Virtual Info keyword finder

[Juri Linkov <juri@jurta.org>]

I'd like to close the following TODO item from etc/TODO:

** Replace finder.el with something that generates an Info file
   which gives the same information through a menu structure.

It was easily implementable with a small patch using the virtual
Info manual architecture.  The Top node contains a menu with links
to keyword nodes, and each keyword node contains a menu with links
to nodes with a commentary section:

Index: lisp/info.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/info.el,v
retrieving revision 1.560
diff -c -r1.560 info.el
*** lisp/info.el	2 Jul 2009 22:47:33 -0000	1.560
--- lisp/info.el	11 Jul 2009 20:31:52 -0000
***************
*** 3324,3329 ****
--- 3324,3411 ----
  	      Info-apropos-nodes)
  	(Info-find-node Info-apropos-file nodename)))))
  \f
+ (add-to-list 'Info-virtual-files
+ 	     '("\\`\\*Finder.*\\*\\'"
+ 	       (find-file . Info-finder-find-file)
+ 	       (find-node . Info-finder-find-node)
+ 	       ))
+ 
+ (defvar Info-finder-file "*Finder*"
+   "Info file name of the virtual Info keyword finder manual.")
+ 
+ (defun Info-finder-find-file (filename &optional noerror)
+   "Finder-specific implementation of Info-find-file."
+   filename)
+ 
+ (defvar finder-known-keywords)
+ (defvar finder-package-info)
+ (declare-function find-library-name "find-func" (library))
+ (declare-function lm-commentary "lisp-mnt" (&optional file))
+ 
+ (defun Info-finder-find-node (filename nodename &optional no-going-back)
+   "Finder-specific implementation of Info-find-node-2."
+   (cond
+    ((equal nodename "Top")
+     ;; Display Top menu with descriptions of the keywords
+     (insert (format "\n\^_\nFile: %s,  Node: %s,  Up: (dir)\n\n"
+ 		    Info-finder-file nodename))
+     (insert "Finder Keywords\n")
+     (insert "***************\n\n")
+     (insert "* Menu:\n\n")
+     (mapc
+      (lambda (assoc)
+        (let ((keyword (car assoc)))
+ 	 (insert (format "* %-14s %s.\n"
+ 			 (concat (symbol-name keyword) "::")
+ 			 (cdr assoc)))))
+      finder-known-keywords))
+    ((string-match-p "\\.el\\'" nodename)
+     ;; Display commentary section
+     (insert (format "\n\^_\nFile: %s,  Node: %s,  Up: Top\n\n"
+ 		    Info-finder-file nodename))
+     (insert "Finder Commentary\n")
+     (insert "*****************\n\n")
+     (insert
+      "Commentary section of the package `" nodename "':\n\n")
+     (let ((str (lm-commentary (find-library-name nodename))))
+       (if (null str)
+ 	  (insert "Can't find any Commentary section\n\n")
+ 	(insert
+ 	 (with-temp-buffer
+ 	   (insert str)
+ 	   (goto-char (point-min))
+ 	   (delete-blank-lines)
+ 	   (goto-char (point-max))
+ 	   (delete-blank-lines)
+ 	   (goto-char (point-min))
+ 	   (while (re-search-forward "^;+ ?" nil t)
+ 	     (replace-match "" nil nil))
+ 	   (buffer-string))))))
+    (t
+     ;; Display packages that match the keyword
+     (insert (format "\n\^_\nFile: %s,  Node: %s,  Up: Top\n\n"
+ 		    Info-finder-file nodename))
+     (insert "Finder Packages\n")
+     (insert "***************\n\n")
+     (insert
+      "The following packages match the keyword `" nodename "':\n\n")
+     (insert "* Menu:\n\n")
+     (let ((id (intern nodename)))
+       (mapc
+        (lambda (x)
+ 	 (when (memq id (cadr (cdr x)))
+ 	   (insert (format "* %-16s %s.\n"
+ 			   (concat (car x) "::")
+ 			   (cadr x)))))
+        finder-package-info)))))
+ 
+ ;;;###autoload
+ (defun info-finder ()
+   "Display descriptions of the keywords in the Finder virtual manual."
+   (interactive)
+   (require 'finder)
+   (Info-find-node Info-finder-file "Top"))
+ \f
  (defun Info-undefined ()
    "Make command be undefined in Info."
    (interactive)

-- 
Juri Linkov
http://www.jurta.org/emacs/