;;; ada-xref.el --- for lookup and completion in Ada mode

;; Copyright (C) 1994, 95, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.

;; Author: Markus Heritsch <Markus.Heritsch@studbox.uni-stuttgart.de>
;;      Rolf Ebert <ebert@inf.enst.fr>
;;      Emmanuel Briot <briot@gnat.com>
;; Maintainer: Emmanuel Briot <briot@gnat.com>
;; Ada Core Technologies's version:   $Revision: 1.8 $
;; Keywords: languages ada xref

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:
;;; This Package provides a set of functions to use the output of the
;;; cross reference capabilities of the GNAT Ada compiler
;;; for lookup and completion in Ada mode.
;;;
;;; The functions provided are the following ones :
;;;    - `ada-complete-identifier': completes the current identifier as much as
;;;      possible, depending of the known identifier in the unit
;;;    - `ada-point-and-xref': moves the mouse pointer and shows the declaration
;;;      of the selected identifier (either in the same buffer or in another
;;;      buffer
;;;    - `ada-goto-declaration': shows the declaration of the selected
;;;      identifier (the one under the cursor), either in the same buffer or in
;;;      another buffer
;;;    - `ada-goto-declaration-other-frame': same as previous, but opens a new
;;      frame to show the declaration
;;;    - `ada-compile-application': recompile your whole application, provided
;;;      that a project file exists in your directory
;;;    - `ada-run-application': run your application directly from Emacs
;;;    - `ada-reread-prj-file': force Emacs to read your project file again.
;;;      Otherwise, this file is only read the first time Emacs needs some
;;;      informations, which are then kept in memory
;;;    - `ada-change-prj': change the prj file associated with a buffer
;;;    - `ada-change-default-prj': change the default project file used for
;;;      every new buffer
;;;
;;; If a file *.`adp' exists in the ada-file directory, then it is
;;; read for configuration informations. It is read only the first
;;; time a cross-reference is asked for, and is not read later.

;;; You need Emacs >= 20.2 to run this package

;;; Code:

;; ----- Requirements -----------------------------------------------------

(require 'compile)
(require 'comint)

;; ------ Use variables
(defcustom ada-xref-other-buffer t
  "*If nil, always display the cross-references in the same buffer.
Otherwise create either a new buffer or a new frame."
  :type 'boolean :group 'ada)

(defcustom ada-xref-create-ali t
  "*If non-nil, run gcc whenever the cross-references are not up-to-date.
If nil, the cross-reference mode will never run gcc."
  :type 'boolean :group 'ada)

(defcustom ada-xref-confirm-compile nil
  "*If non-nil, always ask for user confirmation before compiling or running
the application."
  :type 'boolean :group 'ada)

(defcustom ada-krunch-args "0"
  "*Maximum number of characters for filenames created by gnatkr.
Set to 0, if you don't use crunched filenames. This should be a string."
  :type 'string :group 'ada)

(defcustom ada-prj-default-comp-opt "-gnatq"
  "Default compilation options."
  :type 'string :group 'ada)

(defcustom ada-prj-default-bind-opt ""
  "Default binder options."
  :type 'string :group 'ada)

(defcustom ada-prj-default-link-opt ""
  "Default linker options."
  :type 'string :group 'ada)

(defcustom ada-prj-default-gnatmake-opt "-g"
  "Default options for gnatmake."
  :type 'string :group 'ada)

(defcustom ada-prj-default-comp-cmd
  "${cross_prefix}gcc -c ${comp_opt}"
  "*Default command to be used to compile a single file.
Emacs will add the filename at the end of this command. This is the same
syntax as in the project file."
  :type 'string :group 'ada)

(defcustom ada-prj-default-debugger "${cross_prefix}gdb"
  "*Default name of the debugger. We recommend either `gdb',
`gdb --emacs_gdbtk' or `ddd --tty -fullname'."
  :type 'string :group 'ada)

(defcustom ada-prj-default-make-cmd
  (concat "${cross_prefix}gnatmake -o ${main} ${main_unit} ${gnatmake_opt} "
          "-cargs ${comp_opt} -bargs ${bind_opt} -largs ${link_opt}")
  "*Default command to be used to compile the application.
This is the same syntax as in the project file."
  :type 'string :group 'ada)

(defcustom ada-prj-default-project-file ""
  "*Name of the project file to use for every Ada file.
Emacs will not try to use the standard algorithm to find the project file if
this string is not empty."
  :type '(file :must-match t) :group 'ada)

(defcustom ada-gnatstub-opts "-q -I${src_dir}"
  "*List of the options to pass to gnatsub to generate the body of a package.
This has the same syntax as in the project file (with variable substitution)."
  :type 'string :group 'ada)

(defcustom ada-always-ask-project nil
  "*If nil, use default values when no project file was found.
Otherwise, ask the user for the name of the project file to use."
  :type 'boolean :group 'ada)

;; ------- Nothing to be modified by the user below this
(defvar ada-last-prj-file ""
  "Name of the last project file entered by the user.")

(defvar ada-check-switch "-gnats"
  "Switch added to the command line to check the current file.")

(defvar ada-project-file-extension ".adp"
  "The extension used for project files.")

(defconst is-windows (memq system-type (quote (windows-nt)))
  "True if we are running on windows NT or windows 95.")

(defvar ada-xref-runtime-library-specs-path '()
  "Directories where the specs for the standard library is found.
This is used for cross-references.")

(defvar ada-xref-runtime-library-ali-path '()
  "Directories where the ali for the standard library is found.
This is used for cross-references.")

(defvar ada-xref-pos-ring '()
  "List of positions selected by the cross-references functions.
Used to go back to these positions.")

(defconst ada-xref-pos-ring-max 16
  "Number of positions kept in the list ada-xref-pos-ring.")

(defvar ada-operator-re
  "\\+\\|-\\|/\\|\\*\\*\\|\\*\\|=\\|&\\|abs\\|mod\\|rem\\|and\\|not\\|or\\|xor\\|<=\\|<\\|>=\\|>"
  "Regexp to match for operators.")

(defvar ada-xref-default-prj-file nil
  "Name of the default prj file, per directory.
Every directory is potentially associated with a default project file.
If it is nil, then the first prj file loaded will be the default for this
Emacs session.")


(defvar ada-xref-project-files '()
  "Associative list of project files.
It has the following format:
\((project_name . value) (project_name . value) ...)
As always, the values of the project file are defined through properties.")

(defvar ada-prj-prj-file nil
  "Buffer local variable that specifies the name of the project file.
Getting the project is done by looking up the key in ada-pxref-project-file.")

(defun my-local-variable-if-set-p (variable &optional buffer)
  "Returns t if VARIABLE is local in BUFFER and is non-nil."
  (and (local-variable-p variable buffer)
       (save-excursion
         (set-buffer buffer)
         (symbol-value variable))))

(defun ada-initialize-runtime-library ()
  "Initializes the variables for the runtime library location."
  (save-excursion
    (set 'ada-xref-runtime-library-specs-path '())
    (set 'ada-xref-runtime-library-ali-path '())
    (set-buffer (get-buffer-create "*gnatls*"))
    (widen)
    (erase-buffer)
    ;;  Catch any error in the following form (i.e gnatls was not found)
    (condition-case nil
	;;  Even if we get an error, delete the *gnatls* buffer
	(unwind-protect
	    (progn
	      (call-process "gnatls" nil t nil "-v")
	      (goto-char (point-min))

	      ;;  Source path
	      
	      (search-forward "Source Search Path:")
	      (forward-line 1)
	      (while (not (looking-at "^$"))
		(back-to-indentation)
		(unless (looking-at "<Current_Directory>")
		  (add-to-list 'ada-xref-runtime-library-specs-path
			       (buffer-substring-no-properties
				(point)
				  (save-excursion (end-of-line) (point)))))
		(forward-line 1))

	      ;;  Object path
	      
	      (search-forward "Object Search Path:")
	      (forward-line 1)
	      (while (not (looking-at "^$"))
		(back-to-indentation)
		(unless (looking-at "<Current_Directory>")
		  (add-to-list 'ada-xref-runtime-library-ali-path
			       (buffer-substring-no-properties
				(point)
				(save-excursion (end-of-line) (point)))))
		(forward-line 1))
	      )
	    (kill-buffer nil))
      (error nil))
    (set 'ada-xref-runtime-library-specs-path
	 (reverse ada-xref-runtime-library-specs-path))
    (set 'ada-xref-runtime-library-ali-path
	 (reverse ada-xref-runtime-library-ali-path))
    ))


(defun ada-treat-cmd-string (cmd-string)
  "Replace meta-sequences like ${...} in CMD-STRING with the appropriate value.
The project file must have been loaded first.
As a special case, ${current} is replaced with the name of the currently
edited file, minus extension but with directory."

  (while (string-match "\\(-[^-\$IO]*[IO]\\)?\${\\([^}]+\\)}" cmd-string)
    (let (value)
      (if (string= (match-string 2 cmd-string) "current")
	  (set 'value (file-name-sans-extension (buffer-file-name)))
	(save-match-data
	  (set 'value (ada-xref-get-project-field
		       (intern (match-string 2 cmd-string))))))
      (cond
       ((null value)
	(set 'cmd-string (replace-match "" t t cmd-string)))
       ((stringp value)
	(set 'cmd-string (replace-match value t t cmd-string)))
       ((listp value)
	(let ((prefix (match-string 1 cmd-string)))
	  (set 'cmd-string (replace-match
			    (mapconcat (lambda(x) (concat prefix x)) value " ")
			    t t cmd-string)))))
      ))
  cmd-string)

(defun ada-xref-set-default-prj-values (symbol ada-buffer)
  "Reset the properties in SYMBOL to the default values for ADA-BUFFER."

  (let ((file      (buffer-file-name ada-buffer))
	plist)
    (save-excursion
      (set-buffer ada-buffer)
      
      (set 'plist
	   ;;  Try hard to find a default value for filename, so that the user
	   ;;  can edit his project file even if the current buffer is not an
	   ;;  Ada file or not even associated with a file
	   (list 'filename        (cond
				   (file
				    (ada-prj-get-prj-dir file))
				   (ada-prj-prj-file
				    ada-prj-prj-file)
				   (ada-xref-default-prj-file
				    ada-xref-default-prj-file)
				   (t
				    (error (concat "Not editing an Ada file,"
						   "and no default project "
						   "file specified!"))))
		 'build_dir       (file-name-as-directory (expand-file-name "."))
		 'src_dir         (list ".")
		 'obj_dir         (list ".")
		 'casing          (if (listp ada-case-exception-file)
				      ada-case-exception-file
				    (list ada-case-exception-file))
		 'comp_opt        ada-prj-default-comp-opt
		 'bind_opt        ada-prj-default-bind-opt
		 'link_opt        ada-prj-default-link-opt
		 'gnatmake_opt    ada-prj-default-gnatmake-opt
		 'main            (if file
				      (file-name-sans-extension file)
				    "")
		 'main_unit       (if file
				      (file-name-nondirectory
				       (file-name-sans-extension file))
				    "")
		 'cross_prefix    ""
		 'remote_machine  ""
		 'comp_cmd        (concat "cd ${build_dir} && "
					  ada-prj-default-comp-cmd)
		 'check_cmd       (concat ada-prj-default-comp-cmd " "
					  ada-check-switch)
		 'make_cmd        (concat "cd ${build_dir} && "
					  ada-prj-default-make-cmd)
		 'run_cmd         (concat "cd ${build_dir} && ${main}"
					  (if is-windows ".exe"))
		 'debug_cmd       (concat ada-prj-default-debugger
					  (if is-windows " ${main}.exe"
					    " ${main}"))))
      )
    (set symbol plist)))
  
(defun ada-xref-get-project-field (field)
  "Extract the value of FIELD from the project file of the current buffer.
The project file must have been loaded first.
A default value is returned if the file was not found."

  (let ((file-name ada-prj-prj-file)
	file value)

    ;;  If a default project file was set, use it if no other project
    ;;  file was specified for the buffer
    (if (and (not file-name) 
	     ada-prj-default-project-file
	     (not (string= ada-prj-default-project-file "")))
	(set 'file-name ada-prj-default-project-file))
    
    (set 'file (assoc file-name ada-xref-project-files))
	
    ;;  If the file was not found, use the default values
    (if file
	;;  Get the value from the file
	(set 'value (plist-get (cdr file) field))

      ;; Create a default nil file that contains the default values
      (ada-xref-set-default-prj-values 'value (current-buffer))
      (add-to-list 'ada-xref-project-files (cons nil value))
      (set 'value (plist-get value field))
      )
    (if (stringp value)
	(ada-treat-cmd-string value)
      value))
  )

;; ----- Keybindings ------------------------------------------------------

(defun ada-add-keymap ()
  "Add new key bindings when using `ada-xrel.el'."
  (interactive)
  (if ada-xemacs
      (progn
        (define-key ada-mode-map '(shift button3) 'ada-point-and-xref)
        (define-key ada-mode-map '(control tab) 'ada-complete-identifier))
    (define-key ada-mode-map [C-tab] 'ada-complete-identifier)
    (define-key ada-mode-map [S-mouse-3] 'ada-point-and-xref))

  (define-key ada-mode-map "\C-co"    'ff-find-other-file)
  (define-key ada-mode-map "\C-c5\C-d" 'ada-goto-declaration-other-frame)
  (define-key ada-mode-map "\C-c\C-d" 'ada-goto-declaration)
  (define-key ada-mode-map "\C-c\C-s" 'ada-xref-goto-previous-reference)
  (define-key ada-mode-map "\C-c\C-x" 'ada-reread-prj-file)
  (define-key ada-mode-map "\C-c\C-c" 'ada-compile-application)
  (define-key ada-mode-map "\C-cb"  'ada-buffer-list)
  (define-key ada-mode-map "\C-cc"  'ada-change-prj)
  (define-key ada-mode-map "\C-cd"  'ada-change-default-prj)
  (define-key ada-mode-map "\C-cg"  'ada-gdb-application)
  (define-key ada-mode-map "\C-cr"  'ada-run-application)
  (define-key ada-mode-map "\C-c\C-o" 'ada-goto-parent)
  (define-key ada-mode-map "\C-c\C-r" 'ada-find-references)
  (define-key ada-mode-map "\C-c\C-v" 'ada-check-current)
  )

;; ----- Menus --------------------------------------------------------------
(defun ada-add-ada-menu ()
  "Add some items to the standard Ada mode menu.
The items are added to the menu called NAME, which should be the same
name as was passed to `ada-create-menu'."
  (interactive)
  (if ada-xemacs
      (let* ((menu-list '("Ada"))
	     (goto-menu '("Ada" "Goto"))
	     (edit-menu '("Ada" "Edit"))
	     (help-menu '("Ada" "Help"))
	     (options-menu (list "Ada" "Options")))
	(funcall (symbol-function 'add-menu-button)
		 menu-list ["Check file" ada-check-current
			    (string= mode-name "Ada")] "Goto")
	(funcall (symbol-function 'add-menu-button)
		 menu-list ["Compile file" ada-compile-current
			    (string= mode-name "Ada")] "Goto")
	(funcall (symbol-function 'add-menu-button)
		 menu-list ["Build" ada-compile-application t] "Goto")
	(funcall (symbol-function 'add-menu-button)
		 menu-list ["Run" ada-run-application t] "Goto")
	(funcall (symbol-function 'add-menu-button)
		 menu-list ["Debug" ada-gdb-application t] "Goto")
	(funcall (symbol-function 'add-menu-button)
		 menu-list ["--" nil t] "Goto")
	(funcall (symbol-function 'add-submenu)
		 menu-list '("Project"
			     ["Associate"   ada-change-prj t]
			     ["Set Default..." ada-set-default-project-file t]
			     ["List" ada-buffer-list t])
		 "Goto")
	(funcall (symbol-function 'add-menu-button)
		 goto-menu ["Goto Parent Unit" ada-goto-parent t]
		 "Next compilation error")
	(funcall (symbol-function 'add-menu-button)
		 goto-menu ["Goto References to any entity"
			    ada-find-any-references t]
		 "Next compilation error")
	(funcall (symbol-function 'add-menu-button)
		 goto-menu ["List References" ada-find-references t]
		 "Next compilation error")
	(funcall (symbol-function 'add-menu-button)
		 goto-menu ["Goto Declaration Other Frame"
			    ada-goto-declaration-other-frame t]
		 "Next compilation error")
	(funcall (symbol-function 'add-menu-button)
		 goto-menu ["Goto Declaration/Body"
			    ada-goto-declaration t]
		 "Next compilation error")
	(funcall (symbol-function 'add-menu-button)
		 goto-menu ["Goto Previous Reference"
			    ada-xref-goto-previous-reference t]
		 "Next compilation error")
	(funcall (symbol-function 'add-menu-button)
		 goto-menu ["--" nil t] "Next compilation error")
	(funcall (symbol-function 'add-menu-button)
		 edit-menu ["Complete Identifier"
			    ada-complete-identifier t]
		 "Indent Line")
	(funcall (symbol-function 'add-menu-button)
		 edit-menu ["--------" nil t] "Indent Line")
	(funcall (symbol-function 'add-menu-button)
		 help-menu ["Gnat User Guide" (info "gnat_ug")])
	(funcall (symbol-function 'add-menu-button)
		 help-menu ["Gnat Reference Manual" (info "gnat_rm")])
	(funcall (symbol-function 'add-menu-button)
		 help-menu ["Gcc Documentation" (info "gcc")])
	(funcall (symbol-function 'add-menu-button)
		 help-menu ["Gdb Documentation" (info "gdb")])
	(funcall (symbol-function 'add-menu-button)
		 help-menu ["Ada95 Reference Manual" (info "arm95")])
	(funcall (symbol-function 'add-menu-button)
		 options-menu
		 ["Show Cross-References in Other Buffer"
		  (setq ada-xref-other-buffer
			(not ada-xref-other-buffer))
		  :style toggle :selected ada-xref-other-buffer])
	(funcall (symbol-function 'add-menu-button)
		 options-menu
		 ["Automatically Recompile for Cross-References"
		  (setq ada-xref-create-ali (not ada-xref-create-ali))
		  :style toggle :selected ada-xref-create-ali])
	(funcall (symbol-function 'add-menu-button)
		 options-menu
		 ["Confirm Commands"
		  (setq ada-xref-confirm-compile
			(not ada-xref-confirm-compile))
		  :style toggle :selected ada-xref-confirm-compile])
	)
    
    ;; for Emacs
    (let* ((menu         (lookup-key ada-mode-map [menu-bar Ada]))
	   (edit-menu    (lookup-key ada-mode-map [menu-bar Ada Edit]))
	   (help-menu    (lookup-key ada-mode-map [menu-bar Ada Help]))
	   (goto-menu    (lookup-key ada-mode-map [menu-bar Ada Goto]))
	   (options-menu (lookup-key ada-mode-map [menu-bar Ada Options])))

      (define-key-after menu [Check] '("Check file" . ada-check-current)
	'Customize)
      (define-key-after menu [Compile] '("Compile file" . ada-compile-current)
        'Check)
      (define-key-after menu [Build]   '("Build" . ada-compile-application)
	'Compile)
      (define-key-after menu [Run]     '("Run"   . ada-run-application) 'Build)
      (define-key-after menu [Debug]   '("Debug" . ada-gdb-application) 'Run)
      (define-key-after menu [rem]     '("--"    . nil) 'Debug)
      (define-key-after menu [Project]
	(cons "Project"
	      (funcall (symbol-function 'easy-menu-create-menu)
		       "Project"
		       '(["Associate..."   ada-change-prj t
			  :included (string= mode-name "Ada")]
			 ["Set Default..." ada-set-default-project-file t]
			 ["List"        ada-buffer-list t])))
	'rem)

      (define-key help-menu [Gnat_ug]
        '("Gnat User Guide" . (lambda() (interactive) (info "gnat_ug"))))
      (define-key help-menu [Gnat_rm]
        '("Gnat Reference Manual" . (lambda() (interactive) (info "gnat_rm"))))
      (define-key help-menu [Gcc]
        '("Gcc Documentation" . (lambda() (interactive) (info "gcc"))))
      (define-key help-menu [gdb]
        '("Gdb Documentation" . (lambda() (interactive) (info "gdb"))))
      (define-key help-menu [gdb]
        '("Ada95 Reference Manual" . (lambda() (interactive) (info "arm95"))))

      (define-key goto-menu [rem]    '("----" . nil))
      (define-key goto-menu [Parent] '("Goto Parent Unit"
				       . ada-goto-parent))
      (define-key goto-menu [References-any]
	'("Goto References to any entity" . ada-find-any-references))
      (define-key goto-menu [References]
	'("List References" . ada-find-references))
      (define-key goto-menu [Prev]
	'("Goto Previous Reference" . ada-xref-goto-previous-reference))
      (define-key goto-menu [Decl-other]
	'("Goto Declaration Other Frame" . ada-goto-declaration-other-frame))
      (define-key goto-menu [Decl]
	'("Goto Declaration/Body" . ada-goto-declaration))
      
      (define-key edit-menu [rem] '("----" . nil))
      (define-key edit-menu [Complete] '("Complete Identifier"
					 . ada-complete-identifier))

      (define-key-after options-menu [xrefrecompile]
	'(menu-item "Automatically Recompile for Cross-References"
		    (lambda()(interactive)
		      (setq ada-xref-create-ali (not ada-xref-create-ali)))
		    :button (:toggle . ada-xref-create-ali)) t)
      (define-key-after options-menu [xrefconfirm]
	'(menu-item "Confirm Commands"
		   (lambda()(interactive)
		     (setq ada-xref-confirm-compile
			   (not ada-xref-confirm-compile)))
		   :button (:toggle . ada-xref-confirm-compile)) t)
      (define-key-after options-menu [xrefother]
	'(menu-item "Show Cross-References in Other Buffer"
		   (lambda()(interactive)
		     (setq ada-xref-other-buffer (not ada-xref-other-buffer)))
		   :button (:toggle . ada-xref-other-buffer)) t)
      )
    )
  )

;; ----- Utilities -------------------------------------------------

(defun ada-require-project-file ()
  "If no project file is assigned to this buffer, load one."
  (if (not (my-local-variable-if-set-p 'ada-prj-prj-file (current-buffer)))
      (ada-reread-prj-file)))
      
(defun ada-xref-push-pos (filename position)
  "Push (FILENAME, POSITION) on the position ring for cross-references."
  (setq ada-xref-pos-ring (cons (list position filename) ada-xref-pos-ring))
  (if (> (length ada-xref-pos-ring) ada-xref-pos-ring-max)
      (setcdr (nthcdr (1- ada-xref-pos-ring-max) ada-xref-pos-ring) nil)))

(defun ada-xref-goto-previous-reference ()
  "Go to the previous cross-reference we were on."
  (interactive)
  (if ada-xref-pos-ring
      (let ((pos (car ada-xref-pos-ring)))
	(setq ada-xref-pos-ring (cdr ada-xref-pos-ring))
	(find-file (car (cdr pos)))
	(goto-char (car pos)))))

(defun ada-convert-file-name (name)
  "Converts from NAME to a name that can be used by the compilation commands.
This is overriden on VMS to convert from VMS filenames to Unix filenames."
  name)

(defun ada-set-default-project-file (name)
  "Set the file whose name is NAME as the default project file."
  (interactive "fProject file:")

  ;;  All the directories should use this file as the default from now on,
  ;;  even if they were already associated with a file.
  (set 'ada-xref-default-prj-file nil)

  (set 'ada-prj-default-project-file name)

  ;; Make sure that all the buffers see the new project file, even if they
  ;; are not Ada buffers (for instance if we want to display the current
  ;; project file in the frame title).
  (setq-default ada-prj-prj-file name)
  
  (ada-reread-prj-file name)
  )

;; ------ Handling the project file -----------------------------

(defun ada-prj-find-prj-file (&optional no-user-question)
  "Find the prj file associated with the current buffer.
If NO-USER-QUESTION is non-nil, use a default file if not project file was
found, and do not ask the user.
If the buffer is not an Ada buffer, associate it with the default project
file. If none is set, return nil."

  (let (selected)

    ;;  If we don't have an ada buffer, or the current buffer is not
    ;;  a real file (for instance an emerge buffer)
    
    (if (or (not (string= mode-name "Ada"))
	    (not (buffer-file-name)))

	;;  1st case: not an Ada buffer
	(if (and ada-prj-default-project-file
		 (not (string= ada-prj-default-project-file "")))
	    (set 'selected ada-prj-default-project-file))
      
      ;;  2nd case: If the buffer already has a project file, use it
      (if (my-local-variable-if-set-p 'ada-prj-prj-file (current-buffer))
	  (set 'selected ada-prj-prj-file)
	
	(let* ((current-file (buffer-file-name))
	       (first-choice (concat
			      (file-name-sans-extension current-file)
			      ada-project-file-extension))
	       (dir          (file-name-directory current-file))
	       
	       ;; on Emacs 20.2, directory-files does not work if
	       ;; parse-sexp-lookup-properties is set
	       (parse-sexp-lookup-properties nil)
	       (prj-files    (directory-files
			      dir t
			      (concat ".*" (regexp-quote ada-project-file-extension) "$")))
	       (choice       nil)
	       (default      (assoc dir ada-xref-default-prj-file)))
	  
	  (cond
	   
	   ;;  3rd case: a project file is already associated with the directory
	   (default
	     (set 'selected (cdr default)))
	   
	   ;;  4th case: the user has set a default project file for every file
	   ((and ada-prj-default-project-file
		 (not (string= ada-prj-default-project-file "")))
	    (set 'selected ada-prj-default-project-file))
	   
	   ;;  5th case: there is a project file with the same name as the Ada file,
	   ;;  but not the same extension.
	   ((file-exists-p first-choice)
	    (set 'selected first-choice))
	   
	   ;;  6th case: only one project file was found in the current directory
	   ((= (length prj-files) 1)
	    (set 'selected (car prj-files)))
	   
	   ;;  7th case: if there are multiple files, ask the user
	   ((and (> (length prj-files) 1) (not no-user-question))
	    (save-window-excursion
	      (with-output-to-temp-buffer "*choice list*"
		(princ "There are more than one possible project file. Which one should\n")
		(princ "be used ?\n\n")
		(princ "  no.   file name  \n")
		(princ "  ---   ------------------------\n")
		(let ((counter 1))
		  (while (<= counter (length prj-files))
		    (princ (format "  %2d)    %s\n"
				   counter
				   (nth (1- counter) prj-files)))
		    (setq counter (1+ counter))
		    ))) ; end of with-output-to ...
	      (setq choice nil)
	      (while (or
		      (not choice)
		      (not (integerp choice))
		      (< choice 1)
		      (> choice (length prj-files)))
		(setq choice (string-to-int
			      (read-from-minibuffer "Enter No. of your choice: "))))
	      (set 'selected (nth (1- choice) prj-files))))
	   
	   ;; 8th case: no project file was found in the directory, ask a name to the
	   ;; user, using as a default value the last one entered by the user
	   ((= (length prj-files) 0)
	    (unless (or no-user-question (not ada-always-ask-project))
	      (setq ada-last-prj-file
		    (read-file-name "project file:" nil ada-last-prj-file))
	      (unless (string= ada-last-prj-file "")
		(set 'selected ada-last-prj-file))))
	   ))))
    selected
    ))


(defun ada-parse-prj-file (prj-file)
  "Reads and parses the PRJ-FILE file if it was found.
The current buffer should be the ada-file buffer."
  (if prj-file
      (let (project src_dir obj_dir casing
            (ada-buffer (current-buffer)))
	(set 'prj-file (expand-file-name prj-file))

	;;  Initialize the project with the default values
	(ada-xref-set-default-prj-values 'project (current-buffer))

	;;  Do not use find-file below, since we don't want to show this
	;;  buffer. If the file is open through speedbar, we can't use
	;;  find-file anyway, since the speedbar frame is special and does not
	;;  allow the selection of a file in it.

	(set-buffer (find-file-noselect prj-file))
	
	(widen)
	(goto-char (point-min))
	
	;;  Now overrides these values with the project file
	(while (not (eobp))
	  (if (looking-at "^\\([^=]+\\)=\\(.*\\)")
	      (cond
	       ((string= (match-string 1) "src_dir")
		(add-to-list 'src_dir
			     (file-name-as-directory (match-string 2))))
	       ((string= (match-string 1) "obj_dir")
		(add-to-list 'obj_dir
			     (file-name-as-directory (match-string 2))))
	       ((string= (match-string 1) "casing")
		(set 'casing (cons (match-string 2) casing)))
	       ((string= (match-string 1) "build_dir")
		(set 'project
		     (plist-put project 'build_dir
				(file-name-as-directory (match-string 2)))))
	       (t
		(set 'project (plist-put project (intern (match-string 1))
					 (match-string 2))))))
	  (forward-line 1))
	
	(if src_dir (set 'project (plist-put project 'src_dir
					     (reverse src_dir))))
	(if obj_dir (set 'project (plist-put project 'obj_dir
					     (reverse obj_dir))))
	(if casing  (set 'project (plist-put project 'casing  casing)))

	;;  Memorize the newly read project file
	(if (assoc prj-file ada-xref-project-files)
	    (setcdr (assoc prj-file ada-xref-project-files) project)
	  (add-to-list 'ada-xref-project-files (cons prj-file project)))
	
	;; Sets up the compilation-search-path so that Emacs is able to
	;; go to the source of the errors in a compilation buffer
	(setq compilation-search-path (ada-get-absolute-dir-list
				       (plist-get project 'src_dir)
				       (plist-get project 'build_dir)))
	
	;;  Associate each source directory in the project file with this file
	(mapcar (lambda (x)
		  (if (not (assoc (expand-file-name x)
				  ada-xref-default-prj-file))
		      (setq ada-xref-default-prj-file
			    (cons (cons (expand-file-name x) prj-file)
				  ada-xref-default-prj-file))))
		compilation-search-path)
	
	;; Add the directories to the search path for ff-find-other-file
	;; Do not add the '/' or '\' at the end
	(set (make-local-variable 'ff-search-directories)
	     (append (mapcar 'directory-file-name compilation-search-path)
		     ada-search-directories))
	
	;; Kill the .ali buffer
	(kill-buffer nil)
	(set-buffer ada-buffer)

	;;  Setup the project file for the current buffer
	(set (make-local-variable 'ada-prj-prj-file) prj-file)

	)
    ))
      
    
(defun ada-find-references (&optional pos)
  "Find all references to the entity under POS.
Calls gnatfind to find the references."
  (interactive "")
  (unless pos
    (set 'pos (point)))
  (ada-require-project-file)

  (let* ((identlist (ada-read-identifier pos))
         (alifile (ada-get-ali-file-name (ada-file-of identlist)))
	 (process-environment (ada-set-environment)))

    (set-buffer (get-file-buffer (ada-file-of identlist)))

    ;;  if the file is more recent than the executable
    (if (or (buffer-modified-p (current-buffer))
            (file-newer-than-file-p (ada-file-of identlist) alifile))
        (ada-find-any-references (ada-name-of identlist)
                                 (ada-file-of identlist)
                                 nil nil)
      (ada-find-any-references (ada-name-of identlist)
                               (ada-file-of identlist)
                               (ada-line-of identlist)
                               (ada-column-of identlist))))
  )

(defun ada-find-any-references (entity &optional file line column)
  "Search for references to any entity whose name is ENTITY.
ENTITY was first found the location given by FILE, LINE and COLUMN."
  (interactive "sEntity name: ")
  (ada-require-project-file)

  (let* ((command (concat "gnatfind -rf " entity
                          (if file (concat ":" (file-name-nondirectory file)))
                          (if line (concat ":" line))
                          (if column (concat ":" column)))))

    ;;  If a project file is defined, use it
    (if (my-local-variable-if-set-p 'ada-prj-prj-file (current-buffer))
        (setq command (concat command " -p" ada-prj-prj-file)))

    (compile-internal command "No more references" "gnatfind")

    ;;  Hide the "Compilation" menu
    (save-excursion
      (set-buffer "*gnatfind*")
      (local-unset-key [menu-bar compilation-menu]))
    )
  )

(defun ada-buffer-list ()
  "Display a buffer with all the Ada buffers and their associated project."
  (interactive)
  (save-excursion
    (set-buffer (get-buffer-create "*Buffer List*"))
    (setq buffer-read-only nil)
    (erase-buffer)
    (setq standard-output (current-buffer))
    (princ "The following line is a list showing the associations between
directories and project file. It has the format : ((directory_1 . project_file1)
(directory2 . project_file2)...)\n\n")
    (princ ada-xref-default-prj-file)
    (princ "\n
 Buffer              Mode         Project file
 ------              ----         ------------
\n")
    (let ((bl (buffer-list)))
      (while bl
        (let* ((buffer (car bl))
               (buffer-name (buffer-name buffer))
               this-buffer-mode-name
               this-buffer-project-file)
          (save-excursion
            (set-buffer buffer)
            (setq this-buffer-mode-name
                  (if (eq buffer standard-output)
                      "Buffer Menu" mode-name))
            (if (string= this-buffer-mode-name
                         "Ada")
                (setq this-buffer-project-file
                      (if ( my-local-variable-if-set-p 'ada-prj-prj-file
                                                   (current-buffer))
                          (expand-file-name ada-prj-prj-file)
                        ""))))
          (if (string= this-buffer-mode-name
                         "Ada")
              (progn
                (princ (format "%-19s  "  buffer-name))
                  (princ (format "%-6s " this-buffer-mode-name))
                  (princ this-buffer-project-file)
                  (princ "\n")
                  ))
          ) ;; end let*
        (setq bl (cdr bl))
        ) ;; end while
      );; end let
    ) ;; end save-excursion
  (display-buffer "*Buffer List*")
  (other-window 1)
  )

(defun ada-change-prj (filename)
  "Set FILENAME to be the project file for current buffer."
  (interactive "fproject file:")

  ;; make sure we are using an Ada file
  (if (not (string= mode-name "Ada"))
    (error "You must be in ada-mode to use this function"))

  (set (make-local-variable 'ada-prj-prj-file) filename)
  (ada-parse-prj-file filename)
  )

(defun ada-change-default-prj (filename)
  "Set FILENAME to be the default project file for the current directory."
  (interactive "ffile name:")
  (let ((dir (file-name-directory (buffer-file-name)))
	(prj (expand-file-name filename)))

    ;;  Associate the directory with a project file
    (if (assoc dir ada-xref-default-prj-file)
	(setcdr (assoc dir ada-xref-default-prj-file) prj)
      (add-to-list 'ada-xref-default-prj-file (list dir prj)))

    ;; Reparse the project file
    (ada-parse-prj-file filename)))


;; ----- Identlist manipulation -------------------------------------------
;; An identlist is a vector that is used internally to reference an identifier
;; To facilitate its use, we provide the following macros

(defmacro ada-make-identlist () (make-vector 8 nil))
(defmacro ada-name-of   (identlist)    (list 'aref identlist 0))
(defmacro ada-line-of   (identlist)    (list 'aref identlist 1))
(defmacro ada-column-of (identlist)    (list 'aref identlist 2))
(defmacro ada-file-of   (identlist)    (list 'aref identlist 3))
(defmacro ada-ali-index-of    (identlist) (list 'aref identlist 4))
(defmacro ada-declare-file-of (identlist) (list 'aref identlist 5))
(defmacro ada-references-of   (identlist) (list 'aref identlist 6))
(defmacro ada-on-declaration  (identlist) (list 'aref identlist 7))

(defmacro ada-set-name         (identlist name) (list 'aset identlist 0 name))
(defmacro ada-set-line         (identlist line) (list 'aset identlist 1 line))
(defmacro ada-set-column       (identlist col)  (list 'aset identlist 2 col))
(defmacro ada-set-file         (identlist file) (list 'aset identlist 3 file))
(defmacro ada-set-ali-index   (identlist index) (list 'aset identlist 4 index))
(defmacro ada-set-declare-file (identlist file) (list 'aset identlist 5 file))
(defmacro ada-set-references   (identlist ref)  (list 'aset identlist 6 ref))
(defmacro ada-set-on-declaration (ident value) (list 'aset ident 7 value))

(defsubst ada-get-ali-buffer (file)
  "Reads the ali file into a new buffer, and returns this buffer's name"
  (find-file-noselect (ada-get-ali-file-name file)))



;; ----- Identifier Completion --------------------------------------------
(defun ada-complete-identifier (pos)
  "Tries to complete the identifier around POS.
The feature is only available if the files where compiled not using the -gnatx
option."
  (interactive "d")
  (ada-require-project-file)

  ;; Initialize function-local variables and jump to the .ali buffer
  ;; Note that for regexp search is case insensitive too
  (let* ((curbuf (current-buffer))
         (identlist (ada-read-identifier pos))
         (sofar (concat "^[0-9]+[a-zA-Z][0-9]+[ *]\\("
                        (regexp-quote (ada-name-of identlist))
                        "[a-zA-Z0-9_]*\\)"))
         (completed nil)
         (symalist nil))

    ;; Open the .ali file
    (set-buffer (ada-get-ali-buffer (buffer-file-name)))
    (goto-char (point-max))

    ;; build an alist of possible completions
    (while (re-search-backward sofar nil t)
      (setq symalist (cons (cons (match-string 1) nil) symalist)))

    (setq completed  (try-completion "" symalist))

    ;; kills .ali buffer
    (kill-buffer nil)

    ;; deletes the incomplete identifier in the buffer
    (set-buffer curbuf)
    (looking-at "[a-zA-Z0-9_]+")
    (replace-match "")
    ;; inserts the completed symbol
    (insert completed)
    ))

;; ----- Cross-referencing ----------------------------------------

(defun ada-point-and-xref ()
 "Calls `mouse-set-point' and then `ada-goto-declaration'."
  (interactive)
  (mouse-set-point last-input-event)
  (ada-goto-declaration (point)))

(defun ada-goto-declaration (pos)
  "Display the declaration of the identifier around POS.
The declaration is shown in another buffer if `ada-xref-other-buffer' is
non-nil."
  (interactive "d")
  (ada-require-project-file)
  (push-mark pos)
  (ada-xref-push-pos (buffer-file-name) pos)
  (ada-find-in-ali (ada-read-identifier pos)))

(defun ada-goto-declaration-other-frame (pos)
  "Display the declaration of the identifier around POS.
The declation is shown in another frame if `ada-xref-other-buffer' is non-nil."
  (interactive "d")
  (ada-require-project-file)
  (push-mark pos)
  (ada-xref-push-pos (buffer-file-name) pos)
  (ada-find-in-ali (ada-read-identifier pos) t))

(defun ada-remote (command)
  "Return the remote version of COMMAND, or COMMAND if remote_machine is nil."
  (let ((machine (ada-xref-get-project-field 'remote_machine)))
    (if (or (not machine) (string= machine ""))
	command
      (format "%s %s '(%s)'"
	      remote-shell-program
	      machine
	      command))))

(defun ada-get-absolute-dir (dir root-dir)
  "Returns the absolute directory corresponding to DIR.
If DIR is a relative directory, the value of ROOT-DIR is added in front."
  (if (= (string-to-char dir) ?/)
      dir
    (concat root-dir dir)))

(defun ada-get-absolute-dir-list (dir-list root-dir)
  "Returns the list of absolute directories found in dir-list.
If a directory is a relative directory, the value of ROOT-DIR is added in
front."
  (mapcar (lambda (x) (ada-get-absolute-dir x root-dir)) dir-list))

(defun ada-set-environment ()
  "Return the new value for process-environment.
It modifies the source path and object path with the values found in the
project file."
  (let ((include   (getenv "ADA_INCLUDE_PATH"))
	(objects   (getenv "ADA_OBJECTS_PATH"))
	(build-dir (ada-xref-get-project-field 'build_dir)))
    (if include
	(set 'include (concat include path-separator)))
    (if objects
	(set 'objects (concat objects path-separator)))
    (cons
     (concat "ADA_INCLUDE_PATH="
	     include
	     (mapconcat (lambda(x) (ada-get-absolute-dir x build-dir))
			(ada-xref-get-project-field 'src_dir)
			path-separator))
     (cons
      (concat "ADA_OBJECTS_PATH="
	      objects
	      (mapconcat (lambda(x) (ada-get-absolute-dir x build-dir))
			 (ada-xref-get-project-field 'obj_dir)
			 path-separator))
      process-environment))))

(defun ada-compile-application (&optional arg)
  "Compiles the application, using the command found in the project file.
If ARG is not nil, ask for user confirmation."
  (interactive "P")
  (ada-require-project-file)
  (let ((cmd (ada-xref-get-project-field 'make_cmd))
	(process-environment (ada-set-environment))
	(compilation-scroll-output t))

    (set 'compilation-search-path
	 (ada-get-absolute-dir-list (ada-xref-get-project-field 'src_dir)
				    (ada-xref-get-project-field 'build_dir)))

    ;;  If no project file was found, ask the user
    (unless cmd
      (setq cmd "" arg t))

    (compile (ada-remote
	      (if (or ada-xref-confirm-compile arg)
		  (read-from-minibuffer "enter command to compile: " cmd)
		cmd)))
  ))

(defun ada-compile-current (&optional arg prj-field)
  "Recompile the current file.
If ARG is not nil, ask for user confirmation of the command.
PRJ-FIELD is the name of the field to use in the project file to get the
command, and should be either comp_cmd (default) or check_cmd."
  (interactive "P")
  (ada-require-project-file)
  (let* ((field (if prj-field prj-field 'comp_cmd))
	 (cmd (ada-xref-get-project-field field))
	 (process-environment (ada-set-environment))
	 (compilation-scroll-output t))
    
    (set 'compilation-search-path
	 (ada-get-absolute-dir-list (ada-xref-get-project-field 'src_dir)
				    (ada-xref-get-project-field 'build_dir)))

    ;;  If no project file was found, ask the user
    (if cmd
	(set 'cmd (concat cmd " " (ada-convert-file-name (buffer-file-name))))
      (setq cmd "" arg t))
    
    (compile (ada-remote
	      (if (or ada-xref-confirm-compile arg)
		  (read-from-minibuffer "enter command to compile: " cmd)
		cmd)))))

(defun ada-check-current (&optional arg)
  "Recompile the current file.
If ARG is not nil, ask for user confirmation of the command."
  (interactive "P")
  (ada-compile-current arg 'check_cmd))

(defun ada-run-application (&optional arg)
  "Run the application.
if ARG is not-nil, asks for user confirmation."
  (interactive)
  (ada-require-project-file)

  (let ((machine (ada-xref-get-project-field 'cross_prefix)))
    (if (and machine (not (string= machine "")))
      (error "This feature is not supported yet for cross environments")))

  (let ((command (ada-xref-get-project-field 'run_cmd)))

    ;;  Guess the command if it wasn't specified
    (if (or (not command) (string= command ""))
        (set 'command (file-name-sans-extension (buffer-name))))

    ;; Ask for the arguments to the command if required
    (if (or ada-xref-confirm-compile arg)
	(set 'command (read-from-minibuffer "Enter command to execute: " command)))

    ;; Modify the command to run remotely
    (setq command (ada-remote command))

    ;; Run the command
    (save-excursion
      (set-buffer (get-buffer-create "*run*"))
      (set 'buffer-read-only nil)
      (erase-buffer)
      (goto-char (point-min))
      (insert "\nRunning " command "\n\n")
      (start-process "run" (current-buffer) shell-file-name "-c" command)
      )
    (display-buffer "*run*")

    ;;  change to buffer *run* for interactive programs
    (other-window 1)
    (switch-to-buffer "*run*")
    ))


(defun ada-gdb-application (&optional arg)
  "Start the debugger on the application.
If ARG is non-nil, ask the user to confirm the command."
  (interactive "P")
  (let ((buffer (current-buffer))
        gdb-buffer
	cmd)
    (ada-require-project-file)
    (set 'cmd (ada-xref-get-project-field 'debug_cmd))
    (let ((machine (ada-xref-get-project-field 'remote_machine)))
      (if (and machine (not (string= machine "")))
	  (error "This feature is not supported yet for remote environments")))

    ;;  If the command was not given in the project file, start a bare gdb
    (if (not cmd)
	(set 'cmd (concat ada-prj-default-debugger
			  " "
			  (file-name-sans-extension (buffer-file-name)))))
    (if (or arg ada-xref-confirm-compile)
	(set 'cmd (read-from-minibuffer "enter command to debug: " cmd)))

    ;;  Set the variable gud-last-last-frame so that glide-debug can find
    ;;  the name of the Ada file, and thus of the project file if needed.
    (if ada-prj-prj-file
	(set 'gud-last-last-frame (cons ada-prj-prj-file 1)))
    
    (if (and (string-match "jdb" (comint-arguments cmd 0 0))
	     (boundp 'jdb))
	(funcall (symbol-function 'jdb) cmd)
      (gdb cmd))

    (set 'gdb-buffer (symbol-value 'gud-comint-buffer))
    
    ;;  Switch back to the source buffer
    ;;  and Activate the debug part in the contextual menu
    (switch-to-buffer buffer)

    (if (functionp 'gud-make-debug-menu)
	(funcall (symbol-function 'gud-make-debug-menu)))

    ;;  Warning: on Emacs >= 20.3.8, same-window-regexps includes gud-*,
    ;;  so the following call to display buffer will select the
    ;;  buffer instead of displaying it in another window
    ;;  This is why the second argument to display-buffer is 't'
    (display-buffer gdb-buffer t)
    ))


(defun ada-reread-prj-file (&optional filename)
  "Forces Emacs to read either FILENAME or the project file associated
with the current buffer.
Otherwise, this file is only read once, and never read again.
Since the information in the project file is shared between all buffers, this
automatically modifies the setup for all the Ada buffer that use this file."
  (interactive "P")
  (if filename
      (ada-parse-prj-file filename)
    (ada-parse-prj-file (ada-prj-find-prj-file)))
  )


;; ------ Private routines

(defun ada-xref-current (file &optional ali-file-name)
  "Update the cross-references for FILE.
This in fact recompiles FILE to create ALI-FILE-NAME."
  ;; kill old buffer
  (if (and ali-file-name
           (get-file-buffer ali-file-name))
      (kill-buffer (get-file-buffer ali-file-name)))
  ;; read the project file
  (ada-require-project-file)
  (let* ((cmd (ada-xref-get-project-field 'comp_cmd))
	 (process-environment (ada-set-environment))
	 (compilation-scroll-output t)
	 (name      (ada-convert-file-name (buffer-file-name)))
	 (body-name (ada-get-body-name name)))

    ;; Always recompile the body when we can
    (set 'body-name (or body-name name))

    ;; prompt for command to execute
    (set 'cmd (concat cmd " " body-name))
    (compile (ada-remote
	      (if ada-xref-confirm-compile
		  (read-from-minibuffer "enter command to compile: " cmd)
		cmd)))))

(defun ada-find-file-in-dir (file dir-list)
  "Search for FILE in DIR-LIST."
  (let (found)
    (while (and (not found) dir-list)
      (set 'found (concat (file-name-as-directory (car dir-list))
			  (file-name-nondirectory file)))
      
      (unless (file-exists-p found)
	  (set 'found nil))
      (set 'dir-list (cdr dir-list)))
    found))

(defun ada-find-ali-file-in-dir (file)
  "Find an .ali file in obj_dir. The current buffer must be the Ada file.
Adds build_dir in front of the search path to conform to gnatmake's behavior,
and the standard runtime location at the end."
  (ada-find-file-in-dir file
			(append

			 ;; Add ${build_dir} in front of the path
			 (list (ada-xref-get-project-field 'build_dir))
			 
			 (ada-get-absolute-dir-list
			  (ada-xref-get-project-field 'obj_dir)
			  (ada-xref-get-project-field 'build_dir))

			 ;; Add the standard runtime at the end
			 ada-xref-runtime-library-ali-path)))

(defun ada-find-src-file-in-dir (file)
  "Find a source file in src_dir. The current buffer must be the Ada file.
Adds src_dir in front of the search path to conform to gnatmake's behavior,
and the standard runtime location at the end."
  (ada-find-file-in-dir file
			(append

			 ;; Add ${build_dir} in front of the path
			 (list (ada-xref-get-project-field 'build_dir))

			 (ada-get-absolute-dir-list
			  (ada-xref-get-project-field 'src_dir)
			  (ada-xref-get-project-field 'build_dir))

			 ;; Add the standard runtime at the end
			 ada-xref-runtime-library-specs-path)))
  

(defun ada-get-ali-file-name (file)
  "Create the ali file name for the ada-file FILE.
The file is searched for in every directory shown in the obj_dir lines of
the project file."

  ;; This function has to handle the special case of non-standard
  ;; file names (i.e. not .adb or .ads)
  ;; The trick is the following:
  ;;   1- replace the extension of the current file with .ali,
  ;;      and look for this file
  ;;   2- If this file is found:
  ;;      grep the "^U" lines, and make sure we are not reading the
  ;;      .ali file for a spec file. If we are, go to step 3.
  ;;   3- If the file is not found or step 2 failed:
  ;;      find the name of the "other file", ie the body, and look
  ;;      for its associated .ali file by subtituing the extension

  (save-excursion
    (set-buffer (get-file-buffer file))
    (let ((short-ali-file-name
           (concat (file-name-sans-extension (file-name-nondirectory file))
                   ".ali"))
          ali-file-name)
      ;; First step
      ;; we take the first possible completion
      (setq ali-file-name (ada-find-ali-file-in-dir short-ali-file-name))

      ;; If we have found the .ali file, but the source file was a spec
      ;; with a non-standard name, search the .ali file for the body if any,
      ;; since the xref information is more complete in that one
      (unless ali-file-name
	  (if (not (string= (file-name-extension file) "ads"))
	      (let ((is-spec nil)
		    (specs ada-spec-suffixes)
		    body-ali)
		(while specs
		  (if (string-match (concat (regexp-quote (car specs)) "$")
				    file)
		      (set 'is-spec t))
		  (set 'specs (cdr specs)))

		(if is-spec
		    (set 'body-ali
			 (ada-find-ali-file-in-dir
			  (concat (file-name-sans-extension
				   (file-name-nondirectory
				    (ada-other-file-name)))
				  ".ali"))))
                (if body-ali
                    (set 'ali-file-name body-ali))))
	
        ;;  else we did not find the .ali file
        ;;  Second chance: in case the files do not have standard names (such
        ;;  as for instance file_s.ada and file_b.ada), try to go to the
        ;;  other file and look for its ali file
        (setq short-ali-file-name
              (concat (file-name-sans-extension
		       (file-name-nondirectory (ada-other-file-name)))
                      ".ali"))
        (setq ali-file-name (ada-find-ali-file-in-dir short-ali-file-name))
	
        ;; If still not found, try to recompile the file
        (if (not ali-file-name)
            (progn
              ;; recompile only if the user asked for this
              (if ada-xref-create-ali
                  (ada-xref-current file ali-file-name))
              (error "Ali file not found. Recompile your file")))
        )

      ;; same if the .ali file is too old and we must recompile it
      (if (and (file-newer-than-file-p file ali-file-name)
               ada-xref-create-ali)
          (ada-xref-current file ali-file-name))

      ;; else returns the correct absolute file name
      (expand-file-name ali-file-name))
    ))

(defun ada-get-ada-file-name (file original-file)
  "Create the complete file name (+directory) for FILE.
The original file (where the user was) is ORIGINAL-FILE. Search in project
file for possible paths."

  (save-excursion

    ;; If the buffer for original-file, use it to get the values from the
    ;; project file, otherwise load the file and its project file
    (let ((buffer (get-file-buffer original-file)))
      (if buffer
	  (set-buffer buffer)
	(find-file original-file)
	(ada-require-project-file)))
    
    ;; we choose the first possible completion and we
    ;; return the absolute file name
    (let ((filename (ada-find-src-file-in-dir file)))
      (if filename
          (expand-file-name filename)
        (error (concat
                (file-name-nondirectory file)
                " not found in src_dir. Please check your project file")))

      )))

(defun ada-find-file-number-in-ali (file)
  "Returns the file number for FILE in the associated ali file."
  (set-buffer (ada-get-ali-buffer file))
  (goto-char (point-min))

  (let ((begin (re-search-forward "^D")))
    (beginning-of-line)
    (re-search-forward (concat "^D " (file-name-nondirectory file)))
    (count-lines begin (point))))

(defun ada-read-identifier (pos)
  "Returns the identlist around POS and switch to the .ali buffer."

  ;; If there's a compilation in progress, it's probably because the
  ;; .ali file didn't exist. So we should wait...
  (if compilation-in-progress
      (progn
        (message "Compilation in progress. Try again when it is finished")
        (set 'quit-flag t)))

  ;; If at end of buffer (e.g the buffer is empty), error
  (if (>= (point) (point-max))
      (error "No identifier on point"))
  
  ;; goto first character of the identifier/operator (skip backward < and >
  ;; since they are part of multiple character operators
  (goto-char pos)
  (skip-chars-backward "a-zA-Z0-9_<>")

  ;; check if it really is an identifier
  (if (ada-in-comment-p)
      (error "Inside comment"))

  (let (identifier identlist)
    ;; Just in front of a string => we could have an operator declaration,
    ;; as in "+", "-", ..
    (if (= (char-after) ?\")
        (forward-char 1))

    ;; if looking at an operator
    ;; This is only true if:
    ;;   - the symbol is +, -, ...
    ;;   - the symbol is made of letters, and not followed by _ or a letter
    (if (and (looking-at ada-operator-re)
	     (or (not (= (char-syntax (char-after)) ?w))
		 (not (or (= (char-syntax (char-after (match-end 0))) ?w)
			  (= (char-after (match-end 0)) ?_)))))
        (progn
          (if (and (= (char-before) ?\")
                   (= (char-after (+ (length (match-string 0)) (point))) ?\"))
              (forward-char -1))
          (set 'identifier (regexp-quote (concat "\"" (match-string 0) "\""))))

      (if (ada-in-string-p)
          (error "Inside string or character constant"))
      (if (looking-at (concat ada-keywords "[^a-zA-Z_]"))
          (error "No cross-reference available for reserved keyword"))
      (if (looking-at "[a-zA-Z0-9_]+")
          (set 'identifier (match-string 0))
        (error "No identifier around")))
    
    ;; Build the identlist
    (set 'identlist    (ada-make-identlist))
    (ada-set-name      identlist (downcase identifier))
    (ada-set-line      identlist
		       (number-to-string (count-lines (point-min) (point))))
    (ada-set-column    identlist
		       (number-to-string (1+ (current-column))))
    (ada-set-file      identlist (buffer-file-name))
    identlist
    ))

(defun ada-get-all-references (identlist)
  "Completes and returns IDENTLIST with the information extracted
from the ali file (definition file and places where it is referenced)."
  
  (let ((ali-buffer (ada-get-ali-buffer (ada-file-of identlist)))
	declaration-found)
    (set-buffer ali-buffer)
    (goto-char (point-min))
    (ada-set-on-declaration identlist nil)

    ;; First attempt: we might already be on the declaration of the identifier
    ;; We want to look for the declaration only in a definite interval (after
    ;; the "^X ..." line for the current file, and before the next "^X" line
    
    (if (re-search-forward
	 (concat "^X [0-9]+ " (file-name-nondirectory (ada-file-of identlist)))
	 nil t)
        (let ((bound (save-excursion (re-search-forward "^X " nil t))))
          (set 'declaration-found
	       (re-search-forward
		(concat "^"    (ada-line-of identlist)
			"."    (ada-column-of identlist)
			"[ *]" (ada-name-of identlist)
			" \\(.*\\)$") bound t))
	  (if declaration-found
	      (ada-set-on-declaration identlist t))
	  ))

    ;; If declaration is still nil, then we were not on a declaration, and
    ;; have to fall back on other algorithms

    (unless declaration-found
      
      ;; Since we alread know the number of the file, search for a direct
      ;; reference to it
      (goto-char (point-min))
      (set 'declaration-found t)
      (ada-set-ali-index
       identlist
       (number-to-string (ada-find-file-number-in-ali
			  (ada-file-of identlist))))
      (unless (re-search-forward (concat (ada-ali-index-of identlist)
					 "|\\([0-9]+.[0-9]+ \\)*"
					 (ada-line-of identlist)
					 "[^0-9]"
					 (ada-column-of identlist))
				 nil t)

          ;; if we did not find it, it may be because the first reference
          ;; is not required to have a 'unit_number|' item included.
          ;; Or maybe we are already on the declaration...
          (unless (re-search-forward (concat "^\\([a-zA-Z0-9_.\"]+[ *]\\)*"
					     (ada-line-of identlist)
					     "[^0-9]"
					     (ada-column-of identlist))
				     nil t)
	    
	    ;; If still not found, then either the declaration is unknown
	    ;; or the source file has been modified since the ali file was
	    ;; created
	    (set 'declaration-found nil)
            )
	  )

      ;; Last check to be completly sure we have found the correct line (the
      ;; ali might not be up to date for instance)
      (if declaration-found
	  (progn
	    (beginning-of-line)
	    ;; while we have a continuation line, go up one line
	    (while (looking-at "^\\.")
	      (previous-line 1))
	    (unless (looking-at (concat "[0-9]+.[0-9]+[ *]"
					(ada-name-of identlist) "[ <]"))
	      (set 'declaration-found nil))))

      ;; Still no success ! The ali file must be too old, and we need to
      ;; use a basic algorithm based on guesses. Note that this only happens
      ;; if the user does not want us to automatically recompile files
      ;; automatically
      (unless declaration-found
	(if (ada-xref-find-in-modified-ali identlist)
	    (set 'declaration-found t)
	  ;; no more idea to find the declaration. Give up
	  (progn
	    (kill-buffer ali-buffer)
	    (error (concat "No declaration of " (ada-name-of identlist)
			   " found."))
	    )))
      )

    
    ;; Now that we have found a suitable line in the .ali file, get the
    ;; information available
    (beginning-of-line)
    (if declaration-found
        (let ((current-line (buffer-substring
			     (point) (save-excursion (end-of-line) (point)))))
          (save-excursion
            (next-line 1)
            (beginning-of-line)
            (while (looking-at "^\\.\\(.*\\)")
              (set 'current-line (concat current-line (match-string 1)))
              (next-line 1))
            )

	  (if (re-search-backward "^X [0-9]+ \\([a-zA-Z0-9_.-]+\\)" nil t)
	      (ada-set-declare-file
	       identlist
	       (ada-get-ada-file-name (match-string 1)
				      (ada-file-of identlist))))
	  
	  (ada-set-references   identlist current-line)
	  ))
  ))

(defun ada-xref-find-in-modified-ali (identlist)
  "Find the matching position for IDENTLIST in the current ali buffer.
This function is only called when the file was not up-to-date, so we need
to make some guesses.
This function is disabled for operators, and only works for identifiers."

  (unless (= (string-to-char (ada-name-of identlist)) ?\")
      (progn
        (let ((declist '()) ;;; ( (line_in_ali_file line_in_ada) ( ... ))
	      (my-regexp  (concat "[ *]"
				  (regexp-quote (ada-name-of identlist)) " "))
	      (line-ada "--")
	      (col-ada  "--")
	      (line-ali 0)
	      (len 0)
	      (choice 0)
	      (ali-buffer (current-buffer)))

          (goto-char (point-max))
          (while (re-search-backward my-regexp nil t)
            (save-excursion
              (set 'line-ali (count-lines (point-min) (point)))
              (beginning-of-line)
              ;; have a look at the line and column numbers
              (if (looking-at "^\\([0-9]+\\).\\([0-9]+\\)[ *]")
                  (progn
                    (setq line-ada (match-string 1))
                    (setq col-ada  (match-string 2)))
                (setq line-ada "--")
                (setq col-ada  "--")
                )
              ;; construct a list with the file names and the positions within
              (if (re-search-backward "^X [0-9]+ \\([a-zA-Z0-9._-]+\\)" nil t)
		  (add-to-list
		   'declist (list line-ali (match-string 1) line-ada col-ada))
                )
              )
            )

          ;; how many possible declarations have we found ?
          (setq len (length declist))
          (cond
           ;; none => error
           ((= len 0)
            (kill-buffer (current-buffer))
            (error (concat "No declaration of "
                           (ada-name-of identlist)
                           " recorded in .ali file")))
	   
           ;; one => should be the right one
           ((= len 1)
            (goto-line (caar declist)))
	   
           ;; more than one => display choice list
           (t
            (with-output-to-temp-buffer "*choice list*"

              (princ "Identifier is overloaded and Xref information is not up to date.\n")
              (princ "Possible declarations are:\n\n")
              (princ "  no.   in file                at line  col\n")
              (princ "  ---   ---------------------     ----  ----\n")
              (let ((counter 1))
                (while (<= counter len)
                  (princ (format "  %2d)    %-21s   %4s  %4s\n"
                                 counter
				 (ada-get-ada-file-name
				  (nth 1 (nth (1- counter) declist))
				  (ada-file-of identlist))
                                 (nth 2 (nth (1- counter) declist))
                                 (nth 3 (nth (1- counter) declist))
                                 ))
                  (setq counter (1+ counter))
                  ) ; end of while
                ) ; end of let
              ) ; end of with-output-to ...
            (setq choice nil)
            (while (or
                    (not choice)
                    (not (integerp choice))
                    (< choice 1)
                    (> choice len))
              (setq choice (string-to-int
                            (read-from-minibuffer "Enter No. of your choice: "))))
	    (set-buffer ali-buffer)
            (goto-line (car (nth (1- choice) declist)))
            ))))))


(defun ada-find-in-ali (identlist &optional other-frame)
  "Look in the .ali file for the definition of the identifier in IDENTLIST.
If OTHER-FRAME is non nil, and `ada-xref-other-buffer' is non nil,
opens a new window to show the declaration."

  (ada-get-all-references identlist)
  (let ((ali-line (ada-references-of identlist))
	file  line  col)
    
    ;; If we were on a declaration, go to the body
    (if (ada-on-declaration identlist)
	(if (string-match "\\([0-9]+\\)[bc]\\([0-9]+\\)" ali-line)
	    (progn
	      (setq line (match-string 1 ali-line)
		    col  (match-string 2 ali-line))
	      ;;  it there was a file number in the same line
	      (if (string-match "\\([0-9]+\\)|\\([^|bc]+\\)?[bc]" ali-line)
		  (let ((file-number (match-string 1 ali-line)))
		    (goto-char (point-min))
		    (re-search-forward "^D \\([a-zA-Z0-9_.-]+\\)" nil t
				       (string-to-number file-number))
		    (set 'file (match-string 1))
		    )
		;; Else get the nearest file
		(set 'file (ada-declare-file-of identlist))
		)
	      )
	  (error "No body found"))
    
      ;; Else we were not on the declaration, find the place for it
      (string-match "\\([0-9]+\\)[a-zA-Z+]\\([0-9]+\\)[ *]" ali-line)
      (setq line (match-string 1 ali-line)
	    col  (match-string 2 ali-line)
	    file (ada-declare-file-of identlist))
      )

    ;; Now go to the buffer
    (ada-xref-change-buffer
     (ada-get-ada-file-name file (ada-file-of identlist))
     (string-to-number line)
     (1- (string-to-number col))
     identlist
     other-frame)
    ))

(defun ada-xref-change-buffer
  (file line column identlist &optional other-frame)
  "Select and display FILE, at LINE and COLUMN. The new file is
associated with the same project file as the one for IDENTLIST.
If we do not end on the same identifier as IDENTLIST, find the closest
match. Kills the .ali buffer at the end.
If OTHER-FRAME is non-nil, creates a new frame to show the file."

  (let (prj-file
        declaration-buffer
	(ali-buffer (current-buffer)))

    ;; get the current project file for the source ada file
    (save-excursion
      (set-buffer (get-file-buffer (ada-file-of identlist)))
      (set 'prj-file ada-prj-prj-file))

    ;; Select and display the destination buffer
    (if ada-xref-other-buffer
        (if other-frame
            (find-file-other-frame file)
          (set 'declaration-buffer (find-file-noselect file))
          (set-buffer declaration-buffer)
          (switch-to-buffer-other-window declaration-buffer)
          )
      (find-file file)
      )

    ;; If the new buffer is not already associated with a project file, do it
    (unless (my-local-variable-if-set-p 'ada-prj-prj-file (current-buffer))
      (set (make-local-variable 'ada-prj-prj-file) prj-file))

    ;; move the cursor to the correct position
    (push-mark)
    (goto-line line)
    (move-to-column column)

    ;; If we are not on the identifier, the ali file was not up-to-date.
    ;; Try to find the nearest position where the identifier is found,
    ;; this is probably the right one.
    (unless (looking-at (ada-name-of identlist))
      (ada-xref-search-nearest (ada-name-of identlist)))

    (kill-buffer ali-buffer)))


(defun ada-xref-search-nearest (name)
  "Searches for NAME nearest to the position recorded in the Xref file.
It returns the position of the declaration in the buffer or nil if not found."
  (let ((orgpos (point))
        (newpos nil)
        (diff nil))

    (goto-char (point-max))

    ;; loop - look for all declarations of name in this file
    (while (search-backward name nil t)

      ;; check if it really is a complete Ada identifier
      (if (and
           (not (save-excursion
                  (goto-char (match-end 0))
                  (looking-at "_")))
           (not (ada-in-string-or-comment-p))
           (or
            ;; variable declaration ?
            (save-excursion
              (skip-chars-forward "a-zA-Z_0-9" )
              (ada-goto-next-non-ws)
              (looking-at ":[^=]"))
            ;; procedure, function, task or package declaration ?
            (save-excursion
              (ada-goto-previous-word)
              (looking-at "\\<[pP][rR][oO][cC][eE][dD][uU][rR][eE]\\>\\|\\<[fF][uU][nN][cC][tT][iI][oO][nN]\\>\\|\\<[tT][yY][pP][eE]\\>\\|\\<[tT][aA][sS][kK]\\>\\|\\<[pP][aA][cC][kK][aA][gG][eE]\\>\\|\\<[bB][oO][dD][yY]\\>"))))

          ;; check if it is nearer than the ones before if any
          (if (or (not diff)
                  (< (abs (- (point) orgpos)) diff))
              (progn
                (setq newpos (point)
		      diff (abs (- newpos orgpos))))))
      )

    (if newpos
        (progn
          (message "ATTENTION: this declaration is only a (good) guess ...")
          (goto-char newpos))
      nil)))


;; Find the parent library file of the current file
(defun ada-goto-parent ()
  "Go to the parent library file."
  (interactive)
  (ada-require-project-file)

  (let ((buffer (ada-get-ali-buffer (buffer-file-name)))
        (unit-name nil)
        (body-name nil)
        (ali-name nil))
    (save-excursion
      (set-buffer buffer)
      (goto-char (point-min))
      (re-search-forward "^U \\([^ \t%]+\\)%[bs][ \t]+\\([^ \t]+\\)")
      (setq unit-name (match-string 1))
      (if (not (string-match "\\(.*\\)\\.[^.]+" unit-name))
          (progn
            (kill-buffer buffer)
            (error "No parent unit !"))
        (setq unit-name (match-string 1 unit-name))
        )

      ;; look for the file name for the parent unit specification
      (goto-char (point-min))
      (re-search-forward (concat "^W " unit-name
                                 "%s[ \t]+\\([^ \t]+\\)[ \t]+"
                                 "\\([^ \t\n]+\\)"))
      (setq body-name (match-string 1))
      (setq ali-name (match-string 2))
      (kill-buffer buffer)
      )

    (setq ali-name (ada-find-ali-file-in-dir ali-name))

    (save-excursion
      ;; Tries to open the new ali file to find the spec file
      (if ali-name
          (progn
            (find-file ali-name)
            (goto-char (point-min))
            (re-search-forward (concat "^U " unit-name "%s[ \t]+"
                                       "\\([^ \t]+\\)"))
            (setq body-name (match-string 1))
            (kill-buffer (current-buffer))
            )
        )
      )

    (find-file body-name)
    ))

(defun ada-make-filename-from-adaname (adaname)
  "Determine the filename in which ADANAME is found.
This is a GNAT specific function that uses gnatkrunch."
  (let (krunch-buf)
    (setq krunch-buf (generate-new-buffer "*gkrunch*"))
    (save-excursion
      (set-buffer krunch-buf)
      ;; send adaname to external process `gnatkr'.
      (call-process "gnatkr" nil krunch-buf nil
                    adaname ada-krunch-args)
      ;; fetch output of that process
      (setq adaname (buffer-substring
                     (point-min)
                     (progn
                       (goto-char (point-min))
                       (end-of-line)
                       (point))))
      (kill-buffer krunch-buf)))
  adaname
  )

(defun ada-make-body-gnatstub ()
  "Create an Ada package body in the current buffer.
This function uses the `gnatstub' program to create the body.
This function typically is to be hooked into `ff-file-created-hooks'."
  (interactive)

  (save-some-buffers nil nil)

  (ada-require-project-file)

  (delete-region (point-min) (point-max))

  ;; Call the external process gnatstub
  (let* ((gnatstub-opts (ada-treat-cmd-string ada-gnatstub-opts))
         (filename      (buffer-file-name (car (cdr (buffer-list)))))
         (output        (concat (file-name-sans-extension filename) ".adb"))
         (gnatstub-cmd  (concat "gnatstub " gnatstub-opts " " filename))
         (buffer        (get-buffer-create "*gnatstub*")))

    (save-excursion
      (set-buffer buffer)
      (compilation-minor-mode 1)
      (erase-buffer)
      (insert gnatstub-cmd)
      (newline)
      )
    ;; call gnatstub to create the body file
    (call-process shell-file-name nil buffer nil "-c" gnatstub-cmd)

    (if (save-excursion
          (set-buffer buffer)
          (goto-char (point-min))
          (search-forward "command not found" nil t))
        (progn
          (message "gnatstub was not found -- using the basic algorithm")
          (sleep-for 2)
          (kill-buffer buffer)
          (ada-make-body))

      ;; Else clean up the output

      ;;  Kill the temporary buffer created by find-file
      (set-buffer-modified-p nil)
      (kill-buffer (current-buffer))

      (if (file-exists-p output)
          (progn
            (find-file output)
            (kill-buffer buffer))

        ;; display the error buffer
        (display-buffer buffer)
        )
      )))


(defun ada-xref-initialize ()
  "Function called by `ada-mode-hook' to initialize the ada-xref.el package.
For instance, it creates the gnat-specific menus, sets some hooks for
find-file...."
  (make-local-hook 'ff-file-created-hooks)
  ;; This should really be an `add-hook'.  -stef
  (setq ff-file-created-hooks 'ada-make-body-gnatstub)

  ;; Read the project file and update the search path
  ;; before looking for the other file
  (make-local-hook 'ff-pre-find-hooks)
  (add-hook 'ff-pre-find-hooks 'ada-require-project-file nil t)

  ;; Completion for file names in the mini buffer should ignore .ali files
  (add-to-list 'completion-ignored-extensions ".ali")
  )


;; ----- Add to ada-mode-hook ---------------------------------------------

;;  Set the keymap once and for all, so that the keys set by the user in his
;;  config file are not overwritten every time we open a new file.
(ada-add-ada-menu)
(ada-add-keymap)

(add-hook 'ada-mode-hook 'ada-xref-initialize)

;;  Use ddd as the default debugger if it was found
(if (ada-find-file-in-dir "ddd" exec-path)
    (set 'ada-prj-default-debugger "ddd --tty -fullname -toolbar"))

;;  Initializes the cross references to the runtime library
(ada-initialize-runtime-library)

;;  Add these standard directories to the search path
(set 'ada-search-directories
     (append (mapcar 'directory-file-name ada-xref-runtime-library-specs-path)
	     ada-search-directories))

;;  Make sure that the files are always associated with a project file. Since
;;  the project file has some fields that are used for the editor (like the
;;  casing exceptions), it has to be read before the user edits a file).
(add-hook 'ada-mode-hook
	  (lambda()
	    (let ((file (ada-prj-find-prj-file t)))
	      (if file (ada-reread-prj-file file)))))

(provide 'ada-xref)

;;; ada-xref.el ends here