--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lisp/packages/igrep.el	Mon Aug 13 08:51:03 2007 +0200
@@ -0,0 +1,800 @@
+;;;; igrep.el --- An improved interface to `grep`.
+
+;;; Description:
+;;; 
+;;; Define the \[igrep] command, which is like \[grep] except that it
+;;; takes three required arguments (PROGRAM, EXPRESSION, and FILES) and
+;;; an optional argument (OPTIONS) instead of just one argument (COMMAND).
+;;; Also define the analogous \[egrep] and \[fgrep] commands for convenience.
+;;; 
+;;; Define the \[igrep-find] command, which is like \[igrep] except that
+;;; it uses `find` to recursively `grep` a directory.  Also define the
+;;; analogous \[egrep-find] and \[fgrep-find] commands for convenience.
+;;; 
+;;; \[igrep] and \[igrep-find] (and their analogues) provide defaults
+;;; for the EXPRESSION and FILES arguments when called interactively,
+;;; and there are global variables that control the syntax of the `grep`
+;;; and `find` shell commands that are executed.  A user option controls
+;;; whether the corresponding GNU (gzip) "zPROGRAM" script is used, to
+;;; `grep` compressed files.
+;;; 
+;;; \[agrep] and \[agrep-find] are also defined as convenient interfaces
+;;; to the approximate `grep` utility, which is distributed with the
+;;; `glimpse' indexing and query tool (available from
+;;; <URL:http://glimpse.cs.arizona.edu:1994/>).
+;;; 
+;;; \[grep] itself is advised to provide the \[igrep] interface when
+;;; called interactively (when called programmatically, it still uses
+;;; the original argument list).  \[grep-find] is defined as an alias
+;;; for \[igrep-find].
+;;; 
+;;; When run interactively from Dired mode, the various \[igrep]
+;;; commands provide defaults for the EXPRESSION and FILES arguments
+;;; that are based on the visited directory (including any inserted
+;;; subdirectories) and the current file.  In addition, the
+;;; \[dired-do-igrep] and \[dired-do-igrep-find] commands are defined
+;;; that respect the `dired-do-*' command calling conventions: a prefix
+;;; argument is interpreted as the number of succeeding files to `grep`,
+;;; otherwise all the marked files are `grep`ed.  \[dired-do-grep] and
+;;; \[dired-do-grep-find] are defined as aliases for \[dired-do-igrep]
+;;; and \[dired-do-igrep-find].
+
+;;; Copyright:
+;;; 
+;;; Copyright © 1994,1995,1996,1997 Kevin Rodgers
+;;; 
+;;; This program is free software; you can redistribute it and/or modify
+;;; it under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 2 of the License, or
+;;; at your option) any later version.
+;;; 
+;;; This program is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;; 
+;;; You should have received a copy of the GNU General Public License
+;;; along with this program; if not, write to the Free Software
+;;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+;;; 
+;;; Neither my former nor current employer (Martin Marietta and
+;;; Information Handling Services, respectively) has disclaimed any
+;;; copyright interest in igrep.el.
+;;; 
+;;; Kevin Rodgers <kevinr@ihs.com>		Project Engineer
+;;; Information Handling Services		Electronic Systems Development
+;;; 15 Inverness Way East, M/S A201		
+;;; Englewood CO 80112 USA			(303)397-2807[voice]/-2779[fax]
+
+;;; Installation:
+;;; 
+;;; 1. Put this file in a directory that is a member of load-path, and
+;;;    byte-compile it (e.g. with `M-x byte-compile-file') for better
+;;;    performance.  You can ignore any warnings about references to free
+;;;    variables and "not known to be defined" functions.
+;;; 2. Put these forms in default.el or ~/.emacs:
+;;;    (autoload (function igrep) "igrep"
+;;;       "*Run `grep` PROGRAM to match EXPRESSION in FILES..." t)
+;;;    (autoload (function igrep-find) "igrep"
+;;;       "*Run `grep` via `find`..." t)
+;;;    (autoload (function dired-do-igrep) "igrep"
+;;;       "*Run `grep` on the marked (or next prefix ARG) files." t)
+;;;    (autoload (function dired-do-igrep-find) "igrep"
+;;;       "*Run `grep` via `find` on the marked (or next prefix ARG) directories." t)
+;;; 2. a. For completeness, you can add these forms as well:
+;;;    (autoload (function grep) "igrep"
+;;;       "*Run `grep` PROGRAM to match EXPRESSION in FILES..." t)
+;;;    (autoload (function egrep) "igrep"
+;;;       "*Run `egrep`..." t)
+;;;    (autoload (function fgrep) "igrep"
+;;;       "*Run `fgrep`..." t)
+;;;    (autoload (function agrep) "igrep"
+;;;       "*Run `agrep`..." t)
+;;;    (autoload (function grep-find) "igrep"
+;;;       "*Run `grep` via `find`..." t)
+;;;    (autoload (function egrep-find) "igrep"
+;;;       "*Run `egrep` via `find`..." t)
+;;;    (autoload (function fgrep-find) "igrep"
+;;;       "*Run `fgrep` via `find`..." t)
+;;;    (autoload (function agrep-find) "igrep"
+;;;       "*Run `agrep` via `find`..." t)
+;;;    (autoload (function dired-do-grep) "igrep"
+;;;       "*Run `grep` on the marked (or next prefix ARG) files." t)
+;;;    (autoload (function dired-do-grep-find) "igrep"
+;;;       "*Run `grep` via `find` on the marked (or next prefix ARG) directories." t)
+;;; 3. If you are running Windows 95/NT, you should install findutils
+;;;    and grep from release 17.1 (or higher) of the Cygnus GNU-Win32
+;;;    distribution.  See <URL:http://www.cygnus.com/misc/gnu-win32/>.
+
+;;; Usage:
+;;; 
+;;; M-x igrep			M-x igrep-find
+;;; M-x  grep			M-x  grep-find
+;;; M-x egrep			M-x egrep-find
+;;; M-x fgrep			M-x fgrep-find
+;;; M-x agrep			M-x agrep-find
+;;; M-x dired-do-igrep		M-x dired-do-igrep-find
+;;; M-x  dired-do-grep		M-x  dired-do-grep-find
+;;; (Each of the 10 igrep commands accepts 1, 2, or 3 `C-u' prefix arguments.
+;;; The 2 Dired commands interpret a prefix argument like the regular `dired-do'
+;;; commands.)
+;;; C-x ` (M-x next-error)	C-c C-c (M-x compile-goto-error) [in *igrep*]
+
+;;; Customization examples:
+;;; 
+;;; To ignore case by default:
+;;; 	(setq igrep-options "-i")
+;;; To search subdirectories by default:
+;;; 	(setq igrep-find t)
+;;; To search files with the GNU (gzip) zgrep script:
+;;; 	(setq igrep-use-zgrep t)
+;;; or define new igrep commands (this works for zegrep and zfgrep as well):
+;;; 	(igrep-define zgrep)		; M-x zgrep
+;;; 	(igrep-find-define zgrep)	; M-x zgrep-find
+;;; To avoid exceeding some shells' limit on command argument length
+;;; (this only works when grep'ing files in the current directory):
+;;; 	(setq igrep-find t
+;;; 	      igrep-find-prune-option "\\! -name .")
+
+;;; To do:
+;;; 
+;;; 1. Delete the *-program variables (except for igrep-program) and
+;;;    replace igrep-options with a table that maps igrep-program to the
+;;;    appropriate options.
+;;; 2. Generalize support for the -prune find clause (e.g. -fstype nfs).
+;;; 3. Provide support for `glimpse`.
+;;; 4. Add a menu interface.
+
+;;; LCD Archive Entry:
+;;; 
+;;; igrep|Kevin Rodgers|kevinr@ihs.com|
+;;; An improved interface to grep/egrep/fgrep; plus recursive `find` versions.|
+;;; 97/02/10|2.56|~/misc/igrep.el.Z|
+
+
+;;; Package interface:
+
+(provide 'igrep)
+
+(require 'backquote)			; igrep-with-default-in-history
+(require 'compile)			; compile-internal and grep-regexp-
+					; alist
+
+(defconst igrep-version "2.56"
+  "Version of igrep.el")
+
+
+;;; User options:
+
+(defvar igrep-options nil
+  "*The options passed by \\[igrep] to `igrep-program', or nil.
+
+`-n' will automatically be passed to `igrep-program', to generate the
+output expected by \\[next-error] and \\[compile-goto-error].
+`-e' will automatically be passed to `igrep-program', if it supports
+that option.")
+
+(defvar igrep-read-options nil
+  "*If non-nil, `\\[igrep]' always prompts for options;
+otherwise, it only prompts when 1 or 3 `C-u's are given as a prefix arg.")
+
+(defvar igrep-read-multiple-files nil
+  "*If non-nil, `\\[igrep]' always prompts for multiple-files;
+otherwise, it only prompts when 2 or 3 `C-u's are given as a prefix arg.")
+
+(defvar igrep-verbose-prompts t
+  "*If t, \\[igrep] prompts for arguments verbosely;
+if not t but non-nil, \\[igrep] prompts for arguments semi-verbosely;
+if nil, \\[igrep] prompts for arguments tersely.")
+
+(defvar igrep-save-buffers 'query
+  "*If t, \\[igrep] first saves each modified file buffer;
+if not t but non-nil, \\[igrep] offers to save each modified file buffer.")
+
+(defvar igrep-program-table		; referenced by igrep-use-zgrep
+  (let ((exec-directories exec-path)
+	(program-obarray (make-vector 11 0)))
+    (while exec-directories
+      (if (and (car exec-directories)
+	       (file-directory-p (car exec-directories)))
+	  (let ((grep-programs
+		 (directory-files (car exec-directories)
+				  nil "grep\\(\\.exe\\)?\\'")))
+	    (while grep-programs
+	      ;; Check `(file-executable-p (car grep-programs))'?
+	      (if (save-match-data
+		    (string-match "\\.exe\\'" (car grep-programs)))
+		  (intern (substring (car grep-programs) 0 -4) program-obarray)
+		(intern (car grep-programs) program-obarray))
+	      (setq grep-programs (cdr grep-programs)))))
+      (setq exec-directories (cdr exec-directories)))
+    program-obarray)
+  "An obarray of available `grep` programs, passed by `igrep-read-program'
+to `completing-read' when `igrep-program' is nil.")
+
+(defvar igrep-use-zgrep
+  (if (intern-soft "zgrep" igrep-program-table)
+      'files)
+  "If t, \\[igrep] searches files using the GNU (gzip) `zPROGRAM` script;
+If not t but non-nil, \\[igrep] searches compressed FILES using `zPROGRAM`;
+if nil, \\[igrep] searches files with `PROGRAM`.")
+
+
+;;; User variables:
+
+(defvar igrep-program "grep"
+  "The default shell program run by \\[igrep] and \\[igrep-find].
+It must take a `grep` expression argument and one or more file names.
+If nil, \\[igrep] prompts for the program to run.")
+
+(defvar igrep-expression-quote-char
+  (if (memq system-type '(ms-dos windows-95 windows-nt emx))
+      ?\"
+    ?')
+  "The character used to delimit the EXPRESSION argument to \\[igrep],
+to protect it from shell filename expansion.")
+
+(defvar igrep-expression-option
+  (if (or (eq system-type 'berkeley-unix)
+	  (save-match-data
+	    (string-match "-sco" system-configuration)))
+      "-e")
+  "If non-nil, the option used to specify the EXPRESSION argument to \\[igrep],
+to protect an initial `-' from option processing.")
+
+(defvar igrep-parenthesis-escape-char
+  (if (memq system-type '(ms-dos windows-95 windows-nt emx))
+      nil
+    ?\\)
+  "If non-nil, the character used by \\[igrep] to escape parentheses,
+to protect them from shell interpretation.")
+
+(defvar igrep-find nil
+  "If non-nil, \\[igrep] searches directories using `find`.
+See \\[igrep-find].")
+
+(defvar igrep-find-prune-options
+  (if (not (save-match-data
+	     (string-match "-sco" system-configuration)))
+      "-name SCCS -o -name RCS")
+  "The `find` clause used to prune directories, or nil;
+see \\[igrep-find].")
+
+(defvar igrep-find-file-options "-type f -o -type l"
+  "The `find` clause used to filter files passed to `grep`, or nil;
+see \\[igrep-find].")
+
+(defvar igrep-find-use-xargs
+  (if (equal (call-process "find" nil nil nil
+			   (if (boundp 'grep-null-device)
+			       grep-null-device
+			     "/dev/null")
+			   "-print0")
+	     0)
+      'gnu)
+  "If `gnu', \\[igrep-find] executes
+	`find ... -print0 | xargs -0 -e grep ...`;
+if not `gnu' but non-nil, \\[igrep-find] executes
+	`find ... -print | xargs -e grep ...`;
+if nil, \\[igrep-find] executes
+	`find ... -exec grep ...`.")
+
+(defvar igrep-program-default nil
+  "The default `grep` program, passed by `igrep-read-program'
+to `completing-read' when `igrep-program' is nil.")
+
+(defvar igrep-expression-history '()
+  "The minibuffer history list for \\[igrep]'s EXPRESSION argument.")
+
+(defvar igrep-files-history '()
+  "The minibuffer history list for \\[igrep]'s FILES argument.")
+
+
+;;; Commands:
+
+;; ;;;###autoload Not ready to replace compile.el's grep yet.  -sb 
+(defadvice grep (around igrep-interface first (&rest grep-args) activate)
+  "If called interactively, use the \\[igrep] interface instead,
+where GREP-ARGS is (PROGRAM EXPRESSION FILES OPTIONS);
+if called programmatically, GREP-ARGS is still (COMMAND)."
+  (interactive (igrep-read-args))
+  (if (interactive-p)
+      (apply (function igrep) grep-args)
+    ad-do-it))
+
+(defalias 'grep-find 'igrep-find)
+
+;;;###autoload
+(defun igrep (program expression files &optional options)
+  "*Run `grep` PROGRAM to match EXPRESSION in FILES.
+The output is displayed in the *igrep* buffer, which \\[next-error] and
+\\[compile-goto-error] parse to find each line of matched text.
+
+PROGRAM may be nil, in which case it defaults to `igrep-program'.
+
+EXPRESSION is automatically delimited by `igrep-expression-quote-char'.
+
+FILES is either a file name pattern (expanded by the shell named by
+`shell-file-name') or a list of file name patterns.
+
+Optional OPTIONS is also passed to PROGRAM; it defaults to `igrep-options'.
+
+If a prefix argument \
+\(\\[universal-argument]\) \
+is given when called interactively,
+or if `igrep-read-options' is set, OPTIONS is read from the minibuffer.
+
+If two prefix arguments \
+\(\\[universal-argument] \\[universal-argument]\) \
+are given when called interactively,
+or if `igrep-read-multiple-files' is set, FILES is read from the minibuffer
+multiple times.
+
+If three prefix arguments \
+\(\\[universal-argument] \\[universal-argument] \\[universal-argument]\) \
+are given when called interactively,
+or if `igrep-read-options' and `igrep-read-multiple-files' are set,
+OPTIONS is read and FILES is read multiple times.
+
+If `igrep-find' is non-nil, the directory or directories
+containing FILES is recursively searched for files whose name matches
+the file name component of FILES \(and whose contents match
+EXPRESSION\)."
+  (interactive
+   (igrep-read-args))
+  (if (null program)
+      (setq program (or igrep-program "grep")))
+  (if (null options)
+      (setq options igrep-options))
+  (if (not (listp files))		; (stringp files)
+      (setq files (list files)))
+  (if (string-match "^[rj]?sh$" (file-name-nondirectory shell-file-name))
+      ;; (restricted, job-control, or standard) Bourne shell doesn't expand ~:
+      (setq files
+	    (mapcar 'expand-file-name files)))
+  (let* ((win32-quote-process-args nil)	; work around NT Emacs hack
+	 (use-zgrep (cond ((eq igrep-use-zgrep t))
+			  (igrep-use-zgrep
+			   (let ((files files)
+				 (compressed-p nil))
+			     (while (and files (not compressed-p))
+			       (if (save-match-data
+				     (string-match "\\.g?[zZ]\\'" (car files)))
+				   (setq compressed-p t))
+			       (setq files (cdr files)))
+			     compressed-p))
+			  (t nil)))
+	 (command (format "%s -n %s %s %c%s%c %s %s"
+			  (if (and use-zgrep
+				   (save-match-data
+				     (not (string-match "\\`z" program))))
+			      (setq program (concat "z" program))
+			    program)
+			  (or options "")
+			  (or igrep-expression-option
+			      (progn
+				(if (save-match-data
+				      (string-match "\\`-" expression))
+				    (setq expression (concat "\\" expression)))
+				""))
+			  igrep-expression-quote-char
+			  expression
+			  igrep-expression-quote-char
+			  (if igrep-find
+			      (if igrep-find-use-xargs
+				  ""
+				"\"{}\"")
+			    (mapconcat (function identity) files " "))
+			  (if (boundp 'grep-null-device)
+			      grep-null-device
+			    "/dev/null"))))
+    (if igrep-find
+	(setq command
+	      (igrep-format-find-command command files)))
+    (cond ((eq igrep-save-buffers t) (save-some-buffers t))
+	  (igrep-save-buffers (save-some-buffers)))
+    (compile-internal command
+		      (format "No more %c%s%c matches"
+			      igrep-expression-quote-char
+			      program
+			      igrep-expression-quote-char)
+		      "igrep" nil grep-regexp-alist)))
+
+;; Analogue commands:
+
+;;;###autoload
+(defmacro igrep-define (analogue-command &rest igrep-bindings)
+  "Define ANALOGUE-COMMAND as an `igrep' analogue command.
+Optional (VARIABLE VALUE) arguments specify temporary bindings for the command."
+;;;  (interactive "SCommand: ") ; C-u => read bindings?
+  (let ((analogue-program (symbol-name analogue-command)))
+    (` (defun (, analogue-command) (&rest igrep-args)
+	 (, (format "*Run `%s` via \\[igrep].
+All arguments \(including prefix arguments, when called interactively\)
+are handled by `igrep'."
+		    analogue-program))
+	 (interactive
+	  (let ((igrep-program (if igrep-program (, analogue-program)))
+		(igrep-program-default (, analogue-program)))
+	    (igrep-read-args)))
+	 (let ( (,@ igrep-bindings))
+	   (apply (function igrep)
+		  (cond ((interactive-p) (car igrep-args))
+			((car igrep-args))
+			(t (, analogue-program)))
+		  (cdr igrep-args)))))))
+
+(igrep-define egrep)
+(igrep-define fgrep)
+(igrep-define agrep
+  (igrep-use-zgrep nil)
+  (igrep-expression-option "-e"))
+
+
+;; Recursive (`find`) commands:
+
+;;;###autoload
+(defun igrep-find (&rest igrep-args)
+  "*Run `grep` via `find`; see \\[igrep] and `igrep-find'.
+All arguments \(including prefix arguments, when called interactively\)
+are handled by `igrep'."
+  (interactive
+   (let ((igrep-find t))
+     (igrep-read-args)))
+  (let ((igrep-find t))
+    (apply (function igrep) igrep-args)))
+
+;; Analogue recursive (`find`) commands:
+
+;;;###autoload
+(defmacro igrep-find-define (analogue-command &rest igrep-bindings)
+  "Define ANALOGUE-COMMAND-find as an `igrep' analogue `find` command.
+Optional (VARIABLE VALUE) arguments specify temporary bindings for the command."
+;;;  (interactive "SCommand: ") ; C-u => read bindings?
+  (let ((analogue-program (symbol-name analogue-command)))
+    (setq analogue-command
+	  (intern (format "%s-find" analogue-command)))
+    (` (defun (, analogue-command) (&rest igrep-args)
+	 (, (format "*Run `%s` via \\[igrep-find].
+All arguments \(including prefix arguments, when called interactively\)
+are handled by `igrep'."
+		    analogue-program))
+	 (interactive
+	  (let ((igrep-program (if igrep-program (, analogue-program)))
+		(igrep-program-default (, analogue-program))
+		(igrep-find t))
+	    (igrep-read-args)))
+	 (let ( (,@ igrep-bindings))
+	   (apply (function igrep-find)
+		  (cond ((interactive-p) (car igrep-args))
+			((car igrep-args))
+			(t (, analogue-program)))
+		  (cdr igrep-args)))))))
+
+(igrep-find-define egrep)
+(igrep-find-define fgrep)
+(igrep-find-define agrep
+  (igrep-use-zgrep nil)
+  (igrep-expression-option "-e"))
+
+
+;; Dired commands:
+
+;;;###autoload
+(defun dired-do-igrep (program expression &optional options arg)
+  "*Run `grep` PROGRAM to match EXPRESSION (with optional OPTIONS)
+on the marked (or next prefix ARG) files."
+  (interactive
+   (let* ((current-prefix-arg nil)
+	  (igrep-args (igrep-read-args t)))
+     ;; Delete FILES:
+     (setcdr (nthcdr 1 igrep-args) (nthcdr 3 igrep-args))
+     ;; Append ARG:
+     (nconc igrep-args (list current-prefix-arg))))
+  (igrep program
+	 expression
+	 (funcall (cond ((fboundp 'dired-get-marked-files) ; GNU Emacs
+			 'dired-get-marked-files)
+			((fboundp 'dired-mark-get-files) ; XEmacs
+			 'dired-mark-get-files))
+		  t arg)
+	 options))
+
+;;;###autoload
+(defalias 'dired-do-grep 'dired-do-igrep)
+
+;; Dired recursive (`find`) commands:
+
+;;;###autoload
+(defun dired-do-igrep-find (program expression &optional options arg)
+  "*Run `grep` PROGRAM to match EXPRESSION (with optional OPTIONS)
+on the marked (or next prefix ARG) directories."
+  (interactive
+   (let* ((current-prefix-arg nil)
+	  (igrep-find t)
+	  (igrep-args (igrep-read-args t)))
+     ;; Delete FILES:
+     (setcdr (nthcdr 1 igrep-args) (nthcdr 3 igrep-args))
+     ;; Append ARG:
+     (nconc igrep-args (list current-prefix-arg))))
+  (let ((igrep-find t))
+    (dired-do-igrep program expression options arg)))
+
+;;;###autoload
+(defalias 'dired-do-grep-find 'dired-do-igrep-find)
+
+
+;;; Utilities:
+
+(defsubst igrep-file-directory (name)
+  ;; Return the directory component of NAME, or "." if it has no
+  ;; directory component.
+  (directory-file-name (or (file-name-directory name)
+			   (file-name-as-directory "."))))
+
+(defsubst igrep-file-pattern (name)
+  ;; Return the file component of NAME, or "*" if it has no file
+  ;; component.
+  (let ((pattern (file-name-nondirectory name)))
+       (if (string= pattern "")
+	   "*"
+	 pattern)))
+
+(defun igrep-format-find-command (command files)
+  ;; Format `grep` COMMAND to be invoked via `find` on FILES.
+  (let ((directories '())
+	(patterns '()))
+    (while files
+      (let ((dir (igrep-file-directory (car files)))
+	    (pat (igrep-file-pattern (car files))))
+	(if (and (not (string= dir "."))
+		 (file-symlink-p dir))
+	    (setq dir (concat dir "/.")))
+	(if (not (member dir directories))
+	    (setq directories (cons dir directories)))
+	(cond ((equal pat "*")
+	       (setq patterns t))
+	      ((and (listp patterns)
+		    (not (member pat patterns)))
+	       (setq patterns (cons pat patterns)))))
+      (setq files (cdr files)))
+    (format (cond ((eq igrep-find-use-xargs 'gnu)
+		   ;; | \\\n
+		   "find %s %s %s %s -print0 | xargs -0 -e %s")
+		  (igrep-find-use-xargs
+		   ;; | \\\n
+		   "find %s %s %s %s -print | xargs -e %s")
+;;;		  ((memq system-type '(ms-dos windows-95 windows-nt emx))
+;;;		   "find %s %s %s %s -exec %s ;")
+		  (t
+		   "find %s %s %s %s -exec %s \\;"))
+	    (mapconcat (function identity) (nreverse directories)
+		       " ")
+	    (if igrep-find-prune-options
+		(format "-type d %c( %s %c) -prune -o"
+			(or igrep-parenthesis-escape-char ? )
+			igrep-find-prune-options
+			(or igrep-parenthesis-escape-char ? ))
+	      "")
+	    (if igrep-find-file-options
+		(format "%c( %s %c)"
+			(or igrep-parenthesis-escape-char ? )
+			igrep-find-file-options
+			(or igrep-parenthesis-escape-char ? ))
+	      "")
+	    (if (listp patterns)
+		(if (cdr patterns)	; (> (length patterns) 1)
+		    (format "%c( %s %c)"
+			    (or igrep-parenthesis-escape-char " ")
+			    (mapconcat (function (lambda (pat)
+						   (format "-name \"%s\"" pat)))
+				       (nreverse patterns)
+				       " -o ")
+			    (or igrep-parenthesis-escape-char " "))
+		  (format "-name \"%s\"" (car patterns)))
+	      "")
+	    command)))
+
+(defun igrep-read-args (&optional no-files)
+  ;; Read and return a list: (PROGRAM EXPRESSION FILES OPTIONS).
+  ;; If NO-FILES is non-nil, then FILES is not read and nil is returned
+  ;; in its place.
+  (let* ((program (igrep-read-program (if igrep-verbose-prompts
+					  (if igrep-find
+					      "[find] "))))
+	 (prompt-prefix (if igrep-verbose-prompts
+			    (apply (function concat)
+				   (if igrep-find
+				       "[find] ")
+				   (if (eq igrep-verbose-prompts t)
+				       (list program " ")))))
+	 (options (igrep-read-options prompt-prefix)))
+    (if (eq igrep-verbose-prompts t)
+	(setq prompt-prefix
+	      (concat prompt-prefix options " ")))
+    (list program
+	  (igrep-read-expression prompt-prefix)
+	  (if (not no-files)
+	      (igrep-read-files prompt-prefix))
+	  options)))
+
+(defsubst igrep-prefix (prefix string)
+  ;; If PREFIX is non-nil, concatenate it and STRING; otherwise, return STRING.
+  (if prefix
+      (concat prefix string)
+    string))
+
+(defun igrep-read-program (&optional prompt-prefix)
+  ;; If igrep-program is nil, read and return a program name from the
+  ;; minibuffer; otherwise, return igrep-program.
+  ;; Optional PROMPT-PREFIX is prepended to the "Program: " prompt.
+  (or igrep-program
+      (let ((prompt "Program: "))
+	(completing-read (igrep-prefix prompt-prefix prompt) igrep-program-table
+			 nil t (or igrep-program-default "grep")))))
+
+(defun igrep-read-options (&optional prompt-prefix)
+  ;; If current-prefix-arg is '(4) or '(64), read and return an options
+  ;; string from the minibuffer; otherwise, return igrep-options.
+  ;; Optional PROMPT-PREFIX is prepended to the "Options: " prompt.
+  (if (or igrep-read-options
+	  (and (consp current-prefix-arg)
+	       (memq (prefix-numeric-value current-prefix-arg)
+		     '(4 64))))
+      (let ((prompt "Options: "))
+	(read-string (igrep-prefix prompt-prefix prompt)
+		     (or igrep-options "-")))
+    igrep-options))
+
+(defun igrep-read-expression (&optional prompt-prefix)
+  ;; Read and return a `grep` expression string from the minibuffer.
+  ;; Optional PROMPT-PREFIX is prepended to the "Expression: " prompt.
+  (let ((default-expression (igrep-default-expression)))
+    (if (string= default-expression "")
+	(read-from-minibuffer (igrep-prefix prompt-prefix "Expression: ")
+			      nil nil nil 'igrep-expression-history)
+      (let ((expression
+	     (igrep-read-string-with-default-in-history
+	      (igrep-prefix prompt-prefix (format "Expression (default %s): "
+						  default-expression))
+	      default-expression
+	      'igrep-expression-history)))
+	(if (string= expression "")
+	    default-expression
+	  expression)))))
+
+(defun igrep-default-expression ()
+  (if (eq major-mode 'dired-mode)
+      (let ((dired-file (dired-get-filename nil t)))
+	(save-excursion
+	  (set-buffer (or (and dired-file (get-file-buffer dired-file))
+			  (other-buffer (current-buffer) t)))
+	  (current-word)))
+    (current-word)))
+
+(defsubst igrep-default-key ()
+  ;; Return the key bound to `exit-minibuffer', preferably "\r".
+  (if (eq (lookup-key minibuffer-local-completion-map "\r")
+	  (function exit-minibuffer))
+      "\r"
+    (where-is-internal (function exit-minibuffer)
+		       minibuffer-local-completion-map
+		       t)))
+
+(defun igrep-read-files (&optional prompt-prefix)
+  ;; Read and return a file name pattern from the minibuffer.  If
+  ;; current-prefix-arg is '(16) or '(64), read multiple file name
+  ;; patterns and return them in a list.  Optional PROMPT-PREFIX is
+  ;; prepended to the "File(s): " prompt.
+  (let* ((dired-subdirectory (if (eq major-mode 'dired-mode)
+				 (dired-current-directory t)))
+	 (default-files (concat dired-subdirectory
+				(igrep-default-file-pattern)))
+	 (prompt (format "File(s) (default %s): " default-files))
+	 (insert-default-directory nil)	; use relative path names
+	 (file (igrep-read-file-name-with-default-in-history
+		(igrep-prefix prompt-prefix prompt)
+		default-files
+		nil
+		'igrep-files-history)))
+    (if (or igrep-read-multiple-files
+	    (and (consp current-prefix-arg)
+		 (memq (prefix-numeric-value current-prefix-arg)
+		       '(16 64))))
+	(let ((files (list file)))
+	  (setq prompt
+		(igrep-prefix prompt-prefix
+			      (if igrep-verbose-prompts
+				  (format "File(s): [Type `%s' when done] "
+					  (key-description (igrep-default-key)))
+				"File(s): ")))
+	  (while (not (string= (setq file
+				     (igrep-read-file-name prompt
+							   nil "" nil nil
+							   'igrep-files-history))
+			       ""))
+	    (setq files (cons file files)))
+	  (nreverse files))
+      file)))
+
+(defmacro igrep-with-default-in-history (default history &rest body)
+  ;; Temporarily append DEFAULT to HISTORY, and execute BODY forms.
+  (` (progn
+       ;; Append default to history:
+       (set history
+	    (cons (, default)
+		  (if (boundp (, history))
+		      (symbol-value (, history))
+		    '())))
+       (unwind-protect			; Make sure the history is restored.
+	   ;; Execute body:
+	   (progn (,@ body))
+	 ;; Delete default from history (undo the append above):
+	 (setcdr (symbol-value (, history))
+		 (nthcdr 2 (symbol-value (, history))))))))
+
+(defun igrep-read-string-with-default-in-history (prompt default history)
+  ;; Read a string from the minibuffer, prompting with string PROMPT.
+  ;; DEFAULT can be inserted into the minibuffer with `previous-
+  ;; history-element'; HISTORY is a symbol whose value (if bound) is a
+  ;; list of previous results, most recent first.
+  (let ((string (igrep-with-default-in-history default history
+		  (read-from-minibuffer prompt nil nil nil history))))
+    ;; Replace empty string in history with default:
+    (if (string= string "")
+	(setcar (symbol-value history) default))
+    string))
+
+(defun igrep-read-file-name-with-default-in-history
+  (prompt &optional default initial history)
+  ;; Read a file name from the minibuffer, prompting with string PROMPT.
+  ;; DEFAULT can be inserted into the minibuffer with `previous-
+  ;; history-element'; HISTORY is a symbol whose value (if any) is a
+  ;; list of previous results, most recent first.
+  (igrep-with-default-in-history default history
+    (igrep-read-file-name prompt nil default nil initial history)))
+
+(defun igrep-read-file-name (prompt
+  &optional directory default existing initial history)
+  ;; Just like read-file-name, but with optional HISTORY.
+  ;; Also: convert DIRECTORY to DIRECTORY/* file name pattern.
+  (let ((file-name
+	 (if history
+	     (let ((file-name-history (symbol-value history)))
+	       (prog1 (read-file-name prompt directory default existing initial)
+		 (set history file-name-history)))
+	   (read-file-name prompt directory default existing initial))))
+    (if (and (not (string-equal file-name ""))
+	     (file-directory-p file-name))
+	(expand-file-name "*" file-name)
+      file-name)))
+
+(defun igrep-default-file-pattern ()
+  ;; Return a shell file name pattern that matches files with the same
+  ;; extension as the file being visited in the current buffer.
+  ;; (Based on other-possibly-interesting-files in ~/as-is/unix.el, by
+  ;; Wolfgang Rupprecht <wolfgang@mgm.mit.edu>.)
+  (if (eq major-mode 'dired-mode)
+      (cond ((stringp dired-directory)
+	     (if (file-directory-p dired-directory)
+		 "*"
+	       (file-name-nondirectory dired-directory))) ; wildcard
+	    ((consp dired-directory)	; (DIR FILE ...)
+	     (mapconcat 'identity (cdr dired-directory) " ")))
+    (if buffer-file-name
+	(let ((file-name (file-name-nondirectory buffer-file-name)))
+	  (concat "*"
+		  (save-match-data
+		    (if (string-match "\\.[^.]+\\(\\.g?[zZ]\\)?$" file-name)
+			(substring file-name
+				   (match-beginning 0) (match-end 0))))))
+      "*")))
+
+;;; Local Variables:
+;;; eval: (put 'igrep-with-default-in-history 'lisp-indent-hook 2)
+;;; eval: (put 'igrep-define 'lisp-indent-hook 1)
+;;; eval: (put 'igrep-find-define 'lisp-indent-hook 1)
+;;; End:
+
+;;;; igrep.el ends here
+