emacs/lisp/man.el

;; Read in and display parts of Unix manual.
;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.

;; 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 1, 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, 675 Mass Ave, Cambridge, MA 02139, USA.

(defun manual-entry (topic &optional section)
  "Display the Unix manual entry for TOPIC.
TOPIC is either the title of the entry, or has the form TITLE(SECTION)
where SECTION is the desired section of the manual, as in \"tty(4)\"."
  (interactive "sManual entry (topic): ")
  (if (= (length topic) 0)
      (error "Must specify topic"))
  (if (and (null section)
	   (string-match "\\`[ \t]*\\([^( \t]+\\)[ \t]*(\\(.+\\))[ \t]*\\'" topic))
      (setq section (substring topic (match-beginning 2)
				     (match-end 2))
	    topic (substring topic (match-beginning 1)
				   (match-end 1))))
  (with-output-to-temp-buffer (concat "*" topic " Manual Entry*")
    (buffer-disable-undo standard-output)
    (save-excursion
      (set-buffer standard-output)
      (message "Looking for formatted entry for %s%s..."
	       topic (if section (concat "(" section ")") ""))
      (let ((dirlist manual-formatted-dirlist)
	    (case-fold-search nil)
	    name)
	(if (and section (or (file-exists-p
			       (setq name (concat manual-formatted-dir-prefix
						  (substring section 0 1)
						  "/"
						  topic "." section)))
			     (file-exists-p
			       (setq name (concat manual-formatted-dir-prefix
						  section
						  "/"
						  topic "." section)))))
	    (insert-man-file name)
	  (while dirlist
	    (let* ((dir (car dirlist))
		   (name1 (concat dir "/" topic "."
				  (or section
				      (substring
					dir
					(1+ (or (string-match "\\.[^./]*$" dir)
						-2))))))
		   completions)
	      (if (file-exists-p name1)
		  (insert-man-file name1)
		(condition-case ()
		    (progn
		      (setq completions (file-name-all-completions
					 (concat topic "." (or section ""))
					 dir))
		      (while completions
			(insert-man-file (concat dir "/" (car completions)))
			(setq completions (cdr completions))))
		  (file-error nil)))
	      (goto-char (point-max)))
	    (setq dirlist (cdr dirlist)))))

      (if (= (buffer-size) 0)
	  (progn
	    (message "No formatted entry, invoking man %s%s..."
		     (if section (concat section " ") "") topic)
	    (if section
		(call-process manual-program nil t nil section topic)
	        (call-process manual-program nil t nil topic))
	    (if (< (buffer-size) 80)
		(progn
		  (goto-char (point-min))
		  (end-of-line)
		  (error (buffer-substring 1 (point)))))))

      (message "Cleaning manual entry for %s..." topic)
      (nuke-nroff-bs)
      (set-buffer-modified-p nil)
      (setq buffer-read-only t)
      (view-mode nil 'bury-buffer)
      (message ""))))

;; Hint: BS stands for more things than "back space"
(defun nuke-nroff-bs ()
  (interactive "*")
  ;; Nuke headers: "MORE(1) UNIX Programmer's Manual MORE(1)"
  ;; We expext to find a footer just before the header except at the beginning.
  (goto-char (point-min))
  (while (re-search-forward "^ *\\([A-Za-z][-_.A-Za-z0-9]*([0-9A-Z]+)\\).*\\1$" nil t)
    (let (start end)
      ;; Put START and END around footer and header and garbage blank lines.
      ;; Fixed line counts are risky, but allow us to preserve
      ;; significant blank lines.
      (setq start (save-excursion (forward-line -10) (point)))
      (setq end (save-excursion (forward-line 4) (point)))
      (delete-region start end)))
  ;; Catch the final footer.
  (goto-char (point-max))
  (delete-region (point) (save-excursion (forward-line -7) (point)))

  ;; Nuke underlining and overstriking (only by the same letter)
  (goto-char (point-min))
  (while (search-forward "\b" nil t)
    (let* ((preceding (char-after (- (point) 2)))
	   (following (following-char)))
      (cond ((= preceding following)
	     ;; x\bx
	     (delete-char -2))
	    ((and (= preceding ?o) (= following ?\+))
	     ;; o\b+ 
	     (delete-char -2))
	    ((= preceding ?\_)
	     ;; _\b
	     (delete-char -2))
	    ((= following ?\_)
	     ;; \b_
	     (delete-region (1- (point)) (1+ (point)))))))

  ;; Zap ESC7, ESC8, and ESC9.
  ;; This is for Sun man pages like "man 1 csh"
  (goto-char (point-min))
  (while (re-search-forward "\e[789]" nil t)
    (replace-match ""))

  ;; Crunch blank lines
  (goto-char (point-min))
  (while (re-search-forward "\n\n\n\n*" nil t)
    (replace-match "\n\n"))

  ;; Nuke blanks lines at start.
  (goto-char (point-min))
  (skip-chars-forward "\n")
  (delete-region (point-min) (point)))


(defun insert-man-file (name)
  ;; Insert manual file (unpacked as necessary) into buffer
  (if (or (equal (substring name -2) ".Z")
	  (string-match "/cat[0-9][a-z]?\\.Z/" name))
      (call-process "zcat" name t nil)
    (if (equal (substring name -2) ".z")
	(call-process "pcat" nil t nil name)
      (insert-file-contents name))))