;;; web-book2.scm  --  Another web book style.
;;; -*- coding: iso-8859-1 -*-
;;;
;;; Copyright 2008, 2012  Ludovic Courtès <ludo@gnu.org>
;;;
;;;
;;; This file is part of Skribilo.
;;;
;;; Skribilo 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 3 of the License, or
;;; (at your option) any later version.
;;;
;;; Skribilo 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 Skribilo.  If not, see <http://www.gnu.org/licenses/>.

(define-module (skribilo package web-book2)
  #:use-module (skribilo ast)
  #:use-module (skribilo engine)
  #:use-module ((skribilo package base) :renamer (symbol-prefix-proc 'b:))

  #:use-module (skribilo utils syntax)
  #:use-module (skribilo utils keywords)

  #:use-module (srfi srfi-1)

  #:replace (chapter section subsection subsubsection))

(skribilo-module-syntax)

;;; Author: Ludovic Courtès
;;;
;;; Commentary:
;;;
;;; Another variant of the web book publishing.  This module is purely
;;; functional, i.e., unlike `web-book', it doesn't modify the HTML engine
;;; customs or writers.  Instead, it replaces the `chapter' and
;;; `(sub)*section' markups with variants that produce a small table of
;;; contents at the beginning of new files.
;;;
;;; Code:


;;;
;;; Small table-of-contents.
;;;

(define %small-toc-class
  "small-toc")

(define (section? n)
  (and (container? n)
       (memq (markup-markup n)
             '(chapter section subsection subsubsection))))

(define (make-small-toc n e)
  ;; Return a small table of contents, for use at the beginning of chapter N.
  (define enclose
    (if (engine-format? "html" e)
        (lambda (toc)
          (b:! (format #f "\n<div class=\"~a\">\n$1\n</div>" %small-toc-class)
               toc))
        (lambda (toc)
          (b:p :class %small-toc-class toc))))

  (define (make-uplink)
    (let ((parent (ast-parent n)))
      (and parent
           (b:ref :handle (b:handle parent)
                  :text (list (b:symbol "uparrow") " "
                              (markup-option parent :title))))))

  (let ((kids (filter section? (markup-body n))))
    (enclose
       (list
        (and (not (null? kids))
             (list "Contents"
                   (b:itemize
                    (map (lambda (section)
                           (b:item (b:ref :handle (b:handle section)
                                          :text (markup-option section :title))))
                         kids))))
        (make-uplink)))))


(define (in-file-of-its-own? n e)
  ;; Return true if node N is in an HTML file of its own.
  (and (engine-format? "html" e)
       (section? n)
       (or (markup-option n :file)
           (let ((custom (symbol-append (markup-markup n) '-file)))
             (engine-custom e custom)))))


;;;
;;; Overrides.
;;;

(define (make-overriding-markup markup)
  ;; Override the `chapter' markup from the `base' package to allow the
  ;; production of a small TOC at the beginning of each chapter.
  (lambda args
    ;;(format (current-error-port) "in new '~a'~%" markup)
    (if (engine-format? "html")
        (apply markup
               (append (concatenate (the-options args))
                       (cons (b:resolve (lambda (n e env)
                                          (let ((p (ast-parent n)))
                                            (and (in-file-of-its-own? p e)
                                                 (make-small-toc p e)))))
                             (the-body args))))
        (apply markup args))))

;; FIXME: With this technique, source location info is lost.

(define chapter
  (make-overriding-markup b:chapter))

(define section
  (make-overriding-markup b:section))

(define subsection
  (make-overriding-markup b:subsection))

(define subsubsection
  (make-overriding-markup b:subsubsection))

;;; web-book2.scm ends here