info: Emit dir-category and dir-entry.

Reported by nly <nly@disroot.org>.

* src/guile/skribilo/package/base.scm (document): Add
:info-dir-category and :info-dir-entry.
* doc/user/document.skb: Document them.
* doc/user/user.skb: Pass :info-dir-category.
* src/guile/skribilo/engine/info.scm (scribe-document->info): Create
INFO-DIR-CATEGORY and START-INFO-DIR-ENTRY.

4 files changed, 22 insertions, 5 deletions

diff --git a/doc/user/document.skb b/doc/user/document.skb
index 94c9785..477b972 100644
--- a/doc/user/document.skb
+++ b/doc/user/document.skb
@@ -1,7 +1,7 @@
 ;;; document.skb  --  Document and author
 ;;; -*- coding: iso-8859-1 -*-
 ;;;
-;;; Copyright 2008  Ludovic Courtès <ludo@gnu.org>
+;;; Copyright 2008, 2020  Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright 2003, 2004  Manuel Serrano
 ;;; Copyright 2008  Christopher Allan Webber <cwebber@dustycloud.org>
 ;;;
@@ -56,6 +56,10 @@ or markups.  The keywords will not appear in the final document but only
 as meta-information (e.g., using the HTML `meta' tag) if the engine used
 supports it.")
 	      (:env "A counter environment.")
+	      (:info-dir-category "The name of a category for the
+\"directory\" mechanism of the GNU Info documentation system.")
+	      (:info-dir-entry "Name of the entry for the GNU Info
+directory.")
 	      (#!rest node... "The document nodes."))
 	    :see-also '(author chapter toc))
 
diff --git a/doc/user/user.skb b/doc/user/user.skb
index 885dbb3..6491e42 100644
--- a/doc/user/user.skb
+++ b/doc/user/user.skb
@@ -1,6 +1,6 @@
 ;;; user.skb  --  The Skribilo user manual.     -*- coding: iso-8859-1 -*-
 ;;;
-;;; Copyright 2005, 2006, 2007, 2008, 2009, 2012  Ludovic Courtès <ludo@gnu.org>
+;;; Copyright 2005, 2006, 2007, 2008, 2009, 2012, 2020  Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright 2001, 2002, 2003, 2004  Manuel Serrano
 ;;;
 ;;;
@@ -90,6 +90,8 @@
 (document :title "Skribilo User Manual"
    :keywords '("Skribilo" "Skribe" "User Manual" "text processing"
 	       "HTML" "LaTeX" "Lout" "PostScript" "PDF")
+   :info-dir-category "Document authoring"
+   :info-dir-entry "Authoring documents with Skribilo."
    :env '((example-counter 0) (example-env ()))
    :author (list (author :name "Érick Gallesio"
 		    :affiliation "Université de Nice - Sophia-Antipolis"
diff --git a/src/guile/skribilo/engine/info.scm b/src/guile/skribilo/engine/info.scm
index a66acde..4379cf8 100644
--- a/src/guile/skribilo/engine/info.scm
+++ b/src/guile/skribilo/engine/info.scm
@@ -291,6 +291,16 @@
 	  (output-newline)
 	  (output-flush *margin*))))
 
+   (let ((category (markup-option obj :info-dir-category))
+         (entry    (markup-option obj :info-dir-entry))
+         (name     (basename (info-dest) ".info")))
+     (when category
+       (format #t "INFO-DIR-SECTION ~a~%" category)
+       (format #t "START-INFO-DIR-ENTRY~%")
+       (format #t "* ~a: (~a).      ~a~%"
+               name name (or entry ""))
+       (format #t "END-INFO-DIR-ENTRY~%")))
+
    ;; the main node
    (receive (next prev top)
       (node-next+prev+up obj e)
diff --git a/src/guile/skribilo/package/base.scm b/src/guile/skribilo/package/base.scm
index c28027b..cfc59d3 100644
--- a/src/guile/skribilo/package/base.scm
+++ b/src/guile/skribilo/package/base.scm
@@ -1,7 +1,6 @@
 ;;; base.scm -- The base markup package of Skribe/Skribilo.
-;;; -*- coding: iso-8859-1 -*-
 ;;;
-;;; Copyright 2005, 2006, 2007, 2008, 2009, 2013, 2015, 2016, 2018 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright 2005, 2006, 2007, 2008, 2009, 2013, 2015, 2016, 2018, 2020 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright 2003, 2004  Manuel Serrano
 ;;;
 ;;;
@@ -81,7 +80,9 @@
 			 :key
 			 (ident #f) (class "document")
 			 (title #f) (html-title #f) (author #f)
-			 (ending #f) (keywords '()) (env '()))
+			 (ending #f) (keywords '()) (env '())
+                         (info-dir-category #f)
+                         (info-dir-entry ""))
    (new document
       (markup 'document)
       (ident (or ident