)))))

(defun proof-store-response-win (&optional erase)
  (interactive "P")
  (proof-store-buffer-win proof-response-buffer erase))

(defun proof-store-goals-win (&optional erase)
  (interactive "P")
  (proof-store-buffer-win proof-goals-buffer erase))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;



;; make this non recursive?
(defun build-list-id-from-string (s)
  "Build a list of string from a string S of the form \"id1|id2|...|idn\"."
  (if (or (not s) (string= s "")) '()
    (let ((x (string-match (concat "\\(" coq-id-shy "\\)\\(?:|\\|\\'\\)\\(.*\\)") s)))
      (if (not x) (error "Cannot extract list of ids from string")
        (cons (match-string 1 s)
              (build-list-id-from-string (match-string 2 s)))))))

;; Use the statenumber inside the coq prompt to backtrack more easily
(defun coq-last-prompt-info (s)
  "Extract info from the coq prompt S.  See `coq-last-prompt-info-safe'."
  (let ((lastprompt (or s (error "No prompt !!?")))
        (regex
         (concat ">\\(" coq-id-shy "\\) < \\([0-9]+\\) |\\(\\(?:" coq-id-shy
                 "|?\\)*\\)| \\([0-9]+\\) < ")))
    (when (string-match regex lastprompt)
      (let ((current-proof-name (match-string 1 lastprompt))
            (state-number (string-to-number (match-string 2 lastprompt)))
            (proof-state-number (string-to-number (match-string 4 lastprompt)))
            ;; bind pending-proofs last, because build-list-id-from-string
            ;; modifies the match data
            (pending-proofs
             (build-list-id-from-string (match-string 3 lastprompt))))
        (list state-number proof-state-number pending-proofs
              (if pending-proofs current-proof-name nil))))))


(defun coq-last-prompt-info-safe ()
  "Return a list with all informations from the last prompt.
The list contains in the following order the state number, the
proof stack depth, a list with the names of all pending proofs,
and as last element the name of the current proof (or nil if
there is none)."
  (coq-last-prompt-info proof-shell-last-prompt))

(defvar coq-last-but-one-statenum 1
  "The state number we want to put in a span.
This is the prompt number given *just before* the command was sent.
This variable remembers this number and will be updated when
used see coq-set-state-number.
Initially 1 because Coq initial state has number 1.")

(defvar coq-last-but-one-proofnum 1
  "As for `coq-last-but-one-statenum' but for stack depth.")

(defvar coq-last-but-one-proofstack '()
  "As for `coq-last-but-one-statenum' but for proof stack symbols.")

(defsubst coq-get-span-statenum (span)
  "Return the state number of the SPAN."
  (span-property span 'statenum))

(defsubst coq-get-span-proofnum (span)
  "Return the proof number of the SPAN."
  (span-property span 'proofnum))

(defsubst coq-get-span-proofstack (span)
  "Return the proof stack (names of pending proofs) of the SPAN."
  (span-property span 'proofstack))

(defsubst coq-set-span-statenum (span val)
  "Set the state number of the SPAN to VAL."
  (span-set-property span 'statenum val))

(defsubst coq-get-span-goalcmd (span)
  "Return the 'goalcmd flag of the SPAN."
  (span-property span 'goalcmd))

(defsubst coq-set-span-goalcmd (span val)
  "Set the 'goalcmd flag of the SPAN to VAL."
  (span-set-property span 'goalcmd val))

(defsubst coq-set-span-proofnum (span val)
  "Set the proof number of the SPAN to VAL."
  (span-set-property span 'proofnum val))

(defsubst coq-set-span-proofstack (span val)
  "Set the proof stack (names of pending proofs) of the SPAN to VAL."
  (span-set-property span 'proofstack val))

(defsubst proof-last-locked-span ()
  (with-current-buffer proof-script-buffer
    (span-at (- (proof-unprocessed-begin) 1) 'type)))

;; Each time the state changes (hook below), (try to) put the state number in
;; the last locked span (will fail if there is already a number which should
;; happen when going back in the script).  The state number we put is not the
;; last one because the last one has been sent by Coq *after* the change. We
;; use `coq-last-but-one-statenum' instead and then update it.

;;TODO update docstring and comment

(defun coq-set-state-infos ()
  "Set the last locked span's state number to the number found last time.
This number is in the *last but one* prompt (variable `coq-last-but-one-statenum').
If locked span already has a state number, then do nothing. Also updates
`coq-last-but-one-statenum' to the last state number for next time."
  (if proof-shell-last-prompt
      ;; da: did test proof-script-buffer here, but that seems wrong
      ;; since restart needs to reset these values.
      ;; infos = promt infos of the very last prompt
      ;; sp = last locked span, which we want to fill with prompt infos
      (let ((sp    (if proof-script-buffer (proof-last-locked-span)))
            (infos (or (coq-last-prompt-info-safe)
                       ;; the line above seems to return nil sometimes, let us
                       ;; issue a warning when this happens, so that we
                       ;; understand why.
                       (and (display-warning
                             'proof-general
                             "oops nothing returned by (coq-last-prompt-info-safe)!!!" :debug) nil)
                       '(0 0 nil nil))))
        (unless (or (not sp) (coq-get-span-statenum sp))
          (coq-set-span-statenum sp coq-last-but-one-statenum))
        (setq coq-last-but-one-statenum (car infos))
        ;; set goalcmd property if this is a goal start
        ;; (ie proofstack has changed and not a save cmd)
        (unless
            (or (not sp) (equal (span-property sp 'type) 'goalsave)
                (<= (length (car (cdr (cdr infos))))
                    (length coq-last-but-one-proofstack)))
          (coq-set-span-goalcmd sp t))
        ;; testing proofstack=nil is not good here because nil is the empty list OR
        ;; the no value, so we test proofnum as it is always set at the same time.
        ;; This is why this test is done before the next one (which sets proofnum)
        (unless (or (not sp) (coq-get-span-proofnum sp))
          (coq-set-span-proofstack sp coq-last-but-one-proofstack))
        (setq coq-last-but-one-proofstack (car (cdr (cdr infos))))
        (unless (or (not sp) (coq-get-span-proofnum sp))
          (coq-set-span-proofnum sp coq-last-but-one-proofnum))
        (setq coq-last-but-one-proofnum (car (cdr infos))))))

;; This hook seems the one we want.
;; WARNING! It is applied once after each command PLUS once before a group of
;; commands is started
(add-hook 'proof-state-change-hook 'coq-set-state-infos)


(defun count-not-intersection (l notin)
  "Return the number of elts of L that are not in NOTIN."
  (let ((l1 l) (l2 notin) (res 0))
    (while l1
      (if (member (car l1) l2) ()
        (setq res (+ res 1))) ; else
      (setq l1 (cdr l1)))
    res
    ))

;; Simplified version of backtracking which uses state numbers, proof stack depth and
;; pending proofs put inside the coq (> v8.1) prompt. It uses the new coq command
;; "Backtrack". The prompt is like this:
;;      state                        proof stack
;;      num                           depth
;;       __                              _
;; aux < 12 |aux|SmallStepAntiReflexive| 4 < \371
;; ^^^^^^   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^     ^
;; usual           pending proofs           usual
;;                                          special char
;; exemple:
;; to go (back) from 12 |lema1|lema2...|leman| xx
;; to                8  |lemb1|lemb2...|lembm| 5
;; we must do "Backtrack 8 5 naborts"
;; where naborts is the number of lemais that are not lembis

;; Rem: We could deal with suspend and resume with more work. We would need a new coq
;; command, because it is better to backtrack with *one* command (because
;; proof-change-hook used above is not exactly called at right times).

(defun coq-find-and-forget (span)
  "Backtrack to SPAN.  Using the \"Backtrack n m p\" coq command."
  (if (eq (span-property span 'type) 'proverproc)
      ;; processed externally (i.e. Require, etc), nothing to do
      ;; (should really be unlocked when we undo the Require).
      nil
  (let* (ans (naborts 0) (nundos 0)
             (proofdepth (coq-get-span-proofnum span))
             (proofstack (coq-get-span-proofstack span))
             (span-staten (coq-get-span-statenum span))
             (naborts (count-not-intersection
                       coq-last-but-one-proofstack proofstack)))
    ;; if we move outside of any proof, coq does not print anything, so clean
    ;; the goals buffer otherwise the old one will still be displayed
    (if (= proofdepth 0) (proof-clean-buffer proof-goals-buffer))
    (unless (and
             ;; return nil (was proof-no-command) in this case:
             ;; this is more efficient as backtrack x y z may be slow
             (equal coq-last-but-one-proofstack proofstack)
             (= coq-last-but-one-proofnum proofdepth)
             (= coq-last-but-one-statenum span-staten))
      (list
       (format "Backtrack %s %s %s . "
               (int-to-string span-staten)
               (int-to-string proofdepth)
               naborts))))))

(defvar coq-current-goal 1
  "Last goal that Emacs looked at.")

(defun coq-goal-hyp ()
  (cond
   ((looking-at "============================\n")
    (goto-char (match-end 0))
    (cons 'goal (int-to-string coq-current-goal)))
   ((looking-at "subgoal \\([0-9]+\\) is:\n")
    (goto-char (match-end 0))
    (cons 'goal (match-string 1))       ;FIXME: This is dead-code!?  --Stef
    (setq coq-current-goal (string-to-number (match-string 1))))
   ((proof-looking-at proof-shell-assumption-regexp)
    (cons 'hyp (match-string 1)))
   (t nil)))

(defun coq-state-preserving-p (cmd)
  ;; (or
   (proof-string-match coq-non-retractable-instruct-regexp cmd))
  ;; (and
  ;;  (not (proof-string-match coq-retractable-instruct-regexp cmd))
  ;;  (or
  ;;   (message "Unknown command, hopes this won't desynchronize ProofGeneral")
  ;;   t))))


(defun coq-hide-additional-subgoals-switch ()
  "Function invoked when the user switches `coq-hide-additional-subgoals'."
  (if coq-time-commands
      (progn
        (setq coq-hide-additional-subgoals nil)
        (error
         "You must disable ``Time Commands'' (var coq-time-commands) first"))
    (if coq-hide-additional-subgoals
        (setq proof-shell-end-goals-regexp coq-end-goals-regexp-hide-subgoals)
      (setq proof-shell-end-goals-regexp coq-end-goals-regexp-show-subgoals))))

(defun coq-time-commands-switch ()
  "Function invoked when the user switches `coq-time-commands'.
Resets `coq-hide-additional-subgoals' and puts nil into
`proof-shell-end-goals-regexp' to ensure the timing is visible in
the *goals* buffer."
  (if coq-time-commands
      (progn
        (let ((coq-time-commands nil))
          (customize-set-variable 'coq-hide-additional-subgoals nil))
        (setq proof-shell-end-goals-regexp nil))
    (coq-hide-additional-subgoals-switch)))

;;
;; Commands for Coq
;;

(defconst notation-print-kinds-table
  '(("Print Scope(s)" 0) ("Print Visibility" 1))
  "Enumerates the different kinds of notation information one can ask to coq.")

(defun coq-PrintScope ()
  "Show information on notations. Coq specific."
  (interactive)
  (let*
      ((mods
        (completing-read "Infos on notation (TAB to see list): "
                         notation-print-kinds-table))
       (s (read-string  "Name (empty for all): "))
       (all (string-equal s "")))
    (cond
     ((and (string-equal mods "Print Scope(s)") (string-equal s ""))
      (proof-shell-invisible-command (format "Print Scopes.")))
     (t
      (proof-shell-invisible-command (format "%s %s ." mods s)))
     )
    )
  )

(defun coq-remove-trailing-dot (s)
  "Return the string S without its trailing \".\" if any.
Return nil if S is nil."
  (if (and s (string-match "\\.\\'" s))
      (substring s 0 (- (length s) 1))
    s))

(defun coq-remove-heading-quote (s)
  "Return the string S without its heading \"\'\" if any.
Return nil if S is nil."
  (if (and s (string-match "\\`'" s))
      (substring s 1 (length s))
    s))

(defun coq-clean-id-at-point (s)
  (coq-remove-heading-quote (coq-remove-trailing-dot s)))

(defun coq-is-symbol-or-punct (c)
  "Return non nil if character C is a punctuation or a symbol constituent.
If C is nil, return nil."
  (when c
    (or (equal (char-syntax c) ?\.) (equal (char-syntax c) ?\_))))

(defun coq-grab-punctuation-left (pos)
  "Return a string made of punctuations chars found immediately before position POS."
  (let ((res nil)
        (currpos pos))
    (while (coq-is-symbol-or-punct (char-before currpos))
      (setq res (concat (char-to-string (char-before currpos)) res))
      (setq currpos (- currpos 1)))
    res))


(defun coq-grab-punctuation-right (pos)
  "Return a string made of punctuations chars found immediately after position POS."
  (let ((res nil)
        (currpos pos))
    (while (coq-is-symbol-or-punct (char-after currpos))
      (setq res (concat res (char-to-string (char-after currpos))))
      (setq currpos (+ currpos 1)))
    res))

(defun coq-notation-at-position (pos)
  "Return the notation at current point.
Support dot.notation.of.modules."
  (coq-with-altered-syntax-table
   (when (or (coq-grab-punctuation-left pos) (coq-grab-punctuation-right pos))
     (concat (coq-grab-punctuation-left pos)
             (coq-grab-punctuation-right pos)))))

(defun coq-string-starts-with-symbol (s)
  (eq 0 (string-match "\\s_" s)))

;; remove trailing dot if any.
(defun coq-id-at-point ()
  "Return the identifier at current point.
Support dot.notation.of.modules."
  (coq-with-altered-syntax-table
   (let* ((symb (cond
                 ((fboundp 'symbol-near-point) (symbol-near-point))
                 ((fboundp 'symbol-at-point) (symbol-at-point))))
          (symbclean (when symb (coq-clean-id-at-point (symbol-name symb)))))
     (when (and symb (not (zerop (length symbclean))))
       symbclean))))


(defun coq-id-or-notation-at-point ()
  (or (coq-id-at-point)
      (let ((notation (coq-notation-at-position (point))))
        (if notation (concat "\"" notation "\"") ""))))

(defcustom coq-remap-mouse-1 nil
  "Wether coq mode should remap mouse button 1 to coq queries.

This overrides the default global binding of (control mouse-1) and
(shift mouse-1) (buffers and faces menus). Hence it is nil by
default."
  :type 'boolean
  :group 'coq)


;; On a mouse event, try to query the id at point clicked.
(defun coq-id-under-mouse-query (event)
  "Query the prover about the identifier or notation near mouse click EVENT.
This is mapped to control/shift mouse-1, unless coq-remap-mouse-1
is nil (t by default)."
  (interactive "e")
  (save-selected-window
    (save-selected-frame
     (save-excursion
       (mouse-set-point event)
       (let* ((id (coq-id-at-point))
              (notat (coq-notation-at-position (point)))
              (modifs (event-modifiers event))
              (shft (member 'shift modifs))
              (ctrl (member 'control modifs))
              (cmd (when (or id notat)
                     (if (and ctrl shft) (if id "Check" "Locate")
                       (if shft (if id "About" "Locate")
                         (if ctrl (if id "Print" "Locate")))))))
         (proof-shell-invisible-command
          (format (concat  cmd " %s . ")
                  ;; Notation need to be surrounded by ""
                  (if id id (concat "\"" notat "\"")))))))))

(defun coq-guess-or-ask-for-string (s &optional dontguess)
  "Asks for a coq identifier with message S.
If DONTGUESS is non nil, propose a default value as follows:

If region is active, propose its containt as default value.

Otherwise propose identifier at point if any."
  (let* ((guess
          (cond
           (dontguess nil)
           ((use-region-p)
            (buffer-substring-no-properties (region-beginning) (region-end)))
           (t (coq-id-or-notation-at-point)))))
    (read-string
     (if guess (concat s " (default " guess "): ") (concat s ": "))
     nil 'proof-minibuffer-history guess)))


(defun coq-ask-do (ask do &optional dontguess postformatcmd)
  "Ask for an ident and print the corresponding term."
  (let* ((cmd) (postform (if (eq postformatcmd nil) 'identity postformatcmd)))
    (proof-shell-ready-prover)
    (setq cmd (coq-guess-or-ask-for-string ask dontguess))
    (proof-shell-invisible-command
     (format (concat do " %s . ") (funcall postform cmd)))))


(defun coq-flag-is-on-p (testcmd)
  (proof-shell-ready-prover)
  (proof-shell-invisible-command (format testcmd) 'wait)
  (let ((resp proof-shell-last-response-output))
    (string-match "is on\\>" resp)))

(defun coq-command-with-set-unset (setcmd cmd unsetcmd &optional postformatcmd testcmd)
  "Play commands SETCMD then CMD and then silently UNSETCMD."
  (let* ((postform (if (eq postformatcmd nil) 'identity postformatcmd))
         (flag-is-on (and testcmd (coq-flag-is-on-p testcmd))))
    (unless flag-is-on (proof-shell-invisible-command
                        (format " %s . " (funcall postform setcmd)) 'wait))
    (proof-shell-invisible-command
     (format " %s . " (funcall postform cmd)) 'wait)
    (unless flag-is-on (proof-shell-invisible-command-invisible-result
                        (format " %s . " (funcall postform unsetcmd))))))

(defun coq-ask-do-set-unset (ask do setcmd unsetcmd
                                 &optional dontguess postformatcmd tescmd)
  "Ask for an ident id and execute command DO in SETCMD mode.
More precisely it executes SETCMD, then DO id and finally silently UNSETCMD."
  (let* ((cmd) (postform (if (eq postformatcmd nil) 'identity postformatcmd tescmd)))
    (proof-shell-ready-prover)
    (setq cmd (coq-guess-or-ask-for-string ask dontguess))
    (coq-command-with-set-unset setcmd (concat do " " cmd) unsetcmd postformatcmd)))


(defun coq-ask-do-show-implicits (ask do &optional dontguess postformatcmd)
  "Ask for an ident and print the corresponding term."
  (coq-ask-do-set-unset ask do
                        "Set Printing Implicit"
                        "Unset Printing Implicit"
                        dontguess postformatcmd
                        "Test Printing Implicit"))

(defun coq-ask-do-show-all (ask do &optional dontguess postformatcmd)
  "Ask for an ident and print the corresponding term."
  (coq-ask-do-set-unset ask do
                        "Set Printing All"
                        "Unset Printing All"
                        dontguess postformatcmd
                        "Test Printing All"))


  ;; (let* ((cmd) (postform (if (eq postformatcmd nil) 'identity postformatcmd)))
    

  ;;   (proof-shell-ready-prover)
  ;;   (setq cmd (coq-guess-or-ask-for-string ask dontguess))
  ;;   (coq-command-with-set-unset
  ;;    "Set Printing Implicit"
  ;;    (format (concat do " %s . ") cmd)
  ;;    "Unset Printing Implicit" )
  ;;   ))


(defsubst coq-put-into-brackets (s)
  (concat "[ " s " ]"))

(defsubst coq-put-into-double-quote-if-notation (s)
  (if (coq-is-symbol-or-punct (string-to-char s))
      (concat "\"" s "\"")
    s))


(defun coq-build-removed-pattern (s)
  (concat " -\"" s "\""))

(defun coq-build-removed-patterns (l)
  (mapcar 'coq-build-removed-pattern l))

(defsubst coq-put-into-quotes (s)
  (concat "\"" s "\""))

(defun coq-SearchIsos ()
  "Search a term whose type is isomorphic to given type.
This is specific to `coq-mode'."
  (interactive)
  (coq-ask-do
   "SearchPattern (parenthesis mandatory), ex: (?X1 + _ = _ + ?X1)"
   "SearchPattern" nil))

(defun coq-SearchConstant ()
  (interactive)
  (coq-ask-do "Search constant" "Search"))

(defun coq-SearchRewrite ()
  (interactive)
  (coq-ask-do "SearchRewrite" "SearchRewrite" nil))

;; TODO SearchAbout become Search in v8.5, change when V8.4 becomes old.
(defun coq-SearchAbout ()
  (interactive)
  (coq-ask-do
   ;; TODO: use [Add Search Blacklist "foo"] to exclude optionaly some patterns:
   ;;  "_ind" "_rec" "R_" "_equation"
   "SearchAbout (ex: \"eq_\" eq -bool)"
   "SearchAbout")
  (message "use [Coq/Settings/Search Blacklist] to change blacklisting."))



(defun coq-Print (withprintingall)
  "Ask for an ident and print the corresponding term.
With flag Printing All if some prefix arg is given (C-u)."
  (interactive "P")
  (if withprintingall
      (coq-ask-do-show-all "Print" "Print")
    (coq-ask-do "Print" "Print")))

(defun coq-Print-with-implicits ()
  "Ask for an ident and print the corresponding term."
  (interactive)
  (coq-ask-do-show-implicits "Print" "Print"))

(defun coq-Print-with-all ()
  "Ask for an ident and print the corresponding term."
  (interactive)
  (coq-ask-do-show-all "Print" "Print"))

(defun coq-About (withprintingall)
  "Ask for an ident and print information on it."
  (interactive "P")
  (if withprintingall
      (coq-ask-do-show-all "About" "About")
    (coq-ask-do "About" "About")))

(defun coq-About-with-implicits ()
  "Ask for an ident and print information on it."
  (interactive)
  (coq-ask-do-show-implicits "About" "About"))

(defun coq-About-with-all ()
  "Ask for an ident and print information on it."
  (interactive)
  (coq-ask-do-show-all "About" "About"))


(defun coq-LocateConstant ()
  "Locate a constant."
  (interactive)
  (coq-ask-do "Locate" "Locate"))

(defun coq-LocateLibrary ()
  "Locate a library."
  (interactive)
  (coq-ask-do "Locate Library" "Locate Library"))

(defun coq-LocateNotation ()
  "Locate a notation.  Put it automatically into quotes.
This is specific to `coq-mode'."
  (interactive)
  (coq-ask-do
   "Locate notation (ex: \'exists\' _ , _)" "Locate"
   ))

(defun coq-set-undo-limit (undos)
  (proof-shell-invisible-command (format "Set Undo %s . " undos)))

(defun coq-Pwd ()
  "Display the current Coq working directory."
  (interactive)
  (proof-shell-invisible-command "Pwd."))

(defun coq-Inspect ()
  (interactive)
  (coq-ask-do "Inspect how many objects back?" "Inspect" t))

(defun coq-PrintSection()
  (interactive)
  (coq-ask-do "Print Section" "Print Section" t))

(defun coq-Print-implicit ()
  "Ask for an ident and print the corresponding term."
  (interactive)
  (coq-ask-do "Print Implicit" "Print Implicit"))

(defun coq-Check (withprintingall)
  "Ask for a term and print its type.
With flag Printing All if some prefix arg is given (C-u)."
  (interactive "P")
  (if withprintingall
      (coq-ask-do-show-all "Check" "Check")
    (coq-ask-do "Check" "Check")))

(defun coq-Check-show-implicits ()
  "Ask for a term and print its type."
  (interactive)
  (coq-ask-do-show-implicits "Check" "Check"))

(defun coq-Check-show-all ()
  "Ask for a term and print its type."
  (interactive)
  (coq-ask-do-show-all "Check" "Check"))

(defun coq-get-response-string-at (&optional pt)
  "Go forward from PT until reaching a 'response property, and return it.
Response span only starts at first non space character of a
command, so we may have to go forward to find it. Starts
from (point) if pt is nil. Precondition: pt (or point if nil)
must be in locked region."
  (let ((pt (or pt (point))))
    (save-excursion
      (goto-char pt)
      (while (and (not (eq (point) (point-max)))
                  (not (span-at (point) 'response)))
        (forward-char))
      (span-property (span-at (point) 'response) 'response))))

(defun coq-Show (withprintingall)
  "Ask for a number i and show the ith goal.
Ask for a number i and show the ith current goal. With non-nil
prefix argument and not on the locked span, show the goal with
flag Printing All set."
; Disabled:
;  "Ask for a number i and show the ith goal, or show ancient goal.
;If point is on a locked span, show the corresponding coq
;output (i.e. for tactics: the goal after the tactic). Otherwise
;ask for a number i and show the ith current goal. With non-nil
;prefix argument and not on the locked span, show the goal with
;flag Printing All set."
;
  (interactive "P")
  ;; Disabling this as this relies on 'response attribute that is empty when
  ;; the command was processed silently. We should first have a coq command
  ;; asking to print the goal at a given state.
  (if (proof-in-locked-region-p)
      (let ((s (coq-get-response-string-at)))
        (if (zerop (length (coq-get-response-string-at)))
            (message "Cannot show the state at this point: Coq was silent during this command.")
          (set-buffer proof-response-buffer)
          (let ((inhibit-read-only 'titi))
            (pg-response-display s)
            (proof-display-and-keep-buffer proof-response-buffer)
            (coq-optimise-resp-windows))))
    (if withprintingall
        (coq-ask-do-show-all "Show goal number" "Show" t)
      (coq-ask-do "Show goal number" "Show" t))))

(defun coq-Show-with-implicits ()
  "Ask for a number i and show the ith goal."
  (interactive)
  (coq-ask-do-show-implicits "Show goal number" "Show" t))

(defun coq-Show-with-all ()
  "Ask for a number i and show the ith goal."
  (interactive)
  (coq-ask-do-show-all "Show goal number" "Show" t))

;; Check
(eval-when (compile)
  (defvar coq-auto-adapt-printing-width nil)); defpacustom

;; Since Printing Width is a synchronized option in coq (?) it is retored
;; silently to a previous value when retracting. So we reset the stored width
;; when retracting, so that it will be auto-adapted at the next command. Not
;; perfect: we have to forward one step to see the effect.

;; FIXME: hopefully this will eventually become a non synchronized option and
;; we can remove this.
(defun coq-set-auto-adapt-printing-width (&optional symb val); args are for :set compatibility
  "Function called when setting `auto-adapt-printing-width'"
  (setq symb val)
  (if coq-auto-adapt-printing-width
      (progn
        (add-hook 'proof-assert-command-hook 'coq-adapt-printing-width)
        (add-hook 'proof-retract-command-hook 'coq-reset-printing-width))
    (remove-hook 'proof-assert-command-hook 'coq-adapt-printing-width)
    (remove-hook 'proof-retract-command-hook 'coq-reset-printing-width)))


(defpacustom auto-adapt-printing-width t
  "If non-nil, adapt automatically printing width of goals window.
Each timme the user sends abunch of commands to Coq, check if the
width of the goals window changed, and adapt coq printing width.
WARNING: If several windows are displaying the goals buffer, one
is chosen randomly. WARNING 2: when backtracking the printing
width is synchronized by coq (?!)."
  :type 'boolean
  :safe 'booleanp
  :group 'coq
  :eval (coq-set-auto-adapt-printing-width))


;; defpacustom fails to call :eval during inititialization, see trac #456
(coq-set-auto-adapt-printing-width)

;; this initiates auto adapt printing width at start, by reading the config
;; var. Let us put this at the end of hooks to have a chance to read local
;; variables first.
(add-hook 'coq-mode-hook 'coq-auto-adapt-printing-width t)

(defvar coq-shell-current-line-width nil
  "Current line width of the Coq printing width.
Its value will be updated whenever a command is sent if
necessary.")

;; Resetting the known printing width (for when we don't know it, for example
;; when retracting.
(defun coq-reset-printing-width ()
  (setq coq-shell-current-line-width nil))

(defun coq-buffer-window-width (buffer)
  "Return the width of a window currently displaying BUFFER."
  (let*
      ((buf-wins (get-buffer-window-list buffer nil t))
       (dummy (if (not (eq 1 (length buf-wins)))
                  (display-warning
                   'proof-general
                   "Zero or more than one goals window, guessing window width."
                   :debug)))
       (buf-win (car buf-wins)));; TODO return the widest one instead of the first?
    ;; return nil if no goal buffer found
    (and buf-win (window-width buf-win))))


(defun coq-goals-window-width ()
  (coq-buffer-window-width proof-goals-buffer))
(defun coq-response-window-width ()
  (coq-buffer-window-width proof-response-buffer))
 
(defun coq-guess-goal-buffer-at-next-command ()
  "Return the probable width of goals buffer if it pops up now.
This is a guess based on the current width of goals buffer if
present, current pg display mode and current geometry otherwise."
  (let (pol (proof-guess-3win-display-policy proof-three-window-mode-policy))
    (cond
     ;; goals buffer is visible, bingo
     ((coq-goals-window-width))
     ;; Below is the heuristic to guess the good width for goals
     ;; 2 windows mode, response-buffer visible, use this width
     ((and (not proof-three-window-enable) (coq-response-window-width)))
     ;; 2 windows mode, response buffer not visible, give up
     ((not proof-three-window-enable) nil)
     ;; 3 windows mode, one frame, and vertical policy
     ((and proof-three-window-enable (not proof-multiple-frames-enable)
           (eq pol 'vertical))
      (window-width))
     ;; 3 windows mode, one frame, other policies, give up
     ((and proof-three-window-enable (not proof-multiple-frames-enable))
      nil)
     ;; multiple frames. If goals buffer pops up it will have frame default
     ;; size. Falling back to X default window size if not specified.
     ;; This is hard to mimick, let us give up
     (proof-multiple-frames-enable nil)
     (t nil) ;; assert false?
     )))

(defun coq-adapt-printing-width (&optional show width)
  "Sends a Set Printing Width command to coq to fit the response window's width.
A Show command is also issued if SHOW is non-nil, so that the
goal is redisplayed."
  (interactive)
  (let ((wdth (or width (coq-guess-goal-buffer-at-next-command))))
    ;; if no available width, or unchanged, do nothing
    (when (and wdth (not (equal wdth coq-shell-current-line-width)))
      (proof-shell-invisible-command (format "Set Printing Width %S." (- wdth 1)) t)
      (setq coq-shell-current-line-width wdth)
      ;; Show iff show non nil and some proof is under way
      (when (and show (not (null (caddr (coq-last-prompt-info-safe)))))
        (proof-shell-invisible-command (format "Show.") t nil 'no-error-display)))))

(defun coq-adapt-printing-width-and-show(&optional show width)
  (interactive)
  (coq-adapt-printing-width t width))

(defun coq-ask-adapt-printing-width-and-show ()
  (interactive)
  (let* ((deflt (coq-goals-window-width))
         (rd (read-number (format "Width (%S): " deflt) deflt)))
    (coq-adapt-printing-width t rd)))


(defvar coq-highlight-id-last-regexp nil)

(defun coq-highlight-id-in-goals (re)
  (with-current-buffer proof-goals-buffer
    (highlight-regexp re 'lazy-highlight)))

(defun coq-unhighlight-id-in-goals (re)
  (with-current-buffer proof-goals-buffer
    (unhighlight-regexp re)))

(defun coq-highlight-id-at-pt-in-goals ()
  (interactive)
  (let* ((id (coq-id-or-notation-at-point))
         (re (regexp-quote (or id ""))))
    (when coq-highlight-id-last-regexp
      (coq-unhighlight-id-in-goals coq-highlight-id-last-regexp))
    (coq-highlight-id-in-goals re)
    (setq coq-highlight-id-last-regexp re)))


(proof-definvisible coq-PrintHint "Print Hint. ")

;; Items on show menu
(proof-definvisible coq-show-tree "Show Tree.")
(proof-definvisible coq-show-proof "Show Proof.")
(proof-definvisible coq-show-conjectures "Show Conjectures.")
(proof-definvisible coq-show-intros "Show Intros.") ; see coq-insert-intros below
(proof-definvisible coq-set-printing-implicit "Set Printing Implicit.")
(proof-definvisible coq-unset-printing-implicit "Unset Printing Implicit.")
(proof-definvisible coq-set-printing-all "Set Printing All.")
(proof-definvisible coq-unset-printing-all "Unset Printing All.")
(proof-definvisible coq-set-printing-synth "Set Printing Synth.")
(proof-definvisible coq-unset-printing-synth "Unset Printing Synth.")
(proof-definvisible coq-set-printing-coercions "Set Printing Coercions.")
(proof-definvisible coq-unset-printing-coercions "Unset Printing Coercions.")
(proof-definvisible coq-set-printing-wildcards "Set Printing Wildcard.")
(proof-definvisible coq-unset-printing-wildcards "Unset Printing Wildcard.")
; Takes an argument
;(proof-definvisible coq-set-printing-printing-depth "Set Printing Printing Depth . ")
;(proof-definvisible coq-unset-printing-printing-depth "Unset Printing Printing Depth . ")



(defun coq-Compile ()
  "Compiles current buffer."
  (interactive)
  (let* ((n (buffer-name))
         (l (string-match ".v" n)))
    (compile (concat "make " (substring n 0 l) ".vo"))))





;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Holes mode switch
;; TODO: have this plugged agian when we have abbreviation without holes
;; For now holes are always enabled.
;(defpacustom use-editing-holes t
;  "Enable holes for editing."
;  :type 'boolean)


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;   Configuring proof and pbp mode and setting up various utilities  ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


;; General consensus among users: flickering spans are much too annoying
;; compared to the usefulness of tooltips.
;; Set to t to bring it back%%
;;
;; FIXME: this always sets proof-output-tooltips to nil, even if the user puts
;; explicitely the reverse in it sconfig file. I just want to change the
;; *default* value to nil.
(custom-set-default 'proof-output-tooltips nil)

;; This seems xemacs only code, remove?
(defconst coq-prettify-symbols-alist
  '(("not"	. ?¬)
    ;; ("/\\"	. ?∧)
    ("/\\"	. ?⋀)
    ;; ("\\/"	. ?∨)
    ("\\/"	. ?⋁)
    ;;("forall"	. ?∀)
    ("forall"	. ?Π)
    ("fun"	. ?λ)
    ("->"	. ?→)
    ("<-"	. ?←)
    ("=>"	. ?⇒)
    ;; ("~>"	. ?↝) ;; less desirable
    ;; ("-<"	. ?↢) ;; Paterson's arrow syntax
    ;; ("-<"	. ?⤙) ;; nicer but uncommon
    ("::"	. ?∷)
    ))


(defun coq-get-comment-region (pt)
  "Return a list of the forme (beg end) where beg,end is the comment region arount position PT.
Return nil if PT is not inside a comment"
  (save-excursion
    (goto-char pt)
    `(,(save-excursion (coq-find-comment-start))
      ,(save-excursion (coq-find-comment-end)))))

(defun coq-near-comment-region ()
  "Return a list of the forme (beg end) where beg,end is the comment region near position PT.
Return nil if PT is not near a comment.
Near here means PT is either inside or just aside of a comment."
  (save-excursion
    (cond
     ((coq-looking-at-comment)
      (coq-get-comment-region (point)))
     ((and (looking-back proof-script-comment-end)
           (save-excursion (forward-char -1) (coq-looking-at-comment)))
      (coq-get-comment-region (- (point) 1)))
     ((and (looking-at proof-script-comment-start)
           (save-excursion (forward-char) (coq-looking-at-comment)))
      (coq-get-comment-region (+ (point) 1))))))

(defun coq-fill-paragraph-function (n)
  "Coq mode specific fill-paragraph function. Fills only comment at point."
  (let ((reg (coq-near-comment-region)))
    (when reg
      (fill-region (car reg) (cadr reg))))
  t);; true to not fallback to standard fill function

;; TODO (but only for paragraphs in comments)
;; Should recognize coqdoc bullets, stars etc... Unplugged for now.
(defun coq-adaptive-fill-function ()
  (let ((reg (coq-near-comment-region)))
    (save-excursion
      (goto-char (car reg))
      (re-search-forward "\\((\\*+ ?\\)\\( *\\)")
      (let* ((cm-start (match-string 1))
             (cm-prefix (match-string 2)))
        (concat (make-string (length cm-start) ? ) cm-prefix)))))



;;;;;;;;;;;;;;;;;;;;;;;attempt to deal with debug mode ;;;;;;;;;;;;;;;;

;; tries to extract the last debug goal and display it in goals buffer
(defun coq-display-debug-goal ()
  (interactive)
  (with-current-buffer proof-shell-buffer
    (let ((pt (progn (save-excursion (forward-line -1) (point)))))
      (save-excursion
        (re-search-backward "^TcDebug" pt t)
        (re-search-backward "<infomsg>\\|^TcDebug\\|^</prompt>" nil t)
        (when (looking-at "<infomsg>")
          (let ((pt2 (point)))
            (re-search-backward "Goal:\\|^TcDebug\\|^</prompt>" nil t)
            (when (looking-at "Goal")
              (pg-goals-display (buffer-substring (point) pt2) nil))))))))

;; overwrite the generic one, interactive prompt is Debug mode;; try to display
;; the debug goal in the goals buffer.
(defun proof-shell-process-interactive-prompt-regexp ()
  "Action taken when `proof-shell-interactive-prompt-regexp' is observed."
  (when (and (proof-shell-live-buffer)
	     ; not already visible
	     t)
    (switch-to-buffer proof-shell-buffer)
    (coq-display-debug-goal)
    (message "Prover expects input in %s buffer (if debug mode: h<return> for help))" proof-shell-buffer)))


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


(defun coq-mode-config ()
  ;; SMIE needs this.
  (set (make-local-variable 'parse-sexp-ignore-comments) t)
  ;; Coq error messages are thrown off by TAB chars.
  (set (make-local-variable 'indent-tabs-mode) nil)
  ;; Coq defninition never start by a parenthesis
  (set (make-local-variable 'open-paren-in-column-0-is-defun-start) nil)
  ;; do not break lines in code when filling
  (set (make-local-variable 'fill-nobreak-predicate)
       (lambda () (not (nth 4 (syntax-ppss)))))
  ;; coq mode specific indentation function
  (set (make-local-variable 'fill-paragraph-function) 'coq-fill-paragraph-function)

  ;; TODO (but only for paragraphs in comments)
  ;; (set (make-local-variable 'paragraph-start)  "[ 	]*\\((\\**\\|$\\)")
  ;; (set (make-local-variable 'paragraph-separate) "\\**) *$\\|$")
  ;; (set (make-local-variable 'adaptive-fill-function) 'coq-adaptive-fill-function)

  ;; coq-mode colorize errors better than the generic mechanism
  (setq proof-script-color-error-messages nil)
  (setq proof-terminal-string ".")
  (setq proof-script-command-end-regexp coq-script-command-end-regexp)
  (setq proof-script-parse-function 'coq-script-parse-function)
  (setq proof-script-comment-start "(*")
  (setq proof-script-comment-end "*)")
  (setq proof-script-insert-newlines nil)
  (set (make-local-variable 'comment-start-skip)  "(\\*+ *")
  (set (make-local-variable 'comment-end-skip) " *\\*+)")
  (setq proof-unnamed-theorem-name "Unnamed_thm") ; Coq's default name

  (setq proof-assistant-home-page coq-www-home-page)

  (setq proof-prog-name coq-prog-name)
  (setq proof-guess-command-line 'coq-guess-command-line)
  (setq proof-prog-name-guess t)

  ;; We manage file saveing via coq-compile-auto-save and for coq
  ;; it is not necessary to save files when starting a new buffer.
  (setq proof-query-file-save-when-activating-scripting nil)
  
  ;; Commands sent to proof engine
  (setq proof-showproof-command "Show. "
        proof-context-command "Print All. "
        proof-goal-command "Goal %s. "
        proof-save-command "Save %s. "
        proof-find-theorems-command "Search %s. ")
;; FIXME da: Does Coq have a help or about command?
;;	proof-info-command "Help"

  (setq proof-goal-command-p 'coq-goal-command-p
        proof-find-and-forget-fn 'coq-find-and-forget
        pg-topterm-goalhyplit-fn 'coq-goal-hyp
        proof-state-preserving-p 'coq-state-preserving-p)

  (setq proof-query-identifier-command "Check %s.")
  ;;TODO: from v8.5 this wold be better:
  ;;(setq proof-query-identifier-command "About %s.")

  (setq proof-save-command-regexp coq-save-command-regexp
        proof-really-save-command-p 'coq-save-command-p ;pierre:deals with Proof <term>.
	proof-save-with-hole-regexp coq-save-with-hole-regexp
	proof-goal-with-hole-regexp coq-goal-with-hole-regexp
	proof-nested-undo-regexp coq-state-changing-commands-regexp
        proof-script-imenu-generic-expression coq-generic-expression)

  (when (fboundp 'smie-setup) ; always use smie, old indentation code removed
    (smie-setup coq-smie-grammar #'coq-smie-rules
                  :forward-token #'coq-smie-forward-token
                  :backward-token #'coq-smie-backward-token))

  ;; old indentation code.
  ;; (require 'coq-indent)
  ;; (setq
  ;;  ;; indentation is implemented in coq-indent.el
  ;;  indent-line-function 'coq-indent-line
  ;;  proof-indent-any-regexp      coq-indent-any-regexp
  ;;  proof-indent-open-regexp     coq-indent-open-regexp
  ;;  proof-indent-close-regexp    coq-indent-close-regexp)
  ;; (make-local-variable 'indent-region-function)
  ;; (setq indent-region-function 'coq-indent-region)
  
  

  ;; span menu
  (setq proof-script-span-context-menu-extensions 'coq-create-span-menu)

  (setq proof-shell-start-silent-cmd "Set Silent. "
        proof-shell-stop-silent-cmd "Unset Silent. ")

  (coq-init-syntax-table)
  ;; we can cope with nested comments
  (set (make-local-variable 'comment-quote-nested) nil)

  ;; font-lock
  (setq proof-script-font-lock-keywords coq-font-lock-keywords-1)

  ;; FIXME: have abbreviation without holes
  ;(if coq-use-editing-holes (holes-mode 1))
  (holes-mode 1)

  ;; prooftree config
  (setq
   proof-tree-configured t
   proof-tree-get-proof-info 'coq-proof-tree-get-proof-info
   proof-tree-find-begin-of-unfinished-proof
     'coq-find-begin-of-unfinished-proof)

  (proof-config-done)

  ;; outline
  (set (make-local-variable 'outline-regexp) coq-outline-regexp)
  (set (make-local-variable 'outline-heading-end-regexp)
       coq-outline-heading-end-regexp)

  ;; tags
  (if (file-exists-p coq-tags)
      (set (make-local-variable 'tags-table-list)
           (cons coq-tags tags-table-list)))
  
  (set (make-local-variable 'blink-matching-paren-dont-ignore-comments) t)

  (when coq-may-use-prettify
    (set (make-local-variable 'prettify-symbols-alist)
         coq-prettify-symbols-alist))

  (setq proof-cannot-reopen-processed-files nil)

  (add-hook 'proof-activate-scripting-hook 'proof-cd-sync nil t))

(defun coq-shell-mode-config ()
  (setq
   proof-shell-cd-cmd coq-shell-cd
   proof-shell-filename-escapes '(("\\\\" . "\\\\") ("\""   . "\\\""))
   proof-shell-clear-goals-regexp coq-shell-proof-completed-regexp
   proof-shell-proof-completed-regexp coq-shell-proof-completed-regexp
   proof-shell-error-regexp coq-error-regexp
   proof-shell-interrupt-regexp coq-interrupt-regexp
   proof-shell-assumption-regexp coq-id
   pg-subterm-first-special-char ?\360
   ;; The next three represent path annotation information
   pg-subterm-start-char ?\372          ; not done
   pg-subterm-sep-char ?\373            ; not done
   pg-subterm-end-char ?\374            ; not done
   pg-topterm-regexp "\375"

   ;; FIXME: ideally, the eager annotation should just be a single "special" char,
   ;; this requires changes in Coq.
   proof-shell-eager-annotation-start coq-shell-eager-annotation-start
   proof-shell-eager-annotation-start-length 32

   proof-shell-interactive-prompt-regexp "TcDebug "

   ;; ****** is added at the end of warnings in emacs mode, this is temporary I
   ;;        want xml like tags, and I want them removed before warning display.
   ;; I want the same for errors -> pgip

   proof-shell-eager-annotation-end "\377\\|done\\]\\|</infomsg>\\|\\*\\*\\*\\*\\*\\*\\|) >" ; done
   proof-shell-annotated-prompt-regexp coq-shell-prompt-pattern
   proof-shell-result-start "\372 Pbp result \373"
   proof-shell-result-end "\372 End Pbp result \373"

;   proof-shell-start-goals-regexp          "^\\(?:(dependent evars:[^)]*)\\s-+\\)?[0-9]+\\(?: focused\\)? subgoals?"
   proof-shell-start-goals-regexp          "[0-9]+\\(?: focused\\)? subgoals?"
   proof-shell-end-goals-regexp
   (if coq-hide-additional-subgoals
       (setq proof-shell-end-goals-regexp coq-end-goals-regexp-hide-subgoals)
     (setq proof-shell-end-goals-regexp coq-end-goals-regexp-show-subgoals))

   proof-shell-init-cmd coq-shell-init-cmd

   proof-no-fully-processed-buffer t

   ;; Coq has no global settings?
   ;; (proof-assistant-settings-cmd)

   proof-shell-restart-cmd coq-shell-restart-cmd
   pg-subterm-anns-use-stack t)

  (coq-init-syntax-table)
  ;; (holes-mode 1)  da: does the shell really need holes mode on?
  (setq proof-shell-font-lock-keywords 'coq-font-lock-keywords-1)

  ;; prooftree config
  (setq
   proof-tree-ignored-commands-regexp coq-proof-tree-ignored-commands-regexp
   proof-tree-navigation-command-regexp coq-navigation-command-regexp
   proof-tree-cheating-regexp coq-proof-tree-cheating-regexp
   proof-tree-new-layer-command-regexp coq-proof-tree-new-layer-command-regexp
   proof-tree-current-goal-regexp coq-proof-tree-current-goal-regexp
   proof-tree-update-goal-regexp coq-proof-tree-update-goal-regexp
   proof-tree-existential-regexp coq-proof-tree-existential-regexp
   proof-tree-existentials-state-start-regexp
                      coq-proof-tree-existentials-state-start-regexp
   proof-tree-existentials-state-end-regexp
                        coq-proof-tree-existentials-state-end-regexp
   proof-tree-additional-subgoal-ID-regexp
                              coq-proof-tree-additional-subgoal-ID-regexp
   proof-tree-branch-finished-regexp coq-proof-tree-branch-finished-regexp
   proof-tree-extract-instantiated-existentials
     'coq-extract-instantiated-existentials
   proof-tree-show-sequent-command 'coq-show-sequent-command
   proof-tree-find-undo-position 'coq-proof-tree-find-undo-position
   )
        
  (proof-shell-config-done))


(proof-eval-when-ready-for-assistant
    (easy-menu-define proof-goals-mode-aux-menu
      proof-goals-mode-map
      "Menu for Proof General goals buffer."
      (cons "Coq" coq-other-buffers-menu-entries)))

(proof-eval-when-ready-for-assistant
    (easy-menu-define proof-goals-mode-aux-menu
      proof-response-mode-map
      "Menu for Proof General response buffer."
      (cons "Coq" coq-other-buffers-menu-entries)))


(defun coq-goals-mode-config ()
  (setq pg-goals-change-goal "Show %s . ")
  (setq pg-goals-error-regexp coq-error-regexp)
  (coq-init-syntax-table)
  (setq proof-goals-font-lock-keywords coq-goals-font-lock-keywords)
  (proof-goals-config-done))

(defun coq-response-config ()
  (coq-init-syntax-table)
  (setq proof-response-font-lock-keywords coq-response-font-lock-keywords)
  ;; The line wrapping in this buffer just seems to make it less readable.
  (setq truncate-lines t)
  (proof-response-config-done))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Flags and other settings for Coq.
;; These appear on the Coq -> Setting menu.
;;

;; FIXME da: we should send this command only inside a proof,
;; otherwise it gives an error message.  It should be on
;; a different menu command.
;; (defpacustom print-only-first-subgoal  nil
;;  "Whether to just print the first subgoal in Coq."
;;  :type 'boolean
;;  :setting ("Focus. " . "Unfocus. "))


(defpacustom hide-additional-subgoals nil
  "Show all subgoals if off, show only the current goal if on."
  :type 'boolean
  :safe 'booleanp
  :eval (coq-hide-additional-subgoals-switch))


;
;;; FIXME: to handle "printing all" properly, we should change the state
;;; of the variables that also depend on it.
;;; da:

;;; pc: removed it and others of the same kind. Put an "option" menu instead,
;;; with no state variable. To have the state we should use coq command that
;;; output the value of the variables.
;(defpacustom print-fully-explicit nil
;  "Print fully explicit terms."
;  :type 'boolean
;  :setting ("Set Printing All. " . "Unset Printing All. "))
;

(defpacustom printing-depth 50
  "Depth of pretty printer formatting, beyond which dots are displayed."
  :type 'integer
  :setting "Set Printing Depth %i . ")

;;; Obsolete:
;;(defpacustom undo-depth coq-default-undo-limit
;;  "Depth of undo history.  Undo behaviour will break beyond this size."
;;  :type 'integer
;;  :setting "Set Undo %i . ")

(defun coq-set-search-blacklist (s)
  (let ((res (format "Remove Search Blacklist %s. \nAdd Search Blacklist %s. "
          coq-search-blacklist-string-prev s)))
    (setq coq-search-blacklist-string-prev coq-search-blacklist-string)
    res))


(defun coq-get-search-blacklist (s)
  coq-search-blacklist-string)


(defpacustom search-blacklist coq-search-blacklist-string
  "Strings to blacklist in requests to coq environment."
  :type 'string
  :get coq-search-blacklist-string
  :setting coq-set-search-blacklist)


(defpacustom time-commands nil
  "Whether to display timing information for each command."
  :type 'boolean
  :eval (coq-time-commands-switch))



;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; prooftree support
;;

(defun coq-proof-tree-get-proof-info ()
  "Coq instance of `proof-tree-get-proof-info'."
  (let* ((info (or (coq-last-prompt-info-safe) '(0 0 nil nil))))
         ;; info is now a list with
         ;; * the state number
         ;; * the proof stack depth
         ;; * the list of all open proofs
         ;; * the name of the current proof or nil
    (list (car info) (nth 3 info))))

(defun coq-extract-instantiated-existentials (start end)
  "Coq specific function for `proof-tree-extract-instantiated-existentials'.
Returns the list of currently instantiated existential variables."
  (proof-tree-extract-list
   start end
   coq-proof-tree-existentials-state-start-regexp
   coq-proof-tree-existentials-state-end-regexp
   coq-proof-tree-instantiated-existential-regexp))

(defun coq-show-sequent-command (sequent-id)
  "Coq specific function for `proof-tree-show-sequent-command'."
  (format "Show Goal \"%s\"." sequent-id))

(defun coq-proof-tree-get-new-subgoals ()
  "Check for new subgoals and issue appropriate Show commands.
This is a hook function for `proof-tree-urgent-action-hook'. This
function examines the current goal output and searches for new
unknown subgoals. Those subgoals have been generated by the last
proof command and we must send their complete sequent text
eventually to prooftree. Because subgoals may change with
the next proof command, we must execute the additionally needed
Show commands before the next real proof command.

The ID's of the open goals are checked with
`proof-tree-sequent-hash' in order to find out if they are new.
For any new goal an appropriate Show Goal command with a
'proof-tree-show-subgoal flag is inserted into
`proof-action-list'. Then, in the normal delayed output
processing, the sequent text is send to prooftree as a sequent
update (see `proof-tree-update-sequent') and the ID of the
sequent is registered as known in `proof-tree-sequent-hash'.

Searching for new subgoals must only be done when the proof is
not finished, because Coq 8.5 lists open existential variables
as (new) open subgoals. For this test we assume that
`proof-marker' has not yet been moved.

The not yet delayed output is in the region
\[proof-shell-delayed-output-start, proof-shell-delayed-output-end]."
  ;; (message "CPTGNS start %s end %s"
  ;;          proof-shell-delayed-output-start
  ;;          proof-shell-delayed-output-end)
  (with-current-buffer proof-shell-buffer
    (let ((start proof-shell-delayed-output-start)
          (end proof-shell-delayed-output-end))
      ;; The message "All the remaining goals are on the shelf" is processed as
      ;; urgent message and is therefore before
      ;; proof-shell-delayed-output-start. We therefore need to go back to
      ;; proof-marker.
      (goto-char proof-marker)
      (unless (proof-re-search-forward
               coq-proof-tree-branch-finished-regexp end t)
        (goto-char start)
        (while (proof-re-search-forward
                coq-proof-tree-additional-subgoal-ID-regexp end t)
          (let ((subgoal-id (match-string-no-properties 1)))
            (unless (gethash subgoal-id proof-tree-sequent-hash)
              (message "CPTGNS new sequent %s found" subgoal-id)
              (setq proof-action-list
                    (cons (proof-shell-action-list-item
                           (coq-show-sequent-command subgoal-id)
                           (proof-tree-make-show-goal-callback (car proof-info))
                           '(no-goals-display
                             no-response-display
                             proof-tree-show-subgoal))
                          proof-action-list)))))))))
  
(add-hook 'proof-tree-urgent-action-hook 'coq-proof-tree-get-new-subgoals)


(defun coq-find-begin-of-unfinished-proof ()
  "Return start position of current unfinished proof or nil."
  (let ((span (span-at (1- (proof-unprocessed-begin)) 'type)))
    ;; go backward as long as we are inside the proof
    ;; the proofstack property is set inside the proof
    ;; the command before the proof has the goalcmd property
    (while (and span
                (span-property span 'proofstack)
                (not (span-property span 'goalcmd)))
          (setq span (span-at (1- (span-start span)) 'type)))
    ;; Beware of completed proofs! They have type goalsave and for
    ;; strange reasons the whole completed proof has the goalcmd property.
    (if (and span
             (not (eq 'goalsave (span-property span 'type)))
             (span-property span 'goalcmd))
        (span-start span)
      nil)))
    
(defun coq-proof-tree-find-undo-position (state)
  "Return the position for undo state STATE.
This is the Coq incarnation of `proof-tree-find-undo-position'."
  (let ((span-res nil)
        (span-cur (span-at (1- (proof-unprocessed-begin)) 'type))
        (state (1- state)))
    ;; go backward as long as the statenum property in the span is greater or
    ;; equal than state
    (while (<= state (span-property span-cur 'statenum))
      (setq span-res span-cur)
      (setq span-cur (span-at (1- (span-start span-cur)) 'type)))
    (span-start span-res)))


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Pre-processing of input string
;;


(defconst coq--time-prefix "Time "
  "Coq command prefix for displaying timing information.")

(defun coq-bullet-p (s)
  (string-match coq-bullet-regexp-nospace s))

;; Remark: `action' and `string' are known by `proof-shell-insert-hook'
(defun coq-preprocessing ()
  (when coq-time-commands
    (with-no-warnings  ;; NB: dynamic scoping of `string' and `action'
      ;; Don't add the prefix if this is a command sent internally
      (unless (or (eq action 'proof-done-invisible)
                  (coq-bullet-p string)) ;; coq does not accept "Time -".
        (setq string (concat coq--time-prefix string))))))

(add-hook 'proof-shell-insert-hook 'coq-preprocessing)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Subterm markup -- it was added to Coq by Healf, but got removed.
;;                   Let's try faking something by regexp matching.

;; FIXME: not operational yet
(defun coq-fake-constant-markup ()
  "Markup constants in Coq goal output by matching on regexps.
This is a horrible and approximate way of doing subterm markup.
\(Code used to be in Coq, but got lost between versions 5 and 7).
This is a hook setting for `pg-after-fontify-output-hook' to
enable identifiers to be highlighted and allow useful
mouse activation."
  (goto-char (point-min))
  (while (re-search-forward "\(\w+[^\w]\)" nil t)
    (replace-match "\372\200\373\\1\374" nil t)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Context-senstive in-span menu additions
;;

(defun coq-create-span-menu (span idiom name)
  (if (eq idiom 'proof)
      (let ((thm (span-property span 'name)))
        (list (vector
               "Check" ; useful?
               `(proof-shell-invisible-command
                 ,(format "Check %s." thm)))
              (vector
               "Print"
               `(proof-shell-invisible-command
                 ,(format "Print %s." thm)))))))


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Some smart insertion functions
;;

(defconst module-kinds-table
  '(("Section" 0) ("Module" 1) ("Module Type" 2) ("Declare Module" 3))
  "Enumerates the different kinds of modules.")

(defconst modtype-kinds-table
  '(("" 1) (":" 2) ("<:" 3))
  "Enumerates the different kinds of type information for modules.")

(defun coq-postfix-.v-p (s)
  (string-match-p "\\.v\\'" s))

(defun coq-directories-files (l)
  (let* ((file-list-list (mapcar 'directory-files l))
         (file-list (apply 'append file-list-list))
         (filtered-list (remove-if-not 'coq-postfix-.v-p file-list)))
  filtered-list))

(defun coq-remove-dot-v-extension (s)
  (substring s 0 -2))

(defun coq-load-path-to-paths (ldpth)
  (if (listp ldpth) (car ldpth) ldpth))

(defun coq-build-accessible-modules-list ()
  (let* ((pth (or coq-load-path '(".")))
         (cleanpth (mapcar 'coq-load-path-to-paths pth))
         (existingpth (remove-if-not 'file-exists-p cleanpth))
         (file-list (coq-directories-files existingpth)))
    (mapcar 'coq-remove-dot-v-extension file-list)))

(defun coq-insert-section-or-module ()
  "Insert a module or a section after asking right questions."
  (interactive)
  (let*
      ((mods (completing-read "Kind of module (TAB to see list): "
                              module-kinds-table))
       (s (read-string  "Name: "))
       (typkind (if (string-equal mods "Section")
                    "" ;; if not a section
                  (completing-read "Kind of type (optional, TAB to see list): "
                                   modtype-kinds-table)))
       (p (point)))
    (if (string-equal typkind "")
        (progn
          (insert mods " " s ".\n#\nEnd " s ".")
          (holes-replace-string-by-holes-backward p)
          (goto-char p))
      (insert mods " " s " " typkind " #.\n#\nEnd " s ".")
      (holes-replace-string-by-holes-backward p)
      (goto-char p)
      (holes-set-point-next-hole-destroy))))

(defconst reqkinds-kinds-table
  '(("Require Import") ("Require Export") ("Require") ("Import"))
  "Enumerates the different kinds of requiring a module.")

(defun coq-insert-requires ()
  "Insert requires to modules, iteratively."
  (interactive)
  (let* ((s)
         (reqkind
          (completing-read
           "Command (TAB to see list, default Require Import) : "
           reqkinds-kinds-table nil nil nil nil "Require Import")))
    (loop do
          (setq s (completing-read "Name (empty to stop) : "
                                   (coq-build-accessible-modules-list)))
          (unless (zerop (length s)) (insert (format "%s %s.\n" reqkind s)))
          while (not (string-equal s "")))))

;; TODO add module closing
(defun coq-end-Section ()
  "Ends a Coq section."
  (interactive)
  (let ((count 1)) ; The number of section already "Ended" + 1
    (let ((section
	   (save-excursion
	     (progn
	       (while (and (> count 0)
			   (search-backward-regexp
			    "Chapter\\|Section\\|End" 0 t))
		 (if (char-equal (char-after (point)) ?E)
		     (setq count (1+ count))
		   (setq count (1- count))))
	       (buffer-substring-no-properties
          (progn (beginning-of-line) (forward-word 1) (point))
          (progn (end-of-line) (point)))))))
      (insert (concat "End" section)))))

(defun coq--format-intros (output)
  "Create an “intros” form from the OUTPUT of “Show Intros”."
  (let* ((shints (replace-regexp-in-string "[\r\n ]*\\'" "" output)))
    (if (or (string= "" shints)
            (string-match coq-error-regexp shints))
        (error "Don't know what to intro")
      (format "intros %s" shints))))

(defun coq-insert-intros ()
  "Insert an intros command with names given by Show Intros.
Based on idea mentioned in Coq reference manual."
  (interactive)
  (let* ((output (proof-shell-invisible-cmd-get-result "Show Intros.")))
    (indent-region (point)
                   (progn (insert (coq--format-intros output))
                          (save-excursion
                            (insert (if coq-one-command-per-line "\n" " "))
                            (point))))
    ;; `proof-electric-terminator' moves the point in all sorts of strange
    ;; ways, so we run it last
    (let ((last-command-event ?.)) ;; Insert a dot
      (proof-electric-terminator))))

(defvar coq-keywords-accepting-as-regex (regexp-opt '("induction" "destruct" "inversion" "injection")))

;; destruct foo., where foo is a name.
(defvar coq-auto-as-hack-hyp-name-regex 
  (concat "\\(" "induction\\|destruct" "\\)\\s-+\\(" coq-id-shy "\\)\\s-*\\.")
  "Regexp of commands needing a hack to generate correct \"as\" close.
tacitcs like destruct and induction reuse hypothesis names by
default, which makes the detection of new hypothesis incorrect.
the hack consists in adding the \"!\" modifier on the argument
destructed, so that it is left in the goal and the name cannot be
reused. We also had a \"clear\" at the end of the tactic so that
the whole tactic behaves correctly.
Warning: this makes the error messages (and location) wrong.")

(defun coq-hack-cmd-for-infoH (s)
  "return the tactic S hacked with infoH tactical."
  (cond
   ((string-match ";" s) s) ;; composed tactic cannot be treated 
   ((string-match coq-auto-as-hack-hyp-name-regex s)
    (concat "infoH " (match-string 1 s) " (" (match-string 2 s) ")."))
   ((string-match coq-keywords-accepting-as-regex s)
    (concat "infoH " s))
   (t (concat "infoH " s))))

;; Point supposed to be at the end of locked region, that is
;; (proof-assert-next-command-interactive) has just finished
(defun coq-tactic-already-has-an-as-close(s)
  "Return t if the last tactic of locked region contains an \"as\" close."
  (save-excursion (string-match "\\<as\\>" s)))


(defun coq-insert-as-in-next-command ()
  (interactive)
  (save-excursion
    (goto-char (proof-unprocessed-begin))
    (coq-find-real-start)
    (let* ((pt (point))
           (dummy (coq-script-parse-cmdend-forward))
           (cmd (buffer-substring pt (point)))
           (newcmd (if (coq-tactic-already-has-an-as-close cmd)
                       nil
                     (coq-hack-cmd-for-infoH cmd))))
      (when newcmd ; FIXME: we stop if as already there, replace it instead?
        (proof-shell-invisible-command newcmd t)
        (let* ((str (string-match "<infoH>\\([^<]*\\)</infoH>"
                                  ;; proof-shell-last-response-output would be
                                  ;; smaller/faster but since this message is output
                                  ;; *before* resulting goals, it is not detected as
                                  ;; a response message.
                                  proof-shell-last-output))
               (substr  (or (and str (match-string 1 proof-shell-last-output)) ""))
               ;; emptysubstr = t if substr is empty or contains only spaces and |
               (emptysubstr (and (string-match "\\(\\s-\\||\\)*" substr)
                                 (eq (length substr) (length (match-string 0 substr)))))) ; idem
          (unless (or emptysubstr (coq-tactic-already-has-an-as-close newcmd)) ;; FIXME
            (save-excursion
              ;; TODO: look for eqn:XX and go before it.
              ;; Go just before the last "."
              (goto-char (proof-unprocessed-begin))
              (coq-script-parse-cmdend-forward)
              (coq-script-parse-cmdend-backward)
              (insert (concat " as [" substr "]")))))))))

;; Trying to propose insertion of "as" for a whole region. But iterating
;; proof-assert-next-command-interactive is probably wrong if some error occur
;; during scripting.
;; (defun coq-insert-as-in-region (&optional beg end)
;;   (interactive "r")
;;   (let ((beg (or beg (point-min)))
;;         (end (or end (point-max))))
;;     (goto-char beg)
;;     (while (< (point) end)
;;       (coq-script-parse-cmdend-forward)
;;       (coq-insert-as-in-next-command)
;;       (proof-assert-next-command-interactive))))



(defun coq-insert-match ()
  "Insert a match expression from a type name by Show Match.
Based on idea mentioned in Coq reference manual.
Also insert holes at insertion positions."
  (interactive)
  (proof-shell-ready-prover)
  (let* ((cmd))
    (setq cmd (read-string "Build match for type: "))
    (let* ((thematch
           (proof-shell-invisible-cmd-get-result (concat "Show Match " cmd ".")))
           (match (replace-regexp-in-string "=> \n" "=> #\n" thematch)))
      ;; if error, it will be displayed in response buffer (see def of
      ;; proof-shell-invisible-cmd-get-result), otherwise:
      (unless (proof-string-match coq-error-regexp match)
        (let ((start (point)))
          (insert match)
          (indent-region start (point) nil)
          (let ((n (holes-replace-string-by-holes-backward start)))
            (case n
	(0 nil)				; no hole, stay here.
	(1
	 (goto-char start)
	 (holes-set-point-next-hole-destroy)) ; if only one hole, go to it.
	(t
	 (goto-char start)
	 (message
          (substitute-command-keys
           "\\[holes-set-point-next-hole-destroy] to jump to active hole.  \\[holes-short-doc] to see holes doc."))))))))))

(defun coq-insert-solve-tactic ()
  "Ask for a closing tactic name, with completion, and insert at point.
Completion is on a quasi-exhaustive list of Coq closing tactics."
  (interactive)
  (coq-insert-from-db coq-solve-tactics-db "Closing tactic"))

(defun coq-insert-tactic ()
  "Insert a tactic name at point, with completion.
Questions may be asked to the user to select the tactic."
  (interactive)
  (coq-insert-from-db coq-tactics-db "Tactic"))

(defun coq-insert-tactical ()
  "Ask for a closing tactic name, with completion, and insert at point.
Completion is on a quasi-exhaustive list of Coq tacticals."
  (interactive)
  (coq-insert-from-db coq-tacticals-db "Tactical"))

(defun coq-insert-command ()
  "Ask for a command name, with completion, and insert it at point."
  (interactive)
  (coq-insert-from-db coq-commands-db "Command"))

(defun coq-insert-term ()
  "Ask for a term kind, with completion, and insert it at point."
  (interactive)
  (coq-insert-from-db coq-terms-db "Kind of term"))


(defun coq-query (showall)
  "Ask for a query, with completion, and send to Coq."
  (interactive "P")
  (let ((q (coq-build-command-from-db coq-queries-commands-db "which Query?")))
    (if showall
        (coq-command-with-set-unset
         "Set Printing All" q "Unset Printing All" nil "Test Printing All")
      (proof-shell-invisible-command q))))


;; Insertion commands
(define-key coq-keymap [(control ?i)] 'coq-insert-intros)
(define-key coq-keymap [(control ?m)] 'coq-insert-match)
(define-key coq-keymap [(control ?()] 'coq-insert-section-or-module)
(define-key coq-keymap [(control ?))] 'coq-end-Section)
(define-key coq-keymap [(control ?t)] 'coq-insert-tactic)
(define-key coq-keymap [?t] 'coq-insert-tactical)
(define-key coq-keymap [?!] 'coq-insert-solve-tactic) ; will work in tty
(define-key coq-keymap [(control ?\s)] 'coq-insert-term)
(define-key coq-keymap [(control return)] 'coq-insert-command)
(define-key coq-keymap [(control ?q)] 'coq-query)
(define-key coq-keymap [(control ?r)] 'coq-insert-requires)
; [ for "as [xxx]" is easy to remember, ccontrol-[ would be better but hard to type on french keyboards
; anyway company-coq should provide an "as!<TAB>". 
(define-key coq-keymap [(?\[)] 'coq-insert-as-in-next-command) ;; not for goal/response buffer?

; Query commands
(define-key coq-keymap [(control ?s)] 'coq-Show)
(define-key coq-keymap [?r] 'proof-store-response-win)
(define-key coq-keymap [?g] 'proof-store-goals-win)
(define-key coq-keymap [(control ?o)] 'coq-SearchIsos)
(define-key coq-keymap [(control ?p)] 'coq-Print)
(define-key coq-keymap [(control ?b)] 'coq-About)
(define-key coq-keymap [(control ?a)] 'coq-SearchAbout)
(define-key coq-keymap [(control ?c)] 'coq-Check)
(define-key coq-keymap [?h] 'coq-PrintHint)
(define-key coq-keymap [(control ?l)] 'coq-LocateConstant)
(define-key coq-keymap [(control ?n)] 'coq-LocateNotation)
(define-key coq-keymap [(control ?w)] 'coq-ask-adapt-printing-width-and-show)

;(proof-eval-when-ready-for-assistant
; (define-key ??? [(control c) (control a)] (proof-ass keymap)))

;(proof-eval-when-ready-for-assistant
; (define-key ??? [(control c) (control a)] (proof-ass keymap)))

(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?c)] 'coq-Check)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?p)] 'coq-Print)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?o)] 'coq-SearchIsos)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?b)] 'coq-About)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?a)] 'coq-SearchAbout)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?s)] 'coq-Show)
(define-key coq-goals-mode-map [(control ?c)(control ?a)?r] 'proof-store-response-win)
(define-key coq-goals-mode-map [(control ?c)(control ?a)?g] 'proof-store-goals-win)
(define-key coq-goals-mode-map [(control ?c)(control ?a)?h] 'coq-PrintHint)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?q)] 'coq-query)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?w)] 'coq-ask-adapt-printing-width-and-show)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?l)] 'coq-LocateConstant)
(define-key coq-goals-mode-map [(control ?c)(control ?a)(control ?n)] 'coq-LocateNotation)


(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?c)] 'coq-Check)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?p)] 'coq-Print)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?o)] 'coq-SearchIsos)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?b)] 'coq-About)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?a)] 'coq-SearchAbout)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?s)] 'coq-Show)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?r)] 'proof-store-response-win)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?g)] 'proof-store-goals-win)
(define-key coq-response-mode-map [(control ?c)(control ?a)?h] 'coq-PrintHint)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?q)] 'coq-query)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?w)] 'coq-ask-adapt-printing-width-and-show)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?l)] 'coq-LocateConstant)
(define-key coq-response-mode-map [(control ?c)(control ?a)(control ?n)] 'coq-LocateNotation)

(when coq-remap-mouse-1
  (define-key proof-mode-map [(control down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-mode-map [(shift down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-mode-map [(control mouse-1)] '(lambda () (interactive)))
  (define-key proof-mode-map [(shift mouse-1)] '(lambda () (interactive)))
  (define-key proof-mode-map [(control shift down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-mode-map [(control shift mouse-1)] '(lambda () (interactive)))

  (define-key proof-response-mode-map [(control down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-response-mode-map [(shift down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-response-mode-map [(control mouse-1)] '(lambda () (interactive)))
  (define-key proof-response-mode-map [(shift mouse-1)] '(lambda () (interactive)))
  (define-key proof-response-mode-map [(control shift down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-response-mode-map [(control shift mouse-1)] '(lambda () (interactive)))

  (define-key proof-goals-mode-map [(control down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-goals-mode-map [(shift down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-goals-mode-map [(control mouse-1)] '(lambda () (interactive)))
  (define-key proof-goals-mode-map [(shift mouse-1)] '(lambda () (interactive)))
  (define-key proof-goals-mode-map [(control shift down-mouse-1)] 'coq-id-under-mouse-query)
  (define-key proof-goals-mode-map [(control shift mouse-1)] '(lambda () (interactive))))

;;;;;;;;;;;;;;;;;;;;;;;;
;; error handling
;;;;;;;;;;;;;;;;;;;;;;;;


(defvar last-coq-error-location nil
  "Last error from `coq-get-last-error-location' and `coq-highlight-error'.")


;; I don't use proof-shell-last-ouput here since it is not always set to the
;; really last output (specially when a *tactic* gives an error) instead I go
;; directly to the response buffer. This allows also to clean the response
;; buffer (better to only scroll it?)
(defun coq-get-last-error-location (&optional parseresp clean)
  "Return location information on last error sent by coq.
Return a two elements list (POS LEN) if successful, nil otherwise.
POS is the number of characters preceding the underlined expression,
and LEN is its length.
Coq error message must be like this:

\"
> command with an error here ...
>                       ^^^^
\"

If PARSERESP is nil, don't really parse response buffer but take the value of
`last-coq-error-location' instead, otherwise parse response buffer and updates
`last-coq-error-location'.

If PARSERESP and CLEAN are non-nil, delete the error location from the response
buffer."
  (if (not parseresp) last-coq-error-location
    ;; proof-shell-handle-error-or-interrupt-hook is called from shell buffer
    ;; then highlight the corresponding error location
    (proof-with-current-buffer-if-exists proof-response-buffer
      (goto-char (point-max)) ;\nToplevel input, character[^:]:\n
      (when (re-search-backward "^Toplevel input[^:]+:\n> \\(.*\\)\n> \\([^^]*\\)\\(\\^+\\)\n" nil t)
        (let ((text (match-string 1))
              (pos (length (match-string 2)))
              (len (length (match-string 3))))
          ;; clean the response buffer from ultra-ugly underlined command line
          ;; parsed above. Don't kill the first \n
          (let ((inhibit-read-only t))
            (when clean (delete-region (match-beginning 0) (match-end 0))))
          (when proof-shell-unicode ;; TODO: remove this (when...) when coq-8.3 is out.
            ;; `pos' and `len' are actually specified in bytes, apparently. So
            ;; let's convert them, assuming the encoding used is utf-8.
            ;; Presumably in Emacs-23 we could use `string-bytes' for that
            ;; since the internal encoding happens to use utf-8 as well.
            ;; Actually in coq-8.3 one utf8 char = one space so we do not need
            ;; this at all
            (let ((bytes text)) ;(encode-coding-string text 'utf-8-unix)
              ;; Check that pos&len make sense in `bytes', if not give up.
              (when (>= (length bytes) (+ pos len))
                ;; We assume here that `text' is a single line and use \n as
                ;; a marker so we can find it back after decoding.
                (setq bytes (concat (substring bytes 0 pos)
                                    "\n" (substring bytes pos (+ pos len))))
                (let ((chars (decode-coding-string bytes 'utf-8-unix)))
                  (setq pos (string-match "\n" chars))
                  (setq len (- (length chars) pos 1))))))
          (setq last-coq-error-location (list pos len)))))))


(defun coq-highlight-error (&optional parseresp clean)
  "Parses the last coq output looking at an error message. Highlight the text
pointed by it. Coq error message must be like this:

\"
> command with an error here ...
>                       ^^^^
\"

If PARSERESP is nil, don't really parse response buffer but take the value of
`last-coq-error-location' instead, otherwise parse response buffer and updates
`last-coq-error-location'.

If PARSERESP and CLEAN are non-nil, delete the error location from the response
buffer."
  (proof-with-current-buffer-if-exists proof-script-buffer
    (let ((mtch (coq-get-last-error-location parseresp clean)))
      (when mtch
        (let ((pos (car mtch))
              (lgth (cadr mtch)))
          (goto-char (+ (proof-unprocessed-begin) 1))
          (coq-find-real-start)
          
          ;; utf8 adaptation is made in coq-get-last-error-location above
          (let ((time-offset (if coq-time-commands (length coq--time-prefix) 0)))
            (goto-char (+ (point) pos))
            (span-make-self-removing-span (point) (+ (point) (- lgth time-offset))
                                          'face 'proof-warning-face)))))))

(defun coq-highlight-error-hook ()
  (coq-highlight-error t t))

(add-hook 'proof-shell-handle-error-or-interrupt-hook 'coq-highlight-error-hook t)


;;
;; Scroll response buffer to maximize display of first goal
;;

(defun coq-first-word-before (reg)
  "Get the word before first string matching REG in current buffer."
  (save-excursion
    (goto-char (point-min))
    (re-search-forward reg nil t)
    (goto-char (match-beginning 0))
    (backward-word 1)
    (buffer-substring (point)
                      (progn (forward-word 1) (point)))))

(defun coq-get-from-to-paren (reg)
  "Get the word after first string matching REG in current buffer."
  (save-excursion
    (goto-char (point-min))
    (if (null (re-search-forward reg nil t)) ""
      (goto-char (match-end 0))
      (let ((p (point)))
        (if (null (re-search-forward ")" nil t))
            ""
          (goto-char (match-beginning 0))
          (buffer-substring p (point)))))))



(defun coq-show-first-goal ()
  "Scroll the goal buffer so that the first goal is visible.
First goal is displayed on the bottom of its window, maximizing the
number of hypothesis displayed, without hiding the goal"
  (interactive)
  ;; CPC 2015-12-31: Added the check below: if the command that caused this
  ;; call was silent, we shouldn't touch the goals buffer.  See GitHub issues
  ;; https://github.com/cpitclaudel/company-coq/issues/32 and
  ;; https://github.com/cpitclaudel/company-coq/issues/8.
  (unless (memq 'no-goals-display proof-shell-delayed-output-flags)
    (let ((pg-frame (car (coq-find-threeb-frames)))) ; selecting the good frame
      (with-selected-frame (or pg-frame (window-frame (selected-window)))
        ;; prefer current frame
        (let ((goal-win (or (get-buffer-window proof-goals-buffer) (get-buffer-window proof-goals-buffer t))))
          (if goal-win
              (with-selected-window goal-win
                ;; find snd goal or buffer end, if not found this goes to the
                ;; end of buffer
                (search-forward-regexp "subgoal 2\\|\\'")
                (beginning-of-line)
                ;; find something backward else than a space: bottom of concl
                (ignore-errors (search-backward-regexp "\\S-"))
                (recenter (- 1)) ; put bot of concl at bottom of window
                (beginning-of-line)
                ;; if the top of concl is hidden we may want to show it instead
                ;; of bottom of concl
                (when (and coq-prefer-top-of-conclusion
                         ;; return nil if === is not visible
                         (not (save-excursion (re-search-backward "========" (window-start) t))))
                  (re-search-backward "========" nil t)
                  (recenter 0))
                (beginning-of-line))))))))

(defvar coq-modeline-string2 ")")
(defvar coq-modeline-string1 ")")
(defvar coq-modeline-string0 " Script(")
(defun coq-build-subgoals-string (n s)
  (concat coq-modeline-string0 (int-to-string n)
          "-" s
          (if (> n 1) coq-modeline-string2
            coq-modeline-string1)))

(defun coq-update-minor-mode-alist ()
  "Modify `minor-mode-alist' to display the number of subgoals in the modeline."
  (when (and proof-goals-buffer proof-script-buffer)
    (let ((nbgoals (with-current-buffer proof-goals-buffer
                     (string-to-number (coq-first-word-before "focused\\|subgoal"))))
          (nbunfocused (with-current-buffer proof-goals-buffer
                         (coq-get-from-to-paren "unfocused: "))))
      (with-current-buffer proof-script-buffer
        (let ((toclean (assq 'proof-active-buffer-fake-minor-mode minor-mode-alist)))
          (while toclean ;; clean minor-mode-alist
            (setq minor-mode-alist (remove toclean minor-mode-alist))
            (setq toclean (assq 'proof-active-buffer-fake-minor-mode minor-mode-alist)))
          (setq minor-mode-alist
                (append (list (list 'proof-active-buffer-fake-minor-mode
                                    (coq-build-subgoals-string nbgoals nbunfocused)))
                        minor-mode-alist)))))))





;; This hook must be added before coq-optimise-resp-windows, in order to be evaluated
;; *after* windows resizing.
(add-hook 'proof-shell-handle-delayed-output-hook
	  'coq-show-first-goal)
(add-hook 'proof-shell-handle-delayed-output-hook
	  'coq-update-minor-mode-alist)
(add-hook 'proof-shell-handle-delayed-output-hook
          (lambda ()
            (if (proof-string-match coq-shell-proof-completed-regexp
                                    proof-shell-last-output)
                (proof-clean-buffer proof-goals-buffer))))


(defun is-not-split-vertic (selected-window)
  (<= (- (frame-height) (window-height)) 2))

;; bug fixed in generic ocde, useless now:
;(add-hook 'proof-activate-scripting-hook '(lambda () (when proof-three-window-enable (proof-layout-windows))))

;; *Experimental* auto shrink response buffer in three windows mode. Things get
;; a bit messed up if the response buffer is not at the right place (below
;; goals buffer) TODO: Have this linked to proof-resize-window-tofit in
;; proof-utils.el + customized by the "shrink to fit" menu entry
;;  + have it on by default when in three windows mode.
;; The philosophy is that if goals and response are on the same column, their
;; cumulated size should not change.
(defun coq-optimise-resp-windows ()
  "Resize response buffer to optimal size.
Only when three-buffer-mode is enabled."
  ;; CPC 2015-12-31: Added the check below: if the command that caused this
  ;; call was silent, we shouldn't touch the response buffer.  See GitHub
  ;; issues https://github.com/cpitclaudel/company-coq/issues/32 and
  ;; https://github.com/cpitclaudel/company-coq/issues/8.
  (unless (memq 'no-response-display proof-shell-delayed-output-flags)
    ;; If there is no frame with goql+response then do nothing
    (when (and proof-three-window-enable (coq-find-threeb-frames))
      (let ((pg-frame (car (coq-find-threeb-frames)))) ; selecting one adequat frame
        (with-selected-frame pg-frame
          (when (and (> (frame-height) 10)
                     (get-buffer-window proof-response-buffer))
            (let ((maxhgth
                   (- (+ (with-selected-window (get-buffer-window proof-goals-buffer t) (window-text-height))
                         (with-selected-window (get-buffer-window proof-response-buffer t) (window-text-height)))
                      window-min-height))
                  hgt-resp nline-resp)
              (with-selected-window (get-buffer-window proof-response-buffer)
                (setq hgt-resp (window-text-height))
                (with-current-buffer proof-response-buffer
                  (setq nline-resp ; number of lines we want for response buffer
                        (min maxhgth (max window-min-height ; + 1 for comfort
                                          (+ 1 (count-lines (point-max) (point-min)))))))
                (unless (is-not-split-vertic (selected-window))
                  (shrink-window (- hgt-resp nline-resp)))
                (with-current-buffer proof-response-buffer
                  (goto-char (point-min))
                  (recenter))))))))))

;; TODO: remove/add hook instead? 
(defun coq-optimise-resp-windows-if-option ()
  (when coq-optimise-resp-windows-enable (coq-optimise-resp-windows)))

;; TODO: I would rather have a response-insert-hook thant this two hooks
;; Careful: coq-optimise-resp-windows must be called BEFORE proof-show-first-goal,
;; i.e. added in hook AFTER it.

;; Adapt when displaying a normal message
(add-hook 'proof-shell-handle-delayed-output-hook 'coq-optimise-resp-windows-if-option)
;; Adapt when displaying an error or interrupt
(add-hook 'proof-shell-handle-error-or-interrupt-hook 'coq-optimise-resp-windows-if-option)

;;; DOUBLE HIT ELECTRIC TERMINATOR
;; Trying to have double hit on colon behave like electric terminator. The "."
;; is used for records and modules qualified notatiohns, so electric terminator
;; is not pertinent.

;; TODO: make this a minor mode with something in the modeline, like in
;; pg-user.el for electric-terminator.
;; TODO: Have the same for other commands, but with insertion at all.

(defcustom coq-double-hit-enable nil
  "* Experimental: Whether or not double hit should be enabled in coq mode.
A double hit is performed by pressing twice a key quickly. If
this variable is not nil, then 1) it means that electric
terminator is off and 2) a double hit on the terminator act as
the usual electric terminator. See `proof-electric-terminator'.
"
  :type 'boolean
  :set 'proof-set-value
  :group 'proof-user-options)


(defvar coq-double-hit-hot-key "."
  "The key used for double hit electric terminator. By default this
is the coq terminator \".\" key. For example one can do this:

(setq coq-double-hit-hot-key (kbd \";\"))

to use semi-colon instead (on french keyboard, it is the same key
as \".\" but without shift.")

(defvar coq-double-hit-hot-keybinding nil
  "The keybinding that was erased by double hit terminator enabling.
It will be restored if double hit terminator is toggle off.")

;; We redefine the keybinding when we go in and out of double hit mode, even if
;; in principle coq-terminator-insert is compatible with
;; proof-electric-terminator. This may be overprudent but I suspect that  
(defun coq-double-hit-enable ()
  "Disables electric terminator since double hit is a replacement.
This function is called by `proof-set-value' on `coq-double-hit-enable'."
  (when (and coq-double-hit-enable proof-electric-terminator-enable)
    (proof-electric-terminator-toggle 0))
  ;; this part switch between bindings of coq-double-hit-hot-key: the nominal
  ;; one and coq-terminator-insert
;  (if (not coq-double-hit-enable)
;      (define-key coq-mode-map (kbd coq-double-hit-hot-key) coq-double-hit-hot-keybinding)
;    (setq coq-double-hit-hot-keybinding (key-binding coq-double-hit-hot-key))
;    (define-key coq-mode-map (kbd coq-double-hit-hot-key) 'coq-terminator-insert))
  )



;;(define-key coq-mode-map coq-double-hit-hot-key 'coq-terminator-insert)

(proof-deftoggle coq-double-hit-enable coq-double-hit-toggle)

(defadvice proof-electric-terminator-enable (after coq-unset-double-hit-advice)
  "Disable double hit terminator since electric terminator is a replacement.
This is an advice to pg `proof-electric-terminator-enable' function."
  (when (and coq-double-hit-enable proof-electric-terminator-enable)
    (coq-double-hit-toggle 0)
    (message "Hit M-1 . to enter a real \".\".")))

(ad-activate 'proof-electric-terminator-enable)

(defvar coq-double-hit-delay 0.25
  "The maximum delay between the two hit of a double hit in coq/proofgeneral.")

(defvar coq-double-hit-timer nil
  "the timer used to watch for double hits.")

(defvar coq-double-hit-hot nil
  "The variable telling that a double hit is still possible.")



(defun coq-unset-double-hit-hot ()
  "Disable timer `coq-double-hit-timer' and set it to nil. Shut
off the current double hit if any. This function is supposed to
be called at double hit timeout."
  (when coq-double-hit-timer (cancel-timer coq-double-hit-timer))
  (setq coq-double-hit-hot nil)
  (setq coq-double-hit-timer nil))

(defun coq-colon-self-insert ()
  "Detect a double hit and act as electric terminator if detected.
Starts a timer for a double hit otherwise."
  (interactive)
  (if (and coq-double-hit-hot
           (not (proof-inside-comment (point)))
           (not (proof-inside-string (point))))
      (progn (coq-unset-double-hit-hot)
             (delete-char -1) ; remove previously typed char
             (proof-assert-electric-terminator)); insert the terminator
    (self-insert-command 1)
    (setq coq-double-hit-hot t)
    (setq coq-double-hit-timer
          (run-with-timer coq-double-hit-delay
                          nil 'coq-unset-double-hit-hot))))

(defun coq-terminator-insert (&optional count)
  "A wrapper on `proof-electric-terminator' to accept double hits instead if enabled.
If by accident `proof-electric-terminator-enable' and `coq-double-hit-enable'
are non-nil at the same time, this gives priority to the former."
  (interactive)
  (if (and (not proof-electric-terminator-enable)
           coq-double-hit-enable (null count))
      (coq-colon-self-insert)
    ;; otherwise call this, which checks proof-electric-terminator-enable
    (proof-electric-terminator count)))

(put 'coq-terminator-insert 'delete-selection t)

;; Setting the new mapping for terminator, overrides the following in proof-script:
;; (define-key proof-mode-map (vector (aref proof-terminal-string 0)) 'proof-electric-terminator)

;(define-key proof-mode-map (kbd coq-double-hit-hot-key) 'coq-terminator-insert)
(define-key coq-mode-map (kbd ".") 'coq-terminator-insert)
;(define-key coq-mode-map (kbd ";") 'coq-terminator-insert) ; for french keyboards

;; Activation of ML4PG functionality
(declare-function ml4pg-select-mode "ml4pg") ;; Avoids copilation warnings

(defun coq-activate-ml4pg ()
  (let ((filename (concatenate 'string proof-home-directory "contrib/ML4PG/ml4pg.el")))
    (when (file-exists-p filename) (load-file filename) (ml4pg-select-mode))))

;;;;;;;;;;;;;;

;; This was done in coq-compile-common, but it is actually a good idea even
;; when "compile when require" is off. When switching scripting buffer, let us
;; restart the coq shell process, so that it applies local coqtop options. 
(add-hook 'proof-deactivate-scripting-hook
          'coq-switch-buffer-kill-proof-shell ;; this function is in coq-compile-common
          t)


;; overwriting the default behavior, this is an experiment, *frames* will be
;; deleted only if only displaying associated buffers. If this is OK the
;; function itself will replace the other in generic.
(defun proof-delete-other-frames () (proof-delete-all-associated-windows))

(provide 'coq)



;;   Local Variables: ***
;;   fill-column: 79 ***
;;   indent-tabs-mode: nil ***
;;   coding: utf-8 ***
;;   End: ***

;;; coq.el ends here
