;; coq.el Major mode for Coq proof assistant
;; Copyright (C) 1994 - 1998 LFCS Edinburgh. 
;; Author: Healfdene Goguen
;; Maintainer: Pierre Courtieu <courtieu@lri.fr>

;; $Id$ 

(require 'proof)
(require 'coq-syntax)

;; Configuration

(setq tags-always-exact t) ; Tags is unusable with Coq library otherwise:

(defun coq-library-directory () 
  (let ((c (substring (shell-command-to-string "coqtop -where") 0 -1 )))
    (if (string-match c "not found")
	  "/usr/local/lib/coq"
      c)))

(defcustom coq-tags (concat (coq-library-directory) "/theories/TAGS")
  "the default TAGS table for the Coq library"
  :type 'string
  :group 'coq)

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

(defcustom coq-default-undo-limit 100
  "Maximum number of Undo's possible when doing a proof."
  :type 'number
  :group 'coq)

;; ----- web documentation

(defcustom coq-www-home-page "http://coq.inria.fr/"
  "Coq home page URL."
  :type 'string
  :group 'coq)

;; ----- coq specific menu

;; Pierre: I add Print Check and PrintHint
;; maybe Print and Check should be buttons ?
(defpgdefault menu-entries
  '(["Print..." coq-Print t]
    ["Check..." coq-Check t]
    ["Hints" coq-PrintHint t]
    ["Intros..." coq-Intros t]
    ["Show ith goal..." coq-Show t]
    ["Apply"  coq-Apply t]
    ["Search isos..." coq-SearchIsos t]
    ["Begin Section..." coq-begin-Section t]
    ["End Section" coq-end-Section t]
    ["Compile" coq-Compile t]))


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

(defcustom coq-prog-name "coqtop -emacs"
  "*Name of program to run as Coq."
  :type 'string
  :group 'coq)

;; Command to initialize the Coq Proof Assistant
(defconst coq-shell-init-cmd 
  (format "Set Undo %s." coq-default-undo-limit))

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

(defvar coq-shell-prompt-pattern (concat "^" proof-id " < ")
  "*The prompt pattern for the inferior shell running coq.")

;; FIXME da: this was disabled (set to nil) -- why?
(defvar coq-shell-cd "Cd \"%s\"."
  "*Command of the inferior process to change the directory.") 

(defvar coq-shell-abort-goal-regexp "Current goal aborted"
  "*Regexp indicating that the current goal has been abandoned.")

(defvar coq-shell-proof-completed-regexp "Subtree proved!"
  "*Regular expression indicating that the proof has been completed.")

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

;; ----- outline

(defvar coq-outline-regexp
  (concat "(\\*\\|" (proof-ids-to-regexp 
	   '(
"Tactic" "Axiom" "Parameter" "Parameters" "Variable" "Variables" "Syntax" "Grammar" "Syntactic" "Load" "Require" "Hint" "Hints" "Correctness" "Section" "Chapter" "Goal" "Lemma" "Theorem" "Fact" "Remark" "Record" "Inductive" "Mutual" "Definition" "Fixpoint" "Save" "Qed" "Defined"))))

(defvar coq-outline-heading-end-regexp "\\*\)\n\\|\\.\n")

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

(defconst coq-kill-goal-command "Abort.")
(defconst coq-forget-id-command "Reset %s.")

(defconst coq-undoable-commands-regexp (proof-ids-to-regexp (append coq-tactics coq-keywords-undoable-commands)))

(defconst coq-not-undoable-commands-regexp (proof-ids-to-regexp coq-keywords-not-undoable-commands))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;   Derived modes - they're here 'cos they define keymaps 'n stuff ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(eval-and-compile 
  (define-derived-mode coq-shell-mode proof-shell-mode
    "coq-shell" nil
    (coq-shell-mode-config)))
  
(eval-and-compile 
  (define-derived-mode coq-response-mode proof-response-mode
  "CoqResp" nil
    (coq-response-config)))
 
(eval-and-compile
  (define-derived-mode coq-mode proof-mode
   "coq" nil
   (coq-mode-config)))

(eval-and-compile
  (define-derived-mode coq-goals-mode proof-goals-mode
    "CoqGoals" nil
    (coq-goals-mode-config)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;   Code that's coq specific                                      ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

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

;;
;; FIXME Papageno 05/1999: must take sections in account.
;;
;; Pierre modified the test with proof-string-match, this way new tactics
;; ca be undone (I also added "(*" in not-undoable-commands)
(defun coq-count-undos (span)
  "Count number of undos in a span, return the command needed to undo that far."
  (let ((ct 0) str i)
    (if (and span (prev-span span 'type)
	     (not (eq (span-property (prev-span span 'type) 'type) 'comment))
	     (coq-goal-command-p
	      (span-property (prev-span span 'type) 'cmd)))
	"Restart."
      (while span
	(setq str (span-property span 'cmd))
	(cond ((eq (span-property span 'type) 'vanilla)
	       (if (not (proof-string-match coq-not-undoable-commands-regexp str))
		   (setq ct (+ 1 ct))))
	      ((eq (span-property span 'type) 'pbp)
	       (cond ((not (proof-string-match coq-not-undoable-commands-regexp str))
		      (setq i 0)
		      (while (< i (length str))
			(if (= (aref str i) proof-terminal-char)
			    (setq ct (+ 1 ct)))
			(setq i (+ 1 i))))
		     (t nil))))
	(setq span (next-span span 'type)))
      (concat "Undo " (int-to-string ct) "."))))

(defconst coq-keywords-decl-defn-regexp
  (proof-ids-to-regexp (append coq-keywords-decl coq-keywords-defn))
  "Declaration and definition regexp.")

;; FIXME da: this one function breaks the nice configuration of Proof General:
;; would like to have proof-goal-regexp instead.
;; Unfortunately Coq allows "Definition" and friends to perhaps have a goal, 
;; so it appears more difficult than just a proof-goal-regexp setting.
;; Future improvement may simply to be allow a function value for
;; proof-goal-regexp.

(defun coq-goal-command-p (str)
  "Decide whether argument is a goal or not"
  (and (proof-string-match coq-goal-command-regexp str)
       (not (proof-string-match "Definition.*:=" str))))

;; TODO : add the stuff to handle the "Correctness" command

(defun coq-find-and-forget (span)
  (let (str ans)
    (while (and span (not ans))
      (setq str (span-property span 'cmd))
      (cond

       ((eq (span-property span 'type) 'comment))       

       ((eq (span-property span 'type) 'goalsave)
	;; Note da 6.10.99: in Lego and Isabelle, it's trivial to
	;; forget an unnamed theorem.  Coq really does use the 
	;; identifier "Unnamed_thm", though!  So we don't need
	;; this test:
	;; (unless (eq (span-property span 'name) proof-unnamed-theorem-name)
	(setq ans (format coq-forget-id-command (span-property span 'name))))

       ((proof-string-match (concat "\\`\\(" coq-keywords-decl-defn-regexp
				    "\\)\\s-*\\(" proof-id 
				    ;; da: PG 3.1: I added "." here to try
				    ;; to get undo for Section working.
				    ;; (also changes in coq-syntax)
				    ;; Coq users will have to tell me if it
				    ;; works better now or not?
				    ;; At least I can do C-c C-r in files
				    ;; with Section in them.  But problem
				    ;; with closure still present:
				    ;; Section .. End Section should be
				    ;; atomic!
				    "\\)\\s-*[\\[,:.]") str)
	(setq ans (format coq-forget-id-command (match-string 2 str))))

       ;; If it's not a goal but it contains "Definition" then it's a
       ;; declaration
       ((and (not (coq-goal-command-p str))
	     (proof-string-match
	      (concat "Definition\\s-+\\(" proof-id "\\)\\s-*:") str))
	(setq ans (format coq-forget-id-command (match-string 2 str)))))

      (setq span (next-span span 'type)))

      (or ans proof-no-command)))

(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))
    (setq coq-current-goal (string-to-int (match-string 1))))
   ((looking-at proof-shell-assumption-regexp)
    (cons 'hyp (match-string 1)))
   (t nil)))

;;
;; This code is broken
;; 
; (defun coq-lift-global (glob-span)
;   "This function lifts local lemmas from inside goals out to top level."
;   (let (start (next (span-at 1 'type)) str (goal-p nil))
;     (while (and next (and (not (eq next glob-span)) (not goal-p)))
;       (if (and (eq (span-property next 'type) 'vanilla)
; 	       (funcall proof-goal-command-p (span-property next 'cmd)))
; 	  (setq goal-p t)
; 	(setq next (next-span next 'type))))
    
;     (if (and next (not (eq next glob-span)))
; 	(progn
; 	  (proof-unlock-locked)
; 	  (setq str (buffer-substring (span-start glob-span)
; 				      (span-end glob-span)))
; 	  (delete-region (span-start glob-span) (span-end glob-span))
; 	  (goto-char (span-start next))
; 	  (setq start (point))
; 	  (insert str "\n")
; 	  (set-span-endpoints glob-span start (point))
; 	  (set-span-start next (point))
; 	  (proof-lock-unlocked)))))

(defun coq-state-preserving-p (cmd)
  (not (proof-string-match coq-undoable-commands-regexp cmd)))

(defun coq-global-p (cmd)
  (or (proof-string-match coq-keywords-decl-defn-regexp cmd)
      (and (proof-string-match
	    (concat "Definition\\s-+\\(" coq-id "\\)\\s-*:") cmd)
	   (proof-string-match ":=" cmd))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;   Commands specific to coq                                       ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defun coq-SearchIsos ()
  "Search a term whose type is isomorphic to given type
This is specific to coq-mode."
  (interactive)
  (let (cmd)
    (proof-shell-ready-prover) 
    (setq cmd (read-string "SearchIsos: " nil 'proof-minibuffer-history))
    (proof-shell-invisible-command
     (format "SearchIsos %s." cmd))))


(defun coq-Print ()
  "Ask for an ident and print the corresponding term"
  (interactive)
  (let (cmd)
    (proof-shell-ready-prover) 
    (setq cmd (read-string "Print: " nil 'proof-minibuffer-history))
    (proof-shell-invisible-command
     (format "Print %s." cmd))))

(defun coq-Check ()
  "Ask for a term and print its type"
  (interactive)
  (let (cmd)
    (proof-shell-ready-prover) 
    (setq cmd (read-string "Check: " nil 'proof-minibuffer-history))
    (proof-shell-invisible-command
     (format "Check %s." cmd))))

(defun coq-Show ()
  "Ask for a number i and show the ith goal"
  (interactive)
  (let (cmd)
    (proof-shell-ready-prover) 
    (setq cmd (read-string "Show Goal number: " nil 'proof-minibuffer-history))
    (proof-shell-invisible-command
     (format "Show %s." cmd))))

(defun coq-PrintHint ()
  "Print all hints applicable to the current goal"
  (interactive)
  (proof-shell-invisible-command "Print Hint."))


(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-string
		(progn (beginning-of-line) (forward-word 1) (point)) 
		(progn (end-of-line) (point)))))))
      (insert (concat "End" section)))))

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

(proof-defshortcut coq-Intros        "Intros "  [(control ?i)])
(proof-defshortcut coq-Apply         "Apply "   [(control ?a)])
(proof-defshortcut coq-begin-Section "Section " [(control ?s)])

(define-key coq-keymap [(control ?e)] 'coq-end-Section)
(define-key coq-keymap [(control ?m)] 'coq-Compile)
(define-key coq-keymap [(control ?o)] 'coq-SearchIsos)
(define-key coq-keymap [(control ?p)] 'coq-Print)
(define-key coq-keymap [(control ?c)] 'coq-Check)
(define-key coq-keymap [(control ?h)] 'coq-PrintHint)


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;   Indentation                                                    ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; FIXME mmw: code disabled; Is the new indentation scheme general
;; enough to handle Coq as well?

;;; "Case" is represented by 'c' on the stack, and
;;; "CoInductive" is represented by 'C'.
;(defun coq-stack-to-indent (stack)
;  (cond
;   ((null stack) 0)
;   ((null (car (car stack)))
;    (nth 1 (car stack)))
;   (t (let ((col (save-excursion
;		   (goto-char (nth 1 (car stack)))
;		   (current-column))))
;	(cond
;	 ((eq (car (car stack)) ?c)
;	  (save-excursion (move-to-column (current-indentation))
;			  (cond 
;			   ((eq (char-after (point)) ?|) (+ col 3))
;			   ((proof-looking-at "end") col)
;			   (t (+ col 5)))))	  
;	 ((or (eq (car (car stack)) ?I) (eq (car (car stack)) ?C))
;	  (+ col (if (eq ?| (save-excursion 
;			      (move-to-column (current-indentation))
;			      (char-after (point)))) 2 4)))
;	 (t (1+ col)))))))
;
;(defun coq-parse-indent (c stack)
;  (cond
;   ((eq c ?C)
;    (cond ((proof-looking-at "Case")
;	   (cons (list ?c (point)) stack))
;	  ((proof-looking-at "CoInductive")
;	   (forward-char (length "CoInductive"))
;	   (cons (list c (- (point) (length "CoInductive"))) stack))
;	  (t stack)))
;   ((and (eq c ?e) (proof-looking-at "end") (eq (car (car stack)) ?c))
;    (cdr stack))
;
;   ((and (eq c ?I) (proof-looking-at "Inductive"))
;    (forward-char (length "Inductive"))
;    (cons (list c (- (point) (length "Inductive"))) stack))
;
;   ((and (eq c ?.) (or (eq (car (car stack)) ?I) (eq (car (car stack)) ?C)))
;    (cdr stack))
;
;   (t stack)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;    To guess the command line options   ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defun coq-guess-command-line (filename)
  "Guess the right command line options to compile FILENAME using `make -n'"
  (let ((dir (file-name-directory filename)))
    (if (file-exists-p (concat dir "Makefile"))
	(let* 
	    ((compiled-file (concat (substring 
				     filename 0 
				     (string-match ".v$" filename)) ".vo"))
	     (command (shell-command-to-string 
		       (concat  "cd " dir ";"
				"gmake -n -W " filename " " compiled-file
				"| sed s/coqc/coqtop/"))))
	  (concat 
	   (substring command 0 (string-match " [^ ]*$" command))
	   " -emacs"))
      coq-prog-name)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;   Coq shell startup and exit hooks                               ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defun coq-pre-shell-start ()
  (setq proof-prog-name coq-prog-name)
  (setq proof-mode-for-shell    'coq-shell-mode)
  (setq proof-mode-for-goals    'coq-goals-mode)
  (setq proof-mode-for-response 'coq-response-mode)
)

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

(defun coq-mode-config ()

  (setq proof-terminal-char ?\.)
  (setq proof-comment-start "(*")
  (setq proof-comment-end "*)")
  (setq proof-unnamed-theorem-name "Unnamed_thm") ; Coq's default name

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

  (setq proof-mode-for-script 'coq-mode)

  (setq proof-guess-command-line 'coq-guess-command-line)

  ;; 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"
	proof-kill-goal-command coq-kill-goal-command)

  (setq proof-goal-command-p 'coq-goal-command-p
	proof-count-undos-fn 'coq-count-undos
	proof-find-and-forget-fn 'coq-find-and-forget
        proof-goal-hyp-fn 'coq-goal-hyp
	proof-state-preserving-p 'coq-state-preserving-p
	proof-global-p 'coq-global-p)

  (setq proof-save-command-regexp coq-save-command-regexp
	proof-save-with-hole-regexp coq-save-with-hole-regexp
	proof-goal-with-hole-regexp coq-goal-with-hole-regexp)
  
  (setq	
   proof-indent-close-offset -1
   proof-indent-any-regexp
   (proof-regexp-alt (proof-ids-to-regexp
		      (append (list "Cases" "end") coq-keywords)) "\\s(" "\\s)")
   proof-indent-enclose-regexp "|"
   proof-indent-open-regexp
   (proof-regexp-alt (proof-ids-to-regexp '("Cases")) "\\s(")
   proof-indent-close-regexp
   (proof-regexp-alt (proof-ids-to-regexp '("end")) "\\s)"))
  
  (setq proof-auto-multiple-files t)	; until Coq has real support

  (setq proof-shell-start-silent-cmd "Begin Silent."
	proof-shell-stop-silent-cmd  "End Silent.")

  (coq-init-syntax-table)

;; font-lock

  (setq font-lock-keywords coq-font-lock-keywords-1)

  (setq proof-font-lock-zap-commas t)	; enable the painful hack
  
  (proof-config-done)

;; outline
  
  (make-local-variable 'outline-regexp)
  (setq outline-regexp coq-outline-regexp)

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

;; tags
  (and (boundp 'tag-table-alist)
       (setq tag-table-alist
	     (append '(("\\.v$" . coq-tags)
		       ("coq"  . coq-tags))
		     tag-table-alist)))

  (setq blink-matching-paren-dont-ignore-comments t)

;; hooks and callbacks
  
  (add-hook 'proof-pre-shell-start-hook 'coq-pre-shell-start nil t))
  


(defun coq-shell-mode-config ()
  (setq 
   proof-shell-prompt-pattern coq-shell-prompt-pattern
   proof-shell-cd-cmd coq-shell-cd
   proof-shell-filename-escapes '(("\\\\" . "\\\\") ("\""   . "\\\""))
   proof-shell-abort-goal-regexp coq-shell-abort-goal-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
   proof-shell-first-special-char ?\360
   proof-shell-wakeup-char ?\371 ; done: prompt
   ;; The next three represent path annotation information
   proof-shell-start-char ?\372 ; not done
   proof-shell-end-char ?\373 ; not done
   proof-shell-field-char ?\374 ; not done
   proof-shell-goal-char ?\375 ; done
   proof-shell-eager-annotation-start "\376" ; done
   proof-shell-eager-annotation-start-length 1
   proof-shell-eager-annotation-end "\377" ; done
   proof-shell-annotated-prompt-regexp
   (concat proof-shell-prompt-pattern
	   (char-to-string proof-shell-wakeup-char)) ; done
   proof-shell-result-start "\372 Pbp result \373"
   proof-shell-result-end "\372 End Pbp result \373"
   proof-shell-start-goals-regexp "[0-9]+ subgoals?"
   proof-shell-end-goals-regexp proof-shell-annotated-prompt-regexp
   proof-shell-init-cmd  ; (concat
			 coq-shell-init-cmd
	                 ; Coq has no global settings?
			 ; (proof-assistant-settings-cmd))
   proof-shell-restart-cmd coq-shell-restart-cmd
   proof-analyse-using-stack t
   ;;	proof-lift-global 'coq-lift-global
   )
  
  (coq-init-syntax-table)
  (setq font-lock-keywords coq-font-lock-keywords-1)

  (proof-shell-config-done))

(defun coq-goals-mode-config ()
  (setq pbp-change-goal "Show %s.")
  (setq pbp-error-regexp coq-error-regexp)
  (coq-init-syntax-table)
  (setq font-lock-keywords coq-font-lock-keywords-1)
  (proof-goals-config-done))

(defun coq-response-config ()
   (coq-init-syntax-table)
   (setq font-lock-keywords coq-font-lock-keywords-1)
   (proof-response-config-done))


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Flags and other settings for Coq.
;;

;; da: neither of these work very well.
;; I think "time" must just be for special search isos top level,
;; and "Focus" on works during a proof, so sending the setting
;; at the start of a session is wrong.

;(defpacustom time-search-isos  nil
;  "Whether to display timing of SearchIsos in Coq."
;  :type 'boolean
;  :setting ("Time." . "Untime."))

(defpacustom print-only-first-subgoal  nil
  "Whether to just print the first subgoal in Coq."
  :type 'boolean
  :setting ("Focus." . "Unfocus."))

(provide 'coq)