org-mode-mirror/lisp/ox-html.el

;;; ox-html.el --- HTML Back-End for Org Export Engine -*- lexical-binding: t; -*-

;; Copyright (C) 2011-2019 Free Software Foundation, Inc.

;; Author: Carsten Dominik <carsten at orgmode dot org>
;;      Jambunathan K <kjambunathan at gmail dot com>
;; Keywords: outlines, hypermedia, calendar, wp

;; 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; This library implements a HTML back-end for Org generic exporter.
;; See Org manual for more information.

;;; Code:

;;; Dependencies

(require 'cl-lib)
(require 'format-spec)
(require 'ox)
(require 'ox-publish)
(require 'table)


;;; Function Declarations

(declare-function org-id-find-id-file "org-id" (id))
(declare-function htmlize-region "ext:htmlize" (beg end))
(declare-function mm-url-decode-entities "mm-url" ())

(defvar htmlize-css-name-prefix)
(defvar htmlize-output-type)
(defvar htmlize-output-type)
(defvar htmlize-css-name-prefix)

;;; Define Back-End

(org-export-define-backend 'html
  '((bold . org-html-bold)
    (center-block . org-html-center-block)
    (clock . org-html-clock)
    (code . org-html-code)
    (drawer . org-html-drawer)
    (dynamic-block . org-html-dynamic-block)
    (entity . org-html-entity)
    (example-block . org-html-example-block)
    (export-block . org-html-export-block)
    (export-snippet . org-html-export-snippet)
    (fixed-width . org-html-fixed-width)
    (footnote-definition . org-html-footnote-definition)
    (footnote-reference . org-html-footnote-reference)
    (headline . org-html-headline)
    (horizontal-rule . org-html-horizontal-rule)
    (inline-src-block . org-html-inline-src-block)
    (inlinetask . org-html-inlinetask)
    (inner-template . org-html-inner-template)
    (italic . org-html-italic)
    (item . org-html-item)
    (keyword . org-html-keyword)
    (latex-environment . org-html-latex-environment)
    (latex-fragment . org-html-latex-fragment)
    (line-break . org-html-line-break)
    (link . org-html-link)
    (node-property . org-html-node-property)
    (paragraph . org-html-paragraph)
    (plain-list . org-html-plain-list)
    (plain-text . org-html-plain-text)
    (planning . org-html-planning)
    (property-drawer . org-html-property-drawer)
    (quote-block . org-html-quote-block)
    (radio-target . org-html-radio-target)
    (section . org-html-section)
    (special-block . org-html-special-block)
    (src-block . org-html-src-block)
    (statistics-cookie . org-html-statistics-cookie)
    (strike-through . org-html-strike-through)
    (subscript . org-html-subscript)
    (superscript . org-html-superscript)
    (table . org-html-table)
    (table-cell . org-html-table-cell)
    (table-row . org-html-table-row)
    (target . org-html-target)
    (template . org-html-template)
    (timestamp . org-html-timestamp)
    (underline . org-html-underline)
    (verbatim . org-html-verbatim)
    (verse-block . org-html-verse-block))
  :filters-alist '((:filter-options . org-html-infojs-install-script)
		   (:filter-parse-tree . org-html-image-link-filter)
		   (:filter-final-output . org-html-final-function))
  :menu-entry
  '(?h "Export to HTML"
       ((?H "As HTML buffer" org-html-export-as-html)
	(?h "As HTML file" org-html-export-to-html)
	(?o "As HTML file and open"
	    (lambda (a s v b)
	      (if a (org-html-export-to-html t s v b)
		(org-open-file (org-html-export-to-html nil s v b)))))))
  :options-alist
  '((:html-doctype "HTML_DOCTYPE" nil org-html-doctype)
    (:html-container "HTML_CONTAINER" nil org-html-container-element)
    (:description "DESCRIPTION" nil nil newline)
    (:keywords "KEYWORDS" nil nil space)
    (:html-html5-fancy nil "html5-fancy" org-html-html5-fancy)
    (:html-link-use-abs-url nil "html-link-use-abs-url" org-html-link-use-abs-url)
    (:html-link-home "HTML_LINK_HOME" nil org-html-link-home)
    (:html-link-up "HTML_LINK_UP" nil org-html-link-up)
    (:html-mathjax "HTML_MATHJAX" nil "" space)
    (:html-postamble nil "html-postamble" org-html-postamble)
    (:html-preamble nil "html-preamble" org-html-preamble)
    (:html-head "HTML_HEAD" nil org-html-head newline)
    (:html-head-extra "HTML_HEAD_EXTRA" nil org-html-head-extra newline)
    (:subtitle "SUBTITLE" nil nil parse)
    (:html-head-include-default-style
     nil "html-style" org-html-head-include-default-style)
    (:html-head-include-scripts nil "html-scripts" org-html-head-include-scripts)
    (:html-allow-name-attribute-in-anchors
     nil nil org-html-allow-name-attribute-in-anchors)
    (:html-divs nil nil org-html-divs)
    (:html-checkbox-type nil nil org-html-checkbox-type)
    (:html-extension nil nil org-html-extension)
    (:html-footnote-format nil nil org-html-footnote-format)
    (:html-footnote-separator nil nil org-html-footnote-separator)
    (:html-footnotes-section nil nil org-html-footnotes-section)
    (:html-format-drawer-function nil nil org-html-format-drawer-function)
    (:html-format-headline-function nil nil org-html-format-headline-function)
    (:html-format-inlinetask-function
     nil nil org-html-format-inlinetask-function)
    (:html-home/up-format nil nil org-html-home/up-format)
    (:html-indent nil nil org-html-indent)
    (:html-infojs-options nil nil org-html-infojs-options)
    (:html-infojs-template nil nil org-html-infojs-template)
    (:html-inline-image-rules nil nil org-html-inline-image-rules)
    (:html-link-org-files-as-html nil nil org-html-link-org-files-as-html)
    (:html-mathjax-options nil nil org-html-mathjax-options)
    (:html-mathjax-template nil nil org-html-mathjax-template)
    (:html-metadata-timestamp-format nil nil org-html-metadata-timestamp-format)
    (:html-postamble-format nil nil org-html-postamble-format)
    (:html-preamble-format nil nil org-html-preamble-format)
    (:html-self-link-headlines nil nil org-html-self-link-headlines)
    (:html-table-align-individual-fields
     nil nil org-html-table-align-individual-fields)
    (:html-table-caption-above nil nil org-html-table-caption-above)
    (:html-table-data-tags nil nil org-html-table-data-tags)
    (:html-table-header-tags nil nil org-html-table-header-tags)
    (:html-table-use-header-tags-for-first-column
     nil nil org-html-table-use-header-tags-for-first-column)
    (:html-tag-class-prefix nil nil org-html-tag-class-prefix)
    (:html-text-markup-alist nil nil org-html-text-markup-alist)
    (:html-todo-kwd-class-prefix nil nil org-html-todo-kwd-class-prefix)
    (:html-toplevel-hlevel nil nil org-html-toplevel-hlevel)
    (:html-use-infojs nil nil org-html-use-infojs)
    (:html-validation-link nil nil org-html-validation-link)
    (:html-viewport nil nil org-html-viewport)
    (:html-inline-images nil nil org-html-inline-images)
    (:html-table-attributes nil nil org-html-table-default-attributes)
    (:html-table-row-open-tag nil nil org-html-table-row-open-tag)
    (:html-table-row-close-tag nil nil org-html-table-row-close-tag)
    (:html-xml-declaration nil nil org-html-xml-declaration)
    (:html-klipsify-src nil nil org-html-klipsify-src)
    (:html-klipse-css nil nil org-html-klipse-css)
    (:html-klipse-js nil nil org-html-klipse-js)
    (:html-klipse-selection-script nil nil org-html-klipse-selection-script)
    (:infojs-opt "INFOJS_OPT" nil nil)
    ;; Redefine regular options.
    (:creator "CREATOR" nil org-html-creator-string)
    (:with-latex nil "tex" org-html-with-latex)
    ;; Retrieve LaTeX header for fragments.
    (:latex-header "LATEX_HEADER" nil nil newline)))


;;; Internal Variables

(defvar org-html-format-table-no-css)
(defvar htmlize-buffer-places)  ; from htmlize.el

(defvar org-html--pre/postamble-class "status"
  "CSS class used for pre/postamble")

(defconst org-html-doctype-alist
  '(("html4-strict" . "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01//EN\"
\"http://www.w3.org/TR/html4/strict.dtd\">")
    ("html4-transitional" . "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\"
\"http://www.w3.org/TR/html4/loose.dtd\">")
    ("html4-frameset" . "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Frameset//EN\"
\"http://www.w3.org/TR/html4/frameset.dtd\">")

    ("xhtml-strict" . "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\"
\"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">")
    ("xhtml-transitional" . "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\"
\"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">")
    ("xhtml-frameset" . "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Frameset//EN\"
\"http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd\">")
    ("xhtml-11" . "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.1//EN\"
\"http://www.w3.org/TR/xhtml1/DTD/xhtml11.dtd\">")

    ("html5" . "<!DOCTYPE html>")
    ("xhtml5" . "<!DOCTYPE html>"))
  "An alist mapping (x)html flavors to specific doctypes.")

(defconst org-html-html5-elements
  '("article" "aside" "audio" "canvas" "details" "figcaption"
    "figure" "footer" "header" "menu" "meter" "nav" "output"
    "progress" "section" "summary" "video")
  "New elements in html5.

For blocks that should contain headlines, use the HTML_CONTAINER
property on the headline itself.")

(defconst org-html-special-string-regexps
  '(("\\\\-" . "&#x00ad;")		; shy
    ("---\\([^-]\\)" . "&#x2014;\\1")	; mdash
    ("--\\([^-]\\)" . "&#x2013;\\1")	; ndash
    ("\\.\\.\\." . "&#x2026;"))		; hellip
  "Regular expressions for special string conversion.")

(defconst org-html-scripts
  "<script type=\"text/javascript\">
/*
@licstart  The following is the entire license notice for the
JavaScript code in this tag.

Copyright (C) 2012-2019 Free Software Foundation, Inc.

The JavaScript code in this tag is free software: you can
redistribute it and/or modify it under the terms of the GNU
General Public License (GNU GPL) as published by the Free Software
Foundation, either version 3 of the License, or (at your option)
any later version.  The code is distributed WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.

As additional permission under GNU GPL version 3 section 7, you
may distribute non-source (e.g., minimized or compacted) forms of
that code without the copy of the GNU GPL normally required by
section 4, provided you include this license notice and a URL
through which recipients can access the Corresponding Source.


@licend  The above is the entire license notice
for the JavaScript code in this tag.
*/
<!--/*--><![CDATA[/*><!--*/
 function CodeHighlightOn(elem, id)
 {
   var target = document.getElementById(id);
   if(null != target) {
     elem.cacheClassElem = elem.className;
     elem.cacheClassTarget = target.className;
     target.className = \"code-highlighted\";
     elem.className   = \"code-highlighted\";
   }
 }
 function CodeHighlightOff(elem, id)
 {
   var target = document.getElementById(id);
   if(elem.cacheClassElem)
     elem.className = elem.cacheClassElem;
   if(elem.cacheClassTarget)
     target.className = elem.cacheClassTarget;
 }
/*]]>*///-->
</script>"
  "Basic JavaScript that is needed by HTML files produced by Org mode.")

(defconst org-html-style-default
  "<style type=\"text/css\">
 <!--/*--><![CDATA[/*><!--*/
  .title  { text-align: center;
             margin-bottom: .2em; }
  .subtitle { text-align: center;
              font-size: medium;
              font-weight: bold;
              margin-top:0; }
  .todo   { font-family: monospace; color: red; }
  .done   { font-family: monospace; color: green; }
  .priority { font-family: monospace; color: orange; }
  .tag    { background-color: #eee; font-family: monospace;
            padding: 2px; font-size: 80%; font-weight: normal; }
  .timestamp { color: #bebebe; }
  .timestamp-kwd { color: #5f9ea0; }
  .org-right  { margin-left: auto; margin-right: 0px;  text-align: right; }
  .org-left   { margin-left: 0px;  margin-right: auto; text-align: left; }
  .org-center { margin-left: auto; margin-right: auto; text-align: center; }
  .underline { text-decoration: underline; }
  #postamble p, #preamble p { font-size: 90%; margin: .2em; }
  p.verse { margin-left: 3%; }
  pre {
    border: 1px solid #ccc;
    box-shadow: 3px 3px 3px #eee;
    padding: 8pt;
    font-family: monospace;
    overflow: auto;
    margin: 1.2em;
  }
  pre.src {
    position: relative;
    overflow: visible;
    padding-top: 1.2em;
  }
  pre.src:before {
    display: none;
    position: absolute;
    background-color: white;
    top: -10px;
    right: 10px;
    padding: 3px;
    border: 1px solid black;
  }
  pre.src:hover:before { display: inline;}
  /* Languages per Org manual */
  pre.src-asymptote:before { content: 'Asymptote'; }
  pre.src-awk:before { content: 'Awk'; }
  pre.src-C:before { content: 'C'; }
  /* pre.src-C++ doesn't work in CSS */
  pre.src-clojure:before { content: 'Clojure'; }
  pre.src-css:before { content: 'CSS'; }
  pre.src-D:before { content: 'D'; }
  pre.src-ditaa:before { content: 'ditaa'; }
  pre.src-dot:before { content: 'Graphviz'; }
  pre.src-calc:before { content: 'Emacs Calc'; }
  pre.src-emacs-lisp:before { content: 'Emacs Lisp'; }
  pre.src-fortran:before { content: 'Fortran'; }
  pre.src-gnuplot:before { content: 'gnuplot'; }
  pre.src-haskell:before { content: 'Haskell'; }
  pre.src-hledger:before { content: 'hledger'; }
  pre.src-java:before { content: 'Java'; }
  pre.src-js:before { content: 'Javascript'; }
  pre.src-latex:before { content: 'LaTeX'; }
  pre.src-ledger:before { content: 'Ledger'; }
  pre.src-lisp:before { content: 'Lisp'; }
  pre.src-lilypond:before { content: 'Lilypond'; }
  pre.src-lua:before { content: 'Lua'; }
  pre.src-matlab:before { content: 'MATLAB'; }
  pre.src-mscgen:before { content: 'Mscgen'; }
  pre.src-ocaml:before { content: 'Objective Caml'; }
  pre.src-octave:before { content: 'Octave'; }
  pre.src-org:before { content: 'Org mode'; }
  pre.src-oz:before { content: 'OZ'; }
  pre.src-plantuml:before { content: 'Plantuml'; }
  pre.src-processing:before { content: 'Processing.js'; }
  pre.src-python:before { content: 'Python'; }
  pre.src-R:before { content: 'R'; }
  pre.src-ruby:before { content: 'Ruby'; }
  pre.src-sass:before { content: 'Sass'; }
  pre.src-scheme:before { content: 'Scheme'; }
  pre.src-screen:before { content: 'Gnu Screen'; }
  pre.src-sed:before { content: 'Sed'; }
  pre.src-sh:before { content: 'shell'; }
  pre.src-sql:before { content: 'SQL'; }
  pre.src-sqlite:before { content: 'SQLite'; }
  /* additional languages in org.el's org-babel-load-languages alist */
  pre.src-forth:before { content: 'Forth'; }
  pre.src-io:before { content: 'IO'; }
  pre.src-J:before { content: 'J'; }
  pre.src-makefile:before { content: 'Makefile'; }
  pre.src-maxima:before { content: 'Maxima'; }
  pre.src-perl:before { content: 'Perl'; }
  pre.src-picolisp:before { content: 'Pico Lisp'; }
  pre.src-scala:before { content: 'Scala'; }
  pre.src-shell:before { content: 'Shell Script'; }
  pre.src-ebnf2ps:before { content: 'ebfn2ps'; }
  /* additional language identifiers per \"defun org-babel-execute\"
       in ob-*.el */
  pre.src-cpp:before  { content: 'C++'; }
  pre.src-abc:before  { content: 'ABC'; }
  pre.src-coq:before  { content: 'Coq'; }
  pre.src-groovy:before  { content: 'Groovy'; }
  /* additional language identifiers from org-babel-shell-names in
     ob-shell.el: ob-shell is the only babel language using a lambda to put
     the execution function name together. */
  pre.src-bash:before  { content: 'bash'; }
  pre.src-csh:before  { content: 'csh'; }
  pre.src-ash:before  { content: 'ash'; }
  pre.src-dash:before  { content: 'dash'; }
  pre.src-ksh:before  { content: 'ksh'; }
  pre.src-mksh:before  { content: 'mksh'; }
  pre.src-posh:before  { content: 'posh'; }
  /* Additional Emacs modes also supported by the LaTeX listings package */
  pre.src-ada:before { content: 'Ada'; }
  pre.src-asm:before { content: 'Assembler'; }
  pre.src-caml:before { content: 'Caml'; }
  pre.src-delphi:before { content: 'Delphi'; }
  pre.src-html:before { content: 'HTML'; }
  pre.src-idl:before { content: 'IDL'; }
  pre.src-mercury:before { content: 'Mercury'; }
  pre.src-metapost:before { content: 'MetaPost'; }
  pre.src-modula-2:before { content: 'Modula-2'; }
  pre.src-pascal:before { content: 'Pascal'; }
  pre.src-ps:before { content: 'PostScript'; }
  pre.src-prolog:before { content: 'Prolog'; }
  pre.src-simula:before { content: 'Simula'; }
  pre.src-tcl:before { content: 'tcl'; }
  pre.src-tex:before { content: 'TeX'; }
  pre.src-plain-tex:before { content: 'Plain TeX'; }
  pre.src-verilog:before { content: 'Verilog'; }
  pre.src-vhdl:before { content: 'VHDL'; }
  pre.src-xml:before { content: 'XML'; }
  pre.src-nxml:before { content: 'XML'; }
  /* add a generic configuration mode; LaTeX export needs an additional
     (add-to-list 'org-latex-listings-langs '(conf \" \")) in .emacs */
  pre.src-conf:before { content: 'Configuration File'; }

  table { border-collapse:collapse; }
  caption.t-above { caption-side: top; }
  caption.t-bottom { caption-side: bottom; }
  td, th { vertical-align:top;  }
  th.org-right  { text-align: center;  }
  th.org-left   { text-align: center;   }
  th.org-center { text-align: center; }
  td.org-right  { text-align: right;  }
  td.org-left   { text-align: left;   }
  td.org-center { text-align: center; }
  dt { font-weight: bold; }
  .footpara { display: inline; }
  .footdef  { margin-bottom: 1em; }
  .figure { padding: 1em; }
  .figure p { text-align: center; }
  .equation-container {
    display: table;
    text-align: center;
    width: 100%;
  }
  .equation {
    vertical-align: middle;
  }
  .equation-label {
    display: table-cell;
    text-align: right;
    vertical-align: middle;
  }
  .inlinetask {
    padding: 10px;
    border: 2px solid gray;
    margin: 10px;
    background: #ffffcc;
  }
  #org-div-home-and-up
   { text-align: right; font-size: 70%; white-space: nowrap; }
  textarea { overflow-x: auto; }
  .linenr { font-size: smaller }
  .code-highlighted { background-color: #ffff00; }
  .org-info-js_info-navigation { border-style: none; }
  #org-info-js_console-label
    { font-size: 10px; font-weight: bold; white-space: nowrap; }
  .org-info-js_search-highlight
    { background-color: #ffff00; color: #000000; font-weight: bold; }
  .org-svg { width: 90%; }
  /*]]>*/-->
</style>"
  "The default style specification for exported HTML files.
You can use `org-html-head' and `org-html-head-extra' to add to
this style.  If you don't want to include this default style,
customize `org-html-head-include-default-style'.")


;;; User Configuration Variables

(defgroup org-export-html nil
  "Options for exporting Org mode files to HTML."
  :tag "Org Export HTML"
  :group 'org-export)

;;;; Handle infojs

(defvar org-html-infojs-opts-table
  '((path PATH "https://orgmode.org/org-info.js")
    (view VIEW "info")
    (toc TOC :with-toc)
    (ftoc FIXED_TOC "0")
    (tdepth TOC_DEPTH "max")
    (sdepth SECTION_DEPTH "max")
    (mouse MOUSE_HINT "underline")
    (buttons VIEW_BUTTONS "0")
    (ltoc LOCAL_TOC "1")
    (up LINK_UP :html-link-up)
    (home LINK_HOME :html-link-home))
  "JavaScript options, long form for script, default values.")

(defcustom org-html-use-infojs 'when-configured
  "Non-nil when Sebastian Rose's Java Script org-info.js should be active.
This option can be nil or t to never or always use the script.
It can also be the symbol `when-configured', meaning that the
script will be linked into the export file if and only if there
is a \"#+INFOJS_OPT:\" line in the buffer.  See also the variable
`org-html-infojs-options'."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type '(choice
	  (const :tag "Never" nil)
	  (const :tag "When configured in buffer" when-configured)
	  (const :tag "Always" t)))

(defcustom org-html-infojs-options
  (mapcar (lambda (x) (cons (car x) (nth 2 x))) org-html-infojs-opts-table)
  "Options settings for the INFOJS JavaScript.
Each of the options must have an entry in `org-html-infojs-opts-table'.
The value can either be a string that will be passed to the script, or
a property.  This property is then assumed to be a property that is defined
by the Export/Publishing setup of Org.
The `sdepth' and `tdepth' parameters can also be set to \"max\", which
means to use the maximum value consistent with other options."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type
  `(set :greedy t :inline t
	,@(mapcar
	   (lambda (x)
	     (list 'cons (list 'const (car x))
		   '(choice
		     (symbol :tag "Publishing/Export property")
		     (string :tag "Value"))))
	   org-html-infojs-opts-table)))

(defcustom org-html-infojs-template
  "<script type=\"text/javascript\" src=\"%SCRIPT_PATH\">
/**
 *
 * @source: %SCRIPT_PATH
 *
 * @licstart  The following is the entire license notice for the
 *  JavaScript code in %SCRIPT_PATH.
 *
 * Copyright (C) 2012-2019 Free Software Foundation, Inc.
 *
 *
 * The JavaScript code in this tag is free software: you can
 * redistribute it and/or modify it under the terms of the GNU
 * General Public License (GNU GPL) as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option)
 * any later version.  The code is distributed WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.
 *
 * As additional permission under GNU GPL version 3 section 7, you
 * may distribute non-source (e.g., minimized or compacted) forms of
 * that code without the copy of the GNU GPL normally required by
 * section 4, provided you include this license notice and a URL
 * through which recipients can access the Corresponding Source.
 *
 * @licend  The above is the entire license notice
 * for the JavaScript code in %SCRIPT_PATH.
 *
 */
</script>

<script type=\"text/javascript\">

/*
@licstart  The following is the entire license notice for the
JavaScript code in this tag.

Copyright (C) 2012-2019 Free Software Foundation, Inc.

The JavaScript code in this tag is free software: you can
redistribute it and/or modify it under the terms of the GNU
General Public License (GNU GPL) as published by the Free Software
Foundation, either version 3 of the License, or (at your option)
any later version.  The code is distributed WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.

As additional permission under GNU GPL version 3 section 7, you
may distribute non-source (e.g., minimized or compacted) forms of
that code without the copy of the GNU GPL normally required by
section 4, provided you include this license notice and a URL
through which recipients can access the Corresponding Source.


@licend  The above is the entire license notice
for the JavaScript code in this tag.
*/

<!--/*--><![CDATA[/*><!--*/
%MANAGER_OPTIONS
org_html_manager.setup();  // activate after the parameters are set
/*]]>*///-->
</script>"
  "The template for the export style additions when org-info.js is used.
Option settings will replace the %MANAGER-OPTIONS cookie."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'string)

(defun org-html-infojs-install-script (exp-plist _backend)
  "Install script in export options when appropriate.
EXP-PLIST is a plist containing export options.  BACKEND is the
export back-end currently used."
  (unless (or (memq 'body-only (plist-get exp-plist :export-options))
	      (not (plist-get exp-plist :html-use-infojs))
	      (and (eq (plist-get exp-plist :html-use-infojs) 'when-configured)
		   (let ((opt (plist-get exp-plist :infojs-opt)))
		     (or (not opt)
			 (string= "" opt)
			 (string-match "\\<view:nil\\>" opt)))))
    (let* ((template (plist-get exp-plist :html-infojs-template))
	   (ptoc (plist-get exp-plist :with-toc))
	   (hlevels (plist-get exp-plist :headline-levels))
	   (sdepth hlevels)
	   (tdepth (if (integerp ptoc) (min ptoc hlevels) hlevels))
	   (options (plist-get exp-plist :infojs-opt))
	   (infojs-opt (plist-get exp-plist :html-infojs-options))
	   (table org-html-infojs-opts-table)
	   style)
      (dolist (entry table)
	(let* ((opt (car entry))
	       (var (nth 1 entry))
	       ;; Compute default values for script option OPT from
	       ;; `org-html-infojs-options' variable.
	       (default
		 (let ((default (cdr (assq opt infojs-opt))))
		   (if (and (symbolp default) (not (memq default '(t nil))))
		       (plist-get exp-plist default)
		     default)))
	       ;; Value set through INFOJS_OPT keyword has precedence
	       ;; over the default one.
	       (val (if (and options
			     (string-match (format "\\<%s:\\(\\S-+\\)" opt)
					   options))
			(match-string 1 options)
		      default)))
	  (pcase opt
	    (`path (setq template
			 (replace-regexp-in-string
			  "%SCRIPT_PATH" val template t t)))
	    (`sdepth (when (integerp (read val))
		       (setq sdepth (min (read val) sdepth))))
	    (`tdepth (when (integerp (read val))
		       (setq tdepth (min (read val) tdepth))))
	    (_ (setq val
		     (cond
		      ((or (eq val t) (equal val "t")) "1")
		      ((or (eq val nil) (equal val "nil")) "0")
		      ((stringp val) val)
		      (t (format "%s" val))))
	       (push (cons var val) style)))))
      ;; Now we set the depth of the *generated* TOC to SDEPTH,
      ;; because the toc will actually determine the splitting.  How
      ;; much of the toc will actually be displayed is governed by the
      ;; TDEPTH option.
      (setq exp-plist (plist-put exp-plist :with-toc sdepth))
      ;; The table of contents should not show more sections than we
      ;; generate.
      (setq tdepth (min tdepth sdepth))
      (push (cons "TOC_DEPTH" tdepth) style)
      ;; Build style string.
      (setq style (mapconcat
		   (lambda (x)
		     (format "org_html_manager.set(\"%s\", \"%s\");"
			     (car x) (cdr x)))
		   style "\n"))
      (when (and style (> (length style) 0))
	(and (string-match "%MANAGER_OPTIONS" template)
	     (setq style (replace-match style t t template))
	     (setq exp-plist
		   (plist-put
		    exp-plist :html-head-extra
		    (concat (or (plist-get exp-plist :html-head-extra) "")
			    "\n"
			    style)))))
      ;; This script absolutely needs the table of contents, so we
      ;; change that setting.
      (unless (plist-get exp-plist :with-toc)
	(setq exp-plist (plist-put exp-plist :with-toc t)))
      ;; Return the modified property list.
      exp-plist)))

;;;; Bold, etc.

(defcustom org-html-text-markup-alist
  '((bold . "<b>%s</b>")
    (code . "<code>%s</code>")
    (italic . "<i>%s</i>")
    (strike-through . "<del>%s</del>")
    (underline . "<span class=\"underline\">%s</span>")
    (verbatim . "<code>%s</code>"))
  "Alist of HTML expressions to convert text markup.

The key must be a symbol among `bold', `code', `italic',
`strike-through', `underline' and `verbatim'.  The value is
a formatting string to wrap fontified text with.

If no association can be found for a given markup, text will be
returned as-is."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type '(alist :key-type (symbol :tag "Markup type")
		:value-type (string :tag "Format string"))
  :options '(bold code italic strike-through underline verbatim))

(defcustom org-html-indent nil
  "Non-nil means to indent the generated HTML.
Warning: non-nil may break indentation of source code blocks."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'boolean)

;;;; Drawers

(defcustom org-html-format-drawer-function (lambda (_name contents) contents)
  "Function called to format a drawer in HTML code.

The function must accept two parameters:
  NAME      the drawer name, like \"LOGBOOK\"
  CONTENTS  the contents of the drawer.

The function should return the string to be exported.

For example, the variable could be set to the following function
in order to mimic default behavior:

The default value simply returns the value of CONTENTS."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'function)

;;;; Footnotes

(defcustom org-html-footnotes-section "<div id=\"footnotes\">
<h2 class=\"footnotes\">%s: </h2>
<div id=\"text-footnotes\">
%s
</div>
</div>"
  "Format for the footnotes section.
Should contain a two instances of %s.  The first will be replaced with the
language-specific word for \"Footnotes\", the second one will be replaced
by the footnotes themselves."
  :group 'org-export-html
  :type 'string)

(defcustom org-html-footnote-format "<sup>%s</sup>"
  "The format for the footnote reference.
%s will be replaced by the footnote reference itself."
  :group 'org-export-html
  :type 'string)

(defcustom org-html-footnote-separator "<sup>, </sup>"
  "Text used to separate footnotes."
  :group 'org-export-html
  :type 'string)

;;;; Headline

(defcustom org-html-toplevel-hlevel 2
  "The <H> level for level 1 headings in HTML export.
This is also important for the classes that will be wrapped around headlines
and outline structure.  If this variable is 1, the top-level headlines will
be <h1>, and the corresponding classes will be outline-1, section-number-1,
and outline-text-1.  If this is 2, all of these will get a 2 instead.
The default for this variable is 2, because we use <h1> for formatting the
document title."
  :group 'org-export-html
  :type 'integer)

(defcustom org-html-format-headline-function
  'org-html-format-headline-default-function
  "Function to format headline text.

This function will be called with six arguments:
TODO      the todo keyword (string or nil).
TODO-TYPE the type of todo (symbol: `todo', `done', nil)
PRIORITY  the priority of the headline (integer or nil)
TEXT      the main headline text (string).
TAGS      the tags (string or nil).
INFO      the export options (plist).

The function result will be used in the section format string."
  :group 'org-export-html
  :version "26.1"
  :package-version '(Org . "8.3")
  :type 'function)

;;;; HTML-specific

(defcustom org-html-allow-name-attribute-in-anchors nil
  "When nil, do not set \"name\" attribute in anchors.
By default, when appropriate, anchors are formatted with \"id\"
but without \"name\" attribute."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'boolean)

(defcustom org-html-self-link-headlines nil
  "When non-nil, the headlines contain a hyperlink to themselves."
  :group 'org-export-html
  :package-version '(Org . "9.3")
  :type 'boolean
  :safe #'booleanp)

;;;; Inlinetasks

(defcustom org-html-format-inlinetask-function
  'org-html-format-inlinetask-default-function
  "Function called to format an inlinetask in HTML code.

The function must accept seven parameters:
  TODO      the todo keyword, as a string
  TODO-TYPE the todo type, a symbol among `todo', `done' and nil.
  PRIORITY  the inlinetask priority, as a string
  NAME      the inlinetask name, as a string.
  TAGS      the inlinetask tags, as a list of strings.
  CONTENTS  the contents of the inlinetask, as a string.
  INFO      the export options, as a plist

The function should return the string to be exported."
  :group 'org-export-html
  :version "26.1"
  :package-version '(Org . "8.3")
  :type 'function)

;;;; LaTeX

(defcustom org-html-with-latex org-export-with-latex
  "Non-nil means process LaTeX math snippets.

When set, the exporter will process LaTeX environments and
fragments.

This option can also be set with the +OPTIONS line,
e.g. \"tex:mathjax\".  Allowed values are:

  nil           Ignore math snippets.
  `verbatim'    Keep everything in verbatim
  `mathjax', t  Do MathJax preprocessing and arrange for MathJax.js to
                be loaded.
  SYMBOL        Any symbol defined in `org-preview-latex-process-alist',
                e.g., `dvipng'."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type '(choice
	  (const :tag "Do not process math in any way" nil)
	  (const :tag "Leave math verbatim" verbatim)
	  (const :tag "Use MathJax to display math" mathjax)
	  (symbol :tag "Convert to image to display math" :value dvipng)))

;;;; Links :: Generic

(defcustom org-html-link-org-files-as-html t
  "Non-nil means make file links to `file.org' point to `file.html'.
When `org-mode' is exporting an `org-mode' file to HTML, links to
non-html files are directly put into a href tag in HTML.
However, links to other Org files (recognized by the extension
\".org\") should become links to the corresponding HTML
file, assuming that the linked `org-mode' file will also be
converted to HTML.
When nil, the links still point to the plain \".org\" file."
  :group 'org-export-html
  :type 'boolean)

;;;; Links :: Inline images

(defcustom org-html-inline-images t
  "Non-nil means inline images into exported HTML pages.
This is done using an <img> tag.  When nil, an anchor with href is used to
link to the image."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.1")
  :type 'boolean)

(defcustom org-html-inline-image-rules
  '(("file" . "\\.\\(jpeg\\|jpg\\|png\\|gif\\|svg\\)\\'")
    ("http" . "\\.\\(jpeg\\|jpg\\|png\\|gif\\|svg\\)\\'")
    ("https" . "\\.\\(jpeg\\|jpg\\|png\\|gif\\|svg\\)\\'"))
  "Rules characterizing image files that can be inlined into HTML.
A rule consists in an association whose key is the type of link
to consider, and value is a regexp that will be matched against
link's path."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type '(alist :key-type (string :tag "Type")
		:value-type (regexp :tag "Path")))

;;;; Plain Text

(defvar org-html-protect-char-alist
  '(("&" . "&amp;")
    ("<" . "&lt;")
    (">" . "&gt;"))
  "Alist of characters to be converted by `org-html-encode-plain-text'.")

;;;; Src Block

(defcustom org-html-htmlize-output-type 'inline-css
  "Output type to be used by htmlize when formatting code snippets.
Choices are `css' to export the CSS selectors only,`inline-css'
to export the CSS attribute values inline in the HTML or `nil' to
export plain text.  We use as default `inline-css', in order to
make the resulting HTML self-containing.

However, this will fail when using Emacs in batch mode for export, because
then no rich font definitions are in place.  It will also not be good if
people with different Emacs setup contribute HTML files to a website,
because the fonts will represent the individual setups.  In these cases,
it is much better to let Org/Htmlize assign classes only, and to use
a style file to define the look of these classes.
To get a start for your css file, start Emacs session and make sure that
all the faces you are interested in are defined, for example by loading files
in all modes you want.  Then, use the command
`\\[org-html-htmlize-generate-css]' to extract class definitions."
  :group 'org-export-html
  :type '(choice (const css) (const inline-css) (const nil)))

(defcustom org-html-htmlize-font-prefix "org-"
  "The prefix for CSS class names for htmlize font specifications."
  :group 'org-export-html
  :type 'string)

;;;; Table

(defcustom org-html-table-default-attributes
  '(:border "2" :cellspacing "0" :cellpadding "6" :rules "groups" :frame "hsides")
  "Default attributes and values which will be used in table tags.
This is a plist where attributes are symbols, starting with
colons, and values are strings.

When exporting to HTML5, these values will be disregarded."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type '(plist :key-type (symbol :tag "Property")
		:value-type (string :tag "Value")))

(defcustom org-html-table-header-tags '("<th scope=\"%s\"%s>" . "</th>")
  "The opening and ending tags for table header fields.
This is customizable so that alignment options can be specified.
The first %s will be filled with the scope of the field, either row or col.
The second %s will be replaced by a style entry to align the field.
See also the variable `org-html-table-use-header-tags-for-first-column'.
See also the variable `org-html-table-align-individual-fields'."
  :group 'org-export-html
  :type '(cons (string :tag "Opening tag") (string :tag "Closing tag")))

(defcustom org-html-table-data-tags '("<td%s>" . "</td>")
  "The opening and ending tags for table data fields.
This is customizable so that alignment options can be specified.
The first %s will be filled with the scope of the field, either row or col.
The second %s will be replaced by a style entry to align the field.
See also the variable `org-html-table-align-individual-fields'."
  :group 'org-export-html
  :type '(cons (string :tag "Opening tag") (string :tag "Closing tag")))

(defcustom org-html-table-row-open-tag "<tr>"
  "The opening tag for table rows.
This is customizable so that alignment options can be specified.
Instead of strings, these can be a Lisp function that will be
evaluated for each row in order to construct the table row tags.

The function will be called with these arguments:

         `number': row number (0 is the first row)
   `group-number': group number of current row
   `start-group?': non-nil means the row starts a group
     `end-group?': non-nil means the row ends a group
           `top?': non-nil means this is the top row
        `bottom?': non-nil means this is the bottom row

For example:

  (setq org-html-table-row-open-tag
        (lambda (number group-number start-group? end-group-p top? bottom?)
           (cond (top? \"<tr class=\\\"tr-top\\\">\")
                 (bottom? \"<tr class=\\\"tr-bottom\\\">\")
                 (t (if (= (mod number 2) 1)
                        \"<tr class=\\\"tr-odd\\\">\"
                      \"<tr class=\\\"tr-even\\\">\")))))

will use the \"tr-top\" and \"tr-bottom\" classes for the top row
and the bottom row, and otherwise alternate between \"tr-odd\" and
\"tr-even\" for odd and even rows."
  :group 'org-export-html
  :type '(choice :tag "Opening tag"
		 (string :tag "Specify")
		 (function)))

(defcustom org-html-table-row-close-tag "</tr>"
  "The closing tag for table rows.
This is customizable so that alignment options can be specified.
Instead of strings, this can be a Lisp function that will be
evaluated for each row in order to construct the table row tags.

See documentation of `org-html-table-row-open-tag'."
  :group 'org-export-html
  :type '(choice :tag "Closing tag"
		 (string :tag "Specify")
		 (function)))

(defcustom org-html-table-align-individual-fields t
  "Non-nil means attach style attributes for alignment to each table field.
When nil, alignment will only be specified in the column tags, but this
is ignored by some browsers (like Firefox, Safari).  Opera does it right
though."
  :group 'org-export-html
  :type 'boolean)

(defcustom org-html-table-use-header-tags-for-first-column nil
  "Non-nil means format column one in tables with header tags.
When nil, also column one will use data tags."
  :group 'org-export-html
  :type 'boolean)

(defcustom org-html-table-caption-above t
  "When non-nil, place caption string at the beginning of the table.
Otherwise, place it near the end."
  :group 'org-export-html
  :type 'boolean)

;;;; Tags

(defcustom org-html-tag-class-prefix ""
  "Prefix to class names for TODO keywords.
Each tag gets a class given by the tag itself, with this prefix.
The default prefix is empty because it is nice to just use the keyword
as a class name.  But if you get into conflicts with other, existing
CSS classes, then this prefix can be very useful."
  :group 'org-export-html
  :type 'string)

;;;; Template :: Generic

(defcustom org-html-extension "html"
  "The extension for exported HTML files."
  :group 'org-export-html
  :type 'string)

(defcustom org-html-xml-declaration
  '(("html" . "<?xml version=\"1.0\" encoding=\"%s\"?>")
    ("php" . "<?php echo \"<?xml version=\\\"1.0\\\" encoding=\\\"%s\\\" ?>\"; ?>"))
  "The extension for exported HTML files.
%s will be replaced with the charset of the exported file.
This may be a string, or an alist with export extensions
and corresponding declarations.

This declaration only applies when exporting to XHTML."
  :group 'org-export-html
  :type '(choice
	  (string :tag "Single declaration")
	  (repeat :tag "Dependent on extension"
		  (cons (string :tag "Extension")
			(string :tag "Declaration")))))

(defcustom org-html-coding-system 'utf-8
  "Coding system for HTML export.
Use utf-8 as the default value."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'coding-system)

(defcustom org-html-doctype "xhtml-strict"
  "Document type definition to use for exported HTML files.
Can be set with the in-buffer HTML_DOCTYPE property or for
publishing, with :html-doctype."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type (append
	 '(choice)
	 (mapcar (lambda (x) `(const ,(car x))) org-html-doctype-alist)
	 '((string :tag "Custom doctype" ))))

(defcustom org-html-html5-fancy nil
  "Non-nil means using new HTML5 elements.
This variable is ignored for anything other than HTML5 export.

For compatibility with Internet Explorer, it's probably a good
idea to download some form of the html5shiv (for instance
https://code.google.com/p/html5shiv/) and add it to your
HTML_HEAD_EXTRA, so that your pages don't break for users of IE
versions 8 and below."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'boolean)

(defcustom org-html-container-element "div"
  "HTML element to use for wrapping top level sections.
Can be set with the in-buffer HTML_CONTAINER property or for
publishing, with :html-container.

Note that changing the default will prevent you from using
org-info.js for your website."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'string)

(defcustom org-html-divs
  '((preamble  "div" "preamble")
    (content   "div" "content")
    (postamble "div" "postamble"))
  "Alist of the three section elements for HTML export.
The car of each entry is one of `preamble', `content' or `postamble'.
The cdrs of each entry are the ELEMENT_TYPE and ID for each
section of the exported document.

Note that changing the default will prevent you from using
org-info.js for your website."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type '(list :greedy t
	       (list :tag "Preamble"
		     (const :format "" preamble)
		     (string :tag "element") (string :tag "     id"))
	       (list :tag "Content"
		     (const :format "" content)
		     (string :tag "element") (string :tag "     id"))
	       (list :tag "Postamble" (const :format "" postamble)
		     (string :tag "     id") (string :tag "element"))))

(defconst org-html-checkbox-types
  '((unicode .
     ((on . "&#x2611;") (off . "&#x2610;") (trans . "&#x2610;")))
    (ascii .
     ((on . "<code>[X]</code>")
      (off . "<code>[&#xa0;]</code>")
      (trans . "<code>[-]</code>")))
    (html .
	  ((on . "<input type='checkbox' checked='checked' />")
	  (off . "<input type='checkbox' />")
	  (trans . "<input type='checkbox' />"))))
  "Alist of checkbox types.
The cdr of each entry is an alist list three checkbox types for
HTML export: `on', `off' and `trans'.

The choices are:
  `unicode' Unicode characters (HTML entities)
  `ascii'   ASCII characters
  `html'    HTML checkboxes

Note that only the ascii characters implement tri-state
checkboxes. The other two use the `off' checkbox for `trans'.")

(defcustom org-html-checkbox-type 'ascii
  "The type of checkboxes to use for HTML export.
See `org-html-checkbox-types' for for the values used for each
option."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type '(choice
	  (const :tag "ASCII characters" ascii)
	  (const :tag "Unicode characters" unicode)
	  (const :tag "HTML checkboxes" html)))

(defcustom org-html-metadata-timestamp-format "%Y-%m-%d %a %H:%M"
  "Format used for timestamps in preamble, postamble and metadata.
See `format-time-string' for more information on its components."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'string)

;;;; Template :: Mathjax

(defcustom org-html-mathjax-options
  '((path "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS_HTML" )
    (scale "100")
    (align "center")
    (font "TeX")
    (linebreaks "false")
    (autonumber "AMS")
    (indent "0em")
    (multlinewidth "85%")
    (tagindent ".8em")
    (tagside "right"))
  "Options for MathJax setup.

Alist of the following elements.  All values are strings.

path          The path to MathJax.
scale         Scaling with HTML-CSS, MathML and SVG output engines.
align         How to align display math: left, center, or right.
font          The font to use with HTML-CSS and SVG output.  As of MathJax 2.5
              the following values are understood: \"TeX\", \"STIX-Web\",
              \"Asana-Math\", \"Neo-Euler\", \"Gyre-Pagella\",
              \"Gyre-Termes\", and \"Latin-Modern\".
linebreaks    Let MathJax perform automatic linebreaks.  Valid values
              are \"true\" and \"false\".
indent        If align is not center, how far from the left/right side?
              Valid values are \"left\" and \"right\"
multlinewidth The width of the multline environment.
autonumber    How to number equations.  Valid values are \"None\",
              \"all\" and \"AMS Math\".
tagindent     The amount tags are indented.
tagside       Which side to show tags/labels on.  Valid values are
              \"left\" and \"right\"

You can also customize this for each buffer, using something like

#+HTML_MATHJAX: align: left indent: 5em tagside: left font: Neo-Euler

For further information about MathJax options, see the MathJax documentation:

  http://docs.mathjax.org/"
  :group 'org-export-html
  :package-version '(Org . "8.3")
  :type '(list :greedy t
	       (list :tag "path   (the path from where to load MathJax.js)"
		     (const :format "       " path) (string))
	       (list :tag "scale  (scaling for the displayed math)"
		     (const :format "       " scale) (string))
	       (list :tag "align  (alignment of displayed equations)"
		     (const :format "       " align) (string))
	       (list :tag "font (used to display math)"
		     (const :format "            " font)
		     (choice (const "TeX")
			     (const "STIX-Web")
			     (const "Asana-Math")
			     (const "Neo-Euler")
			     (const "Gyre-Pagella")
			     (const "Gyre-Termes")
			     (const "Latin-Modern")))
	       (list :tag "linebreaks (automatic line-breaking)"
		     (const :format "      " linebreaks)
		     (choice (const "true")
			     (const "false")))
	       (list :tag "autonumber (when should equations be numbered)"
		     (const :format "      " autonumber)
		     (choice (const "AMS")
			     (const "None")
			     (const "All")))
	       (list :tag "indent (indentation with left or right alignment)"
		     (const :format "       " indent) (string))
	       (list :tag "multlinewidth (width to use for the multline environment)"
		     (const :format "       " multlinewidth) (string))
	       (list :tag "tagindent (the indentation of tags from left or right)"
		     (const :format "     " tagindent) (string))
	       (list :tag "tagside (location of tags)"
		     (const :format "      " tagside)
		     (choice (const "left")
			     (const "right")))))

(defcustom org-html-mathjax-template
  "<script type=\"text/x-mathjax-config\">
    MathJax.Hub.Config({
        displayAlign: \"%ALIGN\",
        displayIndent: \"%INDENT\",

        \"HTML-CSS\": { scale: %SCALE,
                        linebreaks: { automatic: \"%LINEBREAKS\" },
                        webFont: \"%FONT\"
                       },
        SVG: {scale: %SCALE,
              linebreaks: { automatic: \"%LINEBREAKS\" },
              font: \"%FONT\"},
        NativeMML: {scale: %SCALE},
        TeX: { equationNumbers: {autoNumber: \"%AUTONUMBER\"},
               MultLineWidth: \"%MULTLINEWIDTH\",
               TagSide: \"%TAGSIDE\",
               TagIndent: \"%TAGINDENT\"
             }
});
</script>
<script type=\"text/javascript\"
        src=\"%PATH\"></script>"
  "The MathJax template.  See also `org-html-mathjax-options'."
  :group 'org-export-html
  :type 'string)

;;;; Template :: Postamble

(defcustom org-html-postamble 'auto
  "Non-nil means insert a postamble in HTML export.

When set to `auto', check against the
`org-export-with-author/email/creator/date' variables to set the
content of the postamble.  When set to a string, use this string
as the postamble.  When t, insert a string as defined by the
formatting string in `org-html-postamble-format'.

When set to a function, apply this function and insert the
returned string.  The function takes the property list of export
options as its only argument.

Setting :html-postamble in publishing projects will take
precedence over this variable."
  :group 'org-export-html
  :type '(choice (const :tag "No postamble" nil)
		 (const :tag "Auto postamble" auto)
		 (const :tag "Default formatting string" t)
		 (string :tag "Custom formatting string")
		 (function :tag "Function (must return a string)")))

(defcustom org-html-postamble-format
  '(("en" "<p class=\"author\">Author: %a (%e)</p>
<p class=\"date\">Date: %d</p>
<p class=\"creator\">%c</p>
<p class=\"validation\">%v</p>"))
  "Alist of languages and format strings for the HTML postamble.

The first element of each list is the language code, as used for
the LANGUAGE keyword.  See `org-export-default-language'.

The second element of each list is a format string to format the
postamble itself.  This format string can contain these elements:

  %t stands for the title.
  %s stands for the subtitle.
  %a stands for the author's name.
  %e stands for the author's email.
  %d stands for the date.
  %c will be replaced by `org-html-creator-string'.
  %v will be replaced by `org-html-validation-link'.
  %T will be replaced by the export time.
  %C will be replaced by the last modification time.

If you need to use a \"%\" character, you need to escape it
like that: \"%%\"."
  :group 'org-export-html
  :type '(repeat
	  (list (string :tag "Language")
		(string :tag "Format string"))))

(defcustom org-html-validation-link
  "<a href=\"http://validator.w3.org/check?uri=referer\">Validate</a>"
  "Link to HTML validation service."
  :group 'org-export-html
  :type 'string)

(defcustom org-html-creator-string
  (format "<a href=\"https://www.gnu.org/software/emacs/\">Emacs</a> %s (<a href=\"https://orgmode.org\">Org</a> mode %s)"
	  emacs-version
	  (if (fboundp 'org-version) (org-version) "unknown version"))
  "Information about the creator of the HTML document.
This option can also be set on with the CREATOR keyword."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type '(string :tag "Creator string"))

;;;; Template :: Preamble

(defcustom org-html-preamble t
  "Non-nil means insert a preamble in HTML export.

When t, insert a string as defined by the formatting string in
`org-html-preamble-format'.  When set to a string, use this
formatting string instead (see `org-html-postamble-format' for an
example of such a formatting string).

When set to a function, apply this function and insert the
returned string.  The function takes the property list of export
options as its only argument.

Setting :html-preamble in publishing projects will take
precedence over this variable."
  :group 'org-export-html
  :type '(choice (const :tag "No preamble" nil)
		 (const :tag "Default preamble" t)
		 (string :tag "Custom formatting string")
		 (function :tag "Function (must return a string)")))

(defcustom org-html-preamble-format '(("en" ""))
  "Alist of languages and format strings for the HTML preamble.

The first element of each list is the language code, as used for
the LANGUAGE keyword.  See `org-export-default-language'.

The second element of each list is a format string to format the
preamble itself.  This format string can contain these elements:

  %t stands for the title.
  %s stands for the subtitle.
  %a stands for the author's name.
  %e stands for the author's email.
  %d stands for the date.
  %c will be replaced by `org-html-creator-string'.
  %v will be replaced by `org-html-validation-link'.
  %T will be replaced by the export time.
  %C will be replaced by the last modification time.

If you need to use a \"%\" character, you need to escape it
like that: \"%%\".

See the default value of `org-html-postamble-format' for an
example."
  :group 'org-export-html
  :type '(repeat
	  (list (string :tag "Language")
		(string :tag "Format string"))))

(defcustom org-html-link-up ""
  "Where should the \"UP\" link of exported HTML pages lead?"
  :group 'org-export-html
  :type '(string :tag "File or URL"))

(defcustom org-html-link-home ""
  "Where should the \"HOME\" link of exported HTML pages lead?"
  :group 'org-export-html
  :type '(string :tag "File or URL"))

(defcustom org-html-link-use-abs-url nil
  "Should we prepend relative links with HTML_LINK_HOME?"
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.1")
  :type 'boolean)

(defcustom org-html-home/up-format
  "<div id=\"org-div-home-and-up\">
 <a accesskey=\"h\" href=\"%s\"> UP </a>
 |
 <a accesskey=\"H\" href=\"%s\"> HOME </a>
</div>"
  "Snippet used to insert the HOME and UP links.
This is a format string, the first %s will receive the UP link,
the second the HOME link.  If both `org-html-link-up' and
`org-html-link-home' are empty, the entire snippet will be
ignored."
  :group 'org-export-html
  :type 'string)

;;;; Template :: Scripts

(defcustom org-html-head-include-scripts t
  "Non-nil means include the JavaScript snippets in exported HTML files.
The actual script is defined in `org-html-scripts' and should
not be modified."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'boolean)

;;;; Template :: Styles

(defcustom org-html-head-include-default-style t
  "Non-nil means include the default style in exported HTML files.
The actual style is defined in `org-html-style-default' and
should not be modified.  Use `org-html-head' to use your own
style information."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'boolean)
;;;###autoload
(put 'org-html-head-include-default-style 'safe-local-variable 'booleanp)

(defcustom org-html-head ""
  "Org-wide head definitions for exported HTML files.

This variable can contain the full HTML structure to provide a
style, including the surrounding HTML tags.  You can consider
including definitions for the following classes: title, todo,
done, timestamp, timestamp-kwd, tag, target.

For example, a valid value would be:

   <style type=\"text/css\">
    /*<![CDATA[*/
      p { font-weight: normal; color: gray; }
      h1 { color: black; }
      .title { text-align: center; }
      .todo, .timestamp-kwd { color: red; }
      .done { color: green; }
    /*]]>*/
   </style>

If you want to refer to an external style, use something like

   <link rel=\"stylesheet\" type=\"text/css\" href=\"mystyles.css\" />

As the value of this option simply gets inserted into the HTML
<head> header, you can use it to add any arbitrary text to the
header.

You can set this on a per-file basis using #+HTML_HEAD:,
or for publication projects using the :html-head property."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'string)
;;;###autoload
(put 'org-html-head 'safe-local-variable 'stringp)

(defcustom org-html-head-extra ""
  "More head information to add in the HTML output.

You can set this on a per-file basis using #+HTML_HEAD_EXTRA:,
or for publication projects using the :html-head-extra property."
  :group 'org-export-html
  :version "24.4"
  :package-version '(Org . "8.0")
  :type 'string)
;;;###autoload
(put 'org-html-head-extra 'safe-local-variable 'stringp)

;;;; Template :: Viewport

(defcustom org-html-viewport '((width "device-width")
			       (initial-scale "1")
			       (minimum-scale "")
			       (maximum-scale "")
			       (user-scalable ""))
  "Viewport options for mobile-optimized sites.

The following values are recognized

width          Size of the viewport.
initial-scale  Zoom level when the page is first loaded.
minimum-scale  Minimum allowed zoom level.
maximum-scale  Maximum allowed zoom level.
user-scalable  Whether zoom can be changed.

The viewport meta tag is inserted if this variable is non-nil.

See the following site for a reference:
https://developer.mozilla.org/en-US/docs/Mozilla/Mobile/Viewport_meta_tag"
  :group 'org-export-html
  :version "26.1"
  :package-version '(Org . "8.3")
  :type '(choice (const :tag "Disable" nil)
		 (list :tag "Enable"
		       (list :tag "Width of viewport"
			     (const :format "             " width)
			     (choice (const :tag "unset" "")
				     (string)))
		       (list :tag "Initial scale"
			     (const :format "             " initial-scale)
			     (choice (const :tag "unset" "")
				     (string)))
		       (list :tag "Minimum scale/zoom"
			     (const :format "             " minimum-scale)
			     (choice (const :tag "unset" "")
				     (string)))
		       (list :tag "Maximum scale/zoom"
			     (const :format "             " maximum-scale)
			     (choice (const :tag "unset" "")
				     (string)))
		       (list :tag "User scalable/zoomable"
			     (const :format "             " user-scalable)
			     (choice (const :tag "unset" "")
				     (const "true")
				     (const "false"))))))

;; Handle source code blocks with Klipse

(defcustom org-html-klipsify-src nil
  "When non-nil, source code blocks are editable in exported presentation."
  :group 'org-export-html
  :package-version '(Org . "9.1")
  :type 'boolean)

(defcustom org-html-klipse-css
  "https://storage.googleapis.com/app.klipse.tech/css/codemirror.css"
  "Location of the codemirror CSS file for use with klipse."
  :group 'org-export-html
  :package-version '(Org . "9.1")
  :type 'string)

(defcustom org-html-klipse-js
  "https://storage.googleapis.com/app.klipse.tech/plugin_prod/js/klipse_plugin.min.js"
  "Location of the klipse javascript file."
  :group 'org-export-html
  :type 'string)

(defcustom org-html-klipse-selection-script
  "window.klipse_settings = {selector_eval_html: '.src-html',
                             selector_eval_js: '.src-js',
                             selector_eval_python_client: '.src-python',
                             selector_eval_scheme: '.src-scheme',
                             selector: '.src-clojure',
                             selector_eval_ruby: '.src-ruby'};"
  "Javascript snippet to activate klipse."
  :group 'org-export-html
  :package-version '(Org . "9.1")
  :type 'string)


;;;; Todos

(defcustom org-html-todo-kwd-class-prefix ""
  "Prefix to class names for TODO keywords.
Each TODO keyword gets a class given by the keyword itself, with this prefix.
The default prefix is empty because it is nice to just use the keyword
as a class name.  But if you get into conflicts with other, existing
CSS classes, then this prefix can be very useful."
  :group 'org-export-html
  :type 'string)


;;; Internal Functions

(defun org-html-xhtml-p (info)
  (let ((dt (downcase (plist-get info :html-doctype))))
    (string-match-p "xhtml" dt)))

(defun org-html-html5-p (info)
  (let ((dt (downcase (plist-get info :html-doctype))))
	(member dt '("html5" "xhtml5" "<!doctype html>"))))

(defun org-html--html5-fancy-p (info)
  "Non-nil when exporting to HTML5 with fancy elements.
INFO is the current state of the export process, as a plist."
  (and (plist-get info :html-html5-fancy)
       (org-html-html5-p info)))

(defun org-html-close-tag (tag attr info)
  "Return close-tag for string TAG.
ATTR specifies additional attributes.  INFO is a property list
containing current export state."
  (concat "<" tag
	  (org-string-nw-p (concat " " attr))
	  (if (org-html-xhtml-p info) " />" ">")))

(defun org-html-doctype (info)
  "Return correct HTML doctype tag.
INFO is a plist used as a communication channel.  Doctype tag is
extracted from `org-html-doctype-alist', or the literal value
of :html-doctype from INFO if :html-doctype is not found in the
alist."
  (let ((dt (plist-get info :html-doctype)))
    (or (cdr (assoc dt org-html-doctype-alist)) dt)))

(defun org-html--make-attribute-string (attributes)
  "Return a list of attributes, as a string.
ATTRIBUTES is a plist where values are either strings or nil.  An
attribute with a nil value will be omitted from the result."
  (let (output)
    (dolist (item attributes (mapconcat 'identity (nreverse output) " "))
      (cond ((null item) (pop output))
            ((symbolp item) (push (substring (symbol-name item) 1) output))
            (t (let ((key (car output))
                     (value (replace-regexp-in-string
                             "\"" "&quot;" (org-html-encode-plain-text item))))
                 (setcar output (format "%s=\"%s\"" key value))))))))

(defun org-html--wrap-image (contents info &optional caption label)
  "Wrap CONTENTS string within an appropriate environment for images.
INFO is a plist used as a communication channel.  When optional
arguments CAPTION and LABEL are given, use them for caption and
\"id\" attribute."
  (let ((html5-fancy (org-html--html5-fancy-p info)))
    (format (if html5-fancy "\n<figure%s>\n%s%s\n</figure>"
	      "\n<div%s class=\"figure\">\n%s%s\n</div>")
	    ;; ID.
	    (if (org-string-nw-p label) (format " id=\"%s\"" label) "")
	    ;; Contents.
	    (if html5-fancy contents (format "<p>%s</p>" contents))
	    ;; Caption.
	    (if (not (org-string-nw-p caption)) ""
	      (format (if html5-fancy "\n<figcaption>%s</figcaption>"
			"\n<p>%s</p>")
		      caption)))))

(defun org-html--format-image (source attributes info)
  "Return \"img\" tag with given SOURCE and ATTRIBUTES.
SOURCE is a string specifying the location of the image.
ATTRIBUTES is a plist, as returned by
`org-export-read-attribute'.  INFO is a plist used as
a communication channel."
  (if (string= "svg" (file-name-extension source))
      (org-html--svg-image source attributes info)
    (org-html-close-tag
     "img"
     (org-html--make-attribute-string
      (org-combine-plists
       (list :src source
	     :alt (if (string-match-p "^ltxpng/" source)
		      (org-html-encode-plain-text
		       (org-find-text-property-in-string 'org-latex-src source))
		    (file-name-nondirectory source)))
       attributes))
     info)))

(defun org-html--svg-image (source attributes info)
  "Return \"object\" embedding svg file SOURCE with given ATTRIBUTES.
INFO is a plist used as a communication channel.

The special attribute \"fallback\" can be used to specify a
fallback image file to use if the object embedding is not
supported.  CSS class \"org-svg\" is assigned as the class of the
object unless a different class is specified with an attribute."
  (let ((fallback (plist-get attributes :fallback))
	(attrs (org-html--make-attribute-string
		(org-combine-plists
                 ;; Remove fallback attribute, which is not meant to
                 ;; appear directly in the attributes string, and
                 ;; provide a default class if none is set.
                 '(:class "org-svg") attributes '(:fallback nil)))))
    (format "<object type=\"image/svg+xml\" data=\"%s\" %s>\n%s</object>"
	    source
	    attrs
	    (if fallback
		(org-html-close-tag
		 "img" (format "src=\"%s\" %s" fallback attrs) info)
	      "Sorry, your browser does not support SVG."))))

(defun org-html--textarea-block (element)
  "Transcode ELEMENT into a textarea block.
ELEMENT is either a source or an example block."
  (let* ((code (car (org-export-unravel-code element)))
	 (attr (org-export-read-attribute :attr_html element)))
    (format "<p>\n<textarea cols=\"%s\" rows=\"%s\">\n%s</textarea>\n</p>"
	    (or (plist-get attr :width) 80)
	    (or (plist-get attr :height) (org-count-lines code))
	    code)))

(defun org-html--has-caption-p (element &optional _info)
  "Non-nil when ELEMENT has a caption affiliated keyword.
INFO is a plist used as a communication channel.  This function
is meant to be used as a predicate for `org-export-get-ordinal' or
a value to `org-html-standalone-image-predicate'."
  (org-element-property :caption element))

;;;; Table

(defun org-html-htmlize-region-for-paste (beg end)
  "Convert the region between BEG and END to HTML, using htmlize.el.
This is much like `htmlize-region-for-paste', only that it uses
the settings define in the org-... variables."
  (let* ((htmlize-output-type org-html-htmlize-output-type)
	 (htmlize-css-name-prefix org-html-htmlize-font-prefix)
	 (htmlbuf (htmlize-region beg end)))
    (unwind-protect
	(with-current-buffer htmlbuf
	  (buffer-substring (plist-get htmlize-buffer-places 'content-start)
			    (plist-get htmlize-buffer-places 'content-end)))
      (kill-buffer htmlbuf))))

;;;###autoload
(defun org-html-htmlize-generate-css ()
  "Create the CSS for all font definitions in the current Emacs session.
Use this to create face definitions in your CSS style file that can then
be used by code snippets transformed by htmlize.
This command just produces a buffer that contains class definitions for all
faces used in the current Emacs session.  You can copy and paste the ones you
need into your CSS file.

If you then set `org-html-htmlize-output-type' to `css', calls
to the function `org-html-htmlize-region-for-paste' will
produce code that uses these same face definitions."
  (interactive)
  (unless (require 'htmlize nil t)
    (error "htmlize library missing.  Aborting"))
  (and (get-buffer "*html*") (kill-buffer "*html*"))
  (with-temp-buffer
    (let ((fl (face-list))
	  (htmlize-css-name-prefix "org-")
	  (htmlize-output-type 'css)
	  f i)
      (while (setq f (pop fl)
		   i (and f (face-attribute f :inherit)))
	(when (and (symbolp f) (or (not i) (not (listp i))))
	  (insert (org-add-props (copy-sequence "1") nil 'face f))))
      (htmlize-region (point-min) (point-max))))
  (pop-to-buffer-same-window "*html*")
  (goto-char (point-min))
  (when (re-search-forward "<style" nil t)
    (delete-region (point-min) (match-beginning 0)))
  (when (re-search-forward "</style>" nil t)
    (delete-region (1+ (match-end 0)) (point-max)))
  (beginning-of-line 1)
  (when (looking-at " +") (replace-match ""))
  (goto-char (point-min)))

(defun org-html--make-string (n string)
  "Build a string by concatenating N times STRING."
  (let (out) (dotimes (_ n out) (setq out (concat string out)))))

(defun org-html-fix-class-name (kwd)	; audit callers of this function
  "Turn todo keyword KWD into a valid class name.
Replaces invalid characters with \"_\"."
  (replace-regexp-in-string "[^a-zA-Z0-9_]" "_" kwd nil t))

(defun org-html-footnote-section (info)
  "Format the footnote section.
INFO is a plist used as a communication channel."
  (pcase (org-export-collect-footnote-definitions info)
    (`nil nil)
    (definitions
      (format
       (plist-get info :html-footnotes-section)
       (org-html--translate "Footnotes" info)
       (format
	"\n%s\n"
	(mapconcat
	 (lambda (definition)
	   (pcase definition
	     (`(,n ,_ ,def)
	      ;; `org-export-collect-footnote-definitions' can return
	      ;; two kinds of footnote definitions: inline and blocks.
	      ;; Since this should not make any difference in the HTML
	      ;; output, we wrap the inline definitions within
	      ;; a "footpara" class paragraph.
	      (let ((inline? (not (org-element-map def org-element-all-elements
				    #'identity nil t)))
		    (anchor (org-html--anchor
			     (format "fn.%d" n)
			     n
			     (format " class=\"footnum\" href=\"#fnr.%d\"" n)
			     info))
		    (contents (org-trim (org-export-data def info))))
		(format "<div class=\"footdef\">%s %s</div>\n"
			(format (plist-get info :html-footnote-format) anchor)
			(format "<div class=\"footpara\">%s</div>"
				(if (not inline?) contents
				  (format "<p class=\"footpara\">%s</p>"
					  contents))))))))
	 definitions
	 "\n"))))))


;;; Template

(defun org-html--build-meta-info (info)
  "Return meta tags for exported document.
INFO is a plist used as a communication channel."
  (let* ((protect-string
          (lambda (str)
            (replace-regexp-in-string
             "\"" "&quot;" (org-html-encode-plain-text str))))
         (title (org-export-data (plist-get info :title) info))
         ;; Set title to an invisible character instead of leaving it
         ;; empty, which is invalid.
         (title (if (org-string-nw-p title) title "&lrm;"))
         (author (and (plist-get info :with-author)
                      (let ((auth (plist-get info :author)))
                        (and auth
                             ;; Return raw Org syntax, skipping non
                             ;; exportable objects.
                             (org-element-interpret-data
                              (org-element-map auth
                                  (cons 'plain-text org-element-all-objects)
                                'identity info))))))
         (description (plist-get info :description))
         (keywords (plist-get info :keywords))
         (charset (or (and org-html-coding-system
                           (fboundp 'coding-system-get)
                           (coding-system-get org-html-coding-system
                                              'mime-charset))
                      "iso-8859-1")))
    (concat
     (when (plist-get info :time-stamp-file)
       (format-time-string
	(concat "<!-- "
		(plist-get info :html-metadata-timestamp-format)
		" -->\n")))
     (format
      (if (org-html-html5-p info)
	  (org-html-close-tag "meta" "charset=\"%s\"" info)
	(org-html-close-tag
	 "meta" "http-equiv=\"Content-Type\" content=\"text/html;charset=%s\""
	 info))
      charset) "\n"
     (let ((viewport-options
	    (cl-remove-if-not (lambda (cell) (org-string-nw-p (cadr cell)))
			       (plist-get info :html-viewport))))
       (and viewport-options
	    (concat
	     (org-html-close-tag
	      "meta"
	      (format "name=\"viewport\" content=\"%s\""
		      (mapconcat
		       (lambda (elm) (format "%s=%s" (car elm) (cadr elm)))
		       viewport-options ", "))
	      info)
	     "\n")))
     (format "<title>%s</title>\n" title)
     (org-html-close-tag "meta" "name=\"generator\" content=\"Org mode\"" info)
     "\n"
     (and (org-string-nw-p author)
	  (concat
	   (org-html-close-tag "meta"
			       (format "name=\"author\" content=\"%s\""
				       (funcall protect-string author))
			       info)
	   "\n"))
     (and (org-string-nw-p description)
	  (concat
	   (org-html-close-tag "meta"
			       (format "name=\"description\" content=\"%s\"\n"
				       (funcall protect-string description))
			       info)
	   "\n"))
     (and (org-string-nw-p keywords)
	  (concat
	   (org-html-close-tag "meta"
			       (format "name=\"keywords\" content=\"%s\""
				       (funcall protect-string keywords))
			       info)
	   "\n")))))

(defun org-html--build-head (info)
  "Return information for the <head>..</head> of the HTML output.
INFO is a plist used as a communication channel."
  (org-element-normalize-string
   (concat
    (when (plist-get info :html-head-include-default-style)
      (org-element-normalize-string org-html-style-default))
    (org-element-normalize-string (plist-get info :html-head))
    (org-element-normalize-string (plist-get info :html-head-extra))
    (when (and (plist-get info :html-htmlized-css-url)
	       (eq org-html-htmlize-output-type 'css))
      (org-html-close-tag "link"
			  (format "rel=\"stylesheet\" href=\"%s\" type=\"text/css\""
				  (plist-get info :html-htmlized-css-url))
			  info))
    (when (plist-get info :html-head-include-scripts) org-html-scripts))))

(defun org-html--build-mathjax-config (info)
  "Insert the user setup into the mathjax template.
INFO is a plist used as a communication channel."
  (when (and (memq (plist-get info :with-latex) '(mathjax t))
	     (org-element-map (plist-get info :parse-tree)
		 '(latex-fragment latex-environment) #'identity info t nil t))
    (let ((template (plist-get info :html-mathjax-template))
	  (options (plist-get info :html-mathjax-options))
	  (in-buffer (or (plist-get info :html-mathjax) "")))
      (dolist (e options (org-element-normalize-string template))
	(let ((name (car e))
	      (val (nth 1 e)))
	  (when (string-match (concat "\\<" (symbol-name name) ":") in-buffer)
	    (setq val
		  (car (read-from-string (substring in-buffer (match-end 0))))))
	  (unless (stringp val) (setq val (format "%s" val)))
	  (while (string-match (concat "%" (upcase (symbol-name name)))
			       template)
	    (setq template (replace-match val t t template))))))))

(defun org-html-format-spec (info)
  "Return format specification for preamble and postamble.
INFO is a plist used as a communication channel."
  (let ((timestamp-format (plist-get info :html-metadata-timestamp-format)))
    `((?t . ,(org-export-data (plist-get info :title) info))
      (?s . ,(org-export-data (plist-get info :subtitle) info))
      (?d . ,(org-export-data (org-export-get-date info timestamp-format)
			      info))
      (?T . ,(format-time-string timestamp-format))
      (?a . ,(org-export-data (plist-get info :author) info))
      (?e . ,(mapconcat
	      (lambda (e) (format "<a href=\"mailto:%s\">%s</a>" e e))
	      (split-string (plist-get info :email)  ",+ *")
	      ", "))
      (?c . ,(plist-get info :creator))
      (?C . ,(let ((file (plist-get info :input-file)))
	       (format-time-string timestamp-format
				   (and file (file-attribute-modification-time
					      (file-attributes file))))))
      (?v . ,(or (plist-get info :html-validation-link) "")))))

(defun org-html--build-pre/postamble (type info)
  "Return document preamble or postamble as a string, or nil.
TYPE is either `preamble' or `postamble', INFO is a plist used as a
communication channel."
  (let ((section (plist-get info (intern (format ":html-%s" type))))
	(spec (org-html-format-spec info)))
    (when section
      (let ((section-contents
	     (if (functionp section) (funcall section info)
	       (cond
		((stringp section) (format-spec section spec))
		((eq section 'auto)
		 (let ((date (cdr (assq ?d spec)))
		       (author (cdr (assq ?a spec)))
		       (email (cdr (assq ?e spec)))
		       (creator (cdr (assq ?c spec)))
		       (validation-link (cdr (assq ?v spec))))
		   (concat
		    (and (plist-get info :with-date)
			 (org-string-nw-p date)
			 (format "<p class=\"date\">%s: %s</p>\n"
				 (org-html--translate "Date" info)
				 date))
		    (and (plist-get info :with-author)
			 (org-string-nw-p author)
			 (format "<p class=\"author\">%s: %s</p>\n"
				 (org-html--translate "Author" info)
				 author))
		    (and (plist-get info :with-email)
			 (org-string-nw-p email)
			 (format "<p class=\"email\">%s: %s</p>\n"
				 (org-html--translate "Email" info)
				 email))
		    (and (plist-get info :time-stamp-file)
			 (format
			  "<p class=\"date\">%s: %s</p>\n"
			  (org-html--translate "Created" info)
			  (format-time-string
			   (plist-get info :html-metadata-timestamp-format))))
		    (and (plist-get info :with-creator)
			 (org-string-nw-p creator)
			 (format "<p class=\"creator\">%s</p>\n" creator))
		    (and (org-string-nw-p validation-link)
			 (format "<p class=\"validation\">%s</p>\n"
				 validation-link)))))
		(t
		 (let ((formats (plist-get info (if (eq type 'preamble)
						    :html-preamble-format
						  :html-postamble-format)))
		       (language (plist-get info :language)))
		   (format-spec
		    (cadr (or (assoc-string language formats t)
			      (assoc-string "en" formats t)))
		    spec)))))))
	(let ((div (assq type (plist-get info :html-divs))))
	  (when (org-string-nw-p section-contents)
	    (concat
	     (format "<%s id=\"%s\" class=\"%s\">\n"
		     (nth 1 div)
		     (nth 2 div)
		     org-html--pre/postamble-class)
	     (org-element-normalize-string section-contents)
	     (format "</%s>\n" (nth 1 div)))))))))

(defun org-html-inner-template (contents info)
  "Return body of document string after HTML conversion.
CONTENTS is the transcoded contents string.  INFO is a plist
holding export options."
  (concat
   ;; Table of contents.
   (let ((depth (plist-get info :with-toc)))
     (when depth (org-html-toc depth info)))
   ;; Document contents.
   contents
   ;; Footnotes section.
   (org-html-footnote-section info)))

(defun org-html-template (contents info)
  "Return complete document string after HTML conversion.
CONTENTS is the transcoded contents string.  INFO is a plist
holding export options."
  (concat
   (when (and (not (org-html-html5-p info)) (org-html-xhtml-p info))
     (let* ((xml-declaration (plist-get info :html-xml-declaration))
	    (decl (or (and (stringp xml-declaration) xml-declaration)
		      (cdr (assoc (plist-get info :html-extension)
				  xml-declaration))
		      (cdr (assoc "html" xml-declaration))
		      "")))
       (when (not (or (not decl) (string= "" decl)))
	 (format "%s\n"
		 (format decl
			 (or (and org-html-coding-system
				  (fboundp 'coding-system-get)
				  (coding-system-get org-html-coding-system 'mime-charset))
			     "iso-8859-1"))))))
   (org-html-doctype info)
   "\n"
   (concat "<html"
	   (cond ((org-html-xhtml-p info)
		  (format
		   " xmlns=\"http://www.w3.org/1999/xhtml\" lang=\"%s\" xml:lang=\"%s\""
		   (plist-get info :language) (plist-get info :language)))
		 ((org-html-html5-p info)
		  (format " lang=\"%s\"" (plist-get info :language))))
	   ">\n")
   "<head>\n"
   (org-html--build-meta-info info)
   (org-html--build-head info)
   (org-html--build-mathjax-config info)
   "</head>\n"
   "<body>\n"
   (let ((link-up (org-trim (plist-get info :html-link-up)))
	 (link-home (org-trim (plist-get info :html-link-home))))
     (unless (and (string= link-up "") (string= link-home ""))
       (format (plist-get info :html-home/up-format)
	       (or link-up link-home)
	       (or link-home link-up))))
   ;; Preamble.
   (org-html--build-pre/postamble 'preamble info)
   ;; Document contents.
   (let ((div (assq 'content (plist-get info :html-divs))))
     (format "<%s id=\"%s\">\n" (nth 1 div) (nth 2 div)))
   ;; Document title.
   (when (plist-get info :with-title)
     (let ((title (and (plist-get info :with-title)
		       (plist-get info :title)))
	   (subtitle (plist-get info :subtitle))
	   (html5-fancy (org-html--html5-fancy-p info)))
       (when title
	 (format
	  (if html5-fancy
	      "<header>\n<h1 class=\"title\">%s</h1>\n%s</header>"
	    "<h1 class=\"title\">%s%s</h1>\n")
	  (org-export-data title info)
	  (if subtitle
	      (format
	       (if html5-fancy
		   "<p class=\"subtitle\">%s</p>\n"
		 (concat "\n" (org-html-close-tag "br" nil info) "\n"
			 "<span class=\"subtitle\">%s</span>\n"))
	       (org-export-data subtitle info))
	    "")))))
   contents
   (format "</%s>\n" (nth 1 (assq 'content (plist-get info :html-divs))))
   ;; Postamble.
   (org-html--build-pre/postamble 'postamble info)
   ;; Possibly use the Klipse library live code blocks.
   (when (plist-get info :html-klipsify-src)
     (concat "<script>" (plist-get info :html-klipse-selection-script)
	     "</script><script src=\""
	     org-html-klipse-js
	     "\"></script><link rel=\"stylesheet\" type=\"text/css\" href=\""
	     org-html-klipse-css "\"/>"))
   ;; Closing document.
   "</body>\n</html>"))

(defun org-html--translate (s info)
  "Translate string S according to specified language.
INFO is a plist used as a communication channel."
  (org-export-translate s :html info))

;;;; Anchor

(defun org-html--anchor (id desc attributes info)
  "Format a HTML anchor."
  (let* ((name (and (plist-get info :html-allow-name-attribute-in-anchors) id))
	 (attributes (concat (and id (format " id=\"%s\"" id))
			     (and name (format " name=\"%s\"" name))
			     attributes)))
    (format "<a%s>%s</a>" attributes (or desc ""))))

;;;; Todo

(defun org-html--todo (todo info)
  "Format TODO keywords into HTML."
  (when todo
    (format "<span class=\"%s %s%s\">%s</span>"
	    (if (member todo org-done-keywords) "done" "todo")
	    (or (plist-get info :html-todo-kwd-class-prefix) "")
	    (org-html-fix-class-name todo)
	    todo)))

;;;; Priority

(defun org-html--priority (priority _info)
  "Format a priority into HTML.
PRIORITY is the character code of the priority or nil.  INFO is
a plist containing export options."
  (and priority (format "<span class=\"priority\">[%c]</span>" priority)))

;;;; Tags

(defun org-html--tags (tags info)
  "Format TAGS into HTML.
INFO is a plist containing export options."
  (when tags
    (format "<span class=\"tag\">%s</span>"
	    (mapconcat
	     (lambda (tag)
	       (format "<span class=\"%s\">%s</span>"
		       (concat (plist-get info :html-tag-class-prefix)
			       (org-html-fix-class-name tag))
		       tag))
	     tags "&#xa0;"))))

;;;; Src Code

(defun org-html-fontify-code (code lang)
  "Color CODE with htmlize library.
CODE is a string representing the source code to colorize.  LANG
is the language used for CODE, as a string, or nil."
  (when code
    (cond
     ;; No language.  Possibly an example block.
     ((not lang) (org-html-encode-plain-text code))
     ;; Plain text explicitly set.
     ((not org-html-htmlize-output-type) (org-html-encode-plain-text code))
     ;; No htmlize library or an inferior version of htmlize.
     ((not (progn (require 'htmlize nil t)
		  (fboundp 'htmlize-region-for-paste)))
      ;; Emit a warning.
      (message "Cannot fontify source block (htmlize.el >= 1.34 required)")
      (org-html-encode-plain-text code))
     (t
      ;; Map language
      (setq lang (or (assoc-default lang org-src-lang-modes) lang))
      (let* ((lang-mode (and lang (intern (format "%s-mode" lang)))))
	(cond
	 ;; Case 1: Language is not associated with any Emacs mode
	 ((not (functionp lang-mode))
	  (org-html-encode-plain-text code))
	 ;; Case 2: Default.  Fontify code.
	 (t
	  ;; htmlize
	  (setq code
		(let ((output-type org-html-htmlize-output-type)
		      (font-prefix org-html-htmlize-font-prefix))
		  (with-temp-buffer
		    ;; Switch to language-specific mode.
		    (funcall lang-mode)
		    (insert code)
		    ;; Fontify buffer.
		    (org-font-lock-ensure)
		    ;; Remove formatting on newline characters.
		    (save-excursion
		      (let ((beg (point-min))
			    (end (point-max)))
			(goto-char beg)
			(while (progn (end-of-line) (< (point) end))
			  (put-text-property (point) (1+ (point)) 'face nil)
			  (forward-char 1))))
		    (org-src-mode)
		    (set-buffer-modified-p nil)
		    ;; Htmlize region.
		    (let ((org-html-htmlize-output-type output-type)
			  (org-html-htmlize-font-prefix font-prefix))
		      (org-html-htmlize-region-for-paste
		       (point-min) (point-max))))))
	  ;; Strip any enclosing <pre></pre> tags.
	  (let* ((beg (and (string-match "\\`<pre[^>]*>\n?" code) (match-end 0)))
		 (end (and beg (string-match "</pre>\\'" code))))
	    (if (and beg end) (substring code beg end) code)))))))))

(defun org-html-do-format-code
  (code &optional lang refs retain-labels num-start)
  "Format CODE string as source code.
Optional arguments LANG, REFS, RETAIN-LABELS and NUM-START are,
respectively, the language of the source code, as a string, an
alist between line numbers and references (as returned by
`org-export-unravel-code'), a boolean specifying if labels should
appear in the source code, and the number associated to the first
line of code."
  (let* ((code-lines (split-string code "\n"))
	 (code-length (length code-lines))
	 (num-fmt
	  (and num-start
	       (format "%%%ds: "
		       (length (number-to-string (+ code-length num-start))))))
	 (code (org-html-fontify-code code lang)))
    (org-export-format-code
     code
     (lambda (loc line-num ref)
       (setq loc
	     (concat
	      ;; Add line number, if needed.
	      (when num-start
		(format "<span class=\"linenr\">%s</span>"
			(format num-fmt line-num)))
	      ;; Transcoded src line.
	      loc
	      ;; Add label, if needed.
	      (when (and ref retain-labels) (format " (%s)" ref))))
       ;; Mark transcoded line as an anchor, if needed.
       (if (not ref) loc
	 (format "<span id=\"coderef-%s\" class=\"coderef-off\">%s</span>"
		 ref loc)))
     num-start refs)))

(defun org-html-format-code (element info)
  "Format contents of ELEMENT as source code.
ELEMENT is either an example or a source block.  INFO is a plist
used as a communication channel."
  (let* ((lang (org-element-property :language element))
	 ;; Extract code and references.
	 (code-info (org-export-unravel-code element))
	 (code (car code-info))
	 (refs (cdr code-info))
	 ;; Does the source block contain labels?
	 (retain-labels (org-element-property :retain-labels element))
	 ;; Does it have line numbers?
	 (num-start (org-export-get-loc element info)))
    (org-html-do-format-code code lang refs retain-labels num-start)))


;;; Tables of Contents

(defun org-html-toc (depth info &optional scope)
  "Build a table of contents.
DEPTH is an integer specifying the depth of the table.  INFO is
a plist used as a communication channel.  Optional argument SCOPE
is an element defining the scope of the table.  Return the table
of contents as a string, or nil if it is empty."
  (let ((toc-entries
	 (mapcar (lambda (headline)
		   (cons (org-html--format-toc-headline headline info)
			 (org-export-get-relative-level headline info)))
		 (org-export-collect-headlines info depth scope))))
    (when toc-entries
      (let ((toc (concat "<div id=\"text-table-of-contents\">"
			 (org-html--toc-text toc-entries)
			 "</div>\n")))
	(if scope toc
	  (let ((outer-tag (if (org-html--html5-fancy-p info)
			       "nav"
			     "div")))
	    (concat (format "<%s id=\"table-of-contents\">\n" outer-tag)
		    (let ((top-level (plist-get info :html-toplevel-hlevel)))
		      (format "<h%d>%s</h%d>\n"
			      top-level
			      (org-html--translate "Table of Contents" info)
			      top-level))
		    toc
		    (format "</%s>\n" outer-tag))))))))

(defun org-html--toc-text (toc-entries)
  "Return innards of a table of contents, as a string.
TOC-ENTRIES is an alist where key is an entry title, as a string,
and value is its relative level, as an integer."
  (let* ((prev-level (1- (cdar toc-entries)))
	 (start-level prev-level))
    (concat
     (mapconcat
      (lambda (entry)
	(let ((headline (car entry))
	      (level (cdr entry)))
	  (concat
	   (let* ((cnt (- level prev-level))
		  (times (if (> cnt 0) (1- cnt) (- cnt))))
	     (setq prev-level level)
	     (concat
	      (org-html--make-string
	       times (cond ((> cnt 0) "\n<ul>\n<li>")
			   ((< cnt 0) "</li>\n</ul>\n")))
	      (if (> cnt 0) "\n<ul>\n<li>" "</li>\n<li>")))
	   headline)))
      toc-entries "")
     (org-html--make-string (- prev-level start-level) "</li>\n</ul>\n"))))

(defun org-html--format-toc-headline (headline info)
  "Return an appropriate table of contents entry for HEADLINE.
INFO is a plist used as a communication channel."
  (let* ((headline-number (org-export-get-headline-number headline info))
	 (todo (and (plist-get info :with-todo-keywords)
		    (let ((todo (org-element-property :todo-keyword headline)))
		      (and todo (org-export-data todo info)))))
	 (todo-type (and todo (org-element-property :todo-type headline)))
	 (priority (and (plist-get info :with-priority)
			(org-element-property :priority headline)))
	 (text (org-export-data-with-backend
		(org-export-get-alt-title headline info)
		(org-export-toc-entry-backend 'html)
		info))
	 (tags (and (eq (plist-get info :with-tags) t)
		    (org-export-get-tags headline info))))
    (format "<a href=\"#%s\">%s</a>"
	    ;; Label.
	    (or (org-element-property :CUSTOM_ID headline)
		(org-export-get-reference headline info))
	    ;; Body.
	    (concat
	     (and (not (org-export-low-level-p headline info))
		  (org-export-numbered-headline-p headline info)
		  (concat (mapconcat #'number-to-string headline-number ".")
			  ". "))
	     (apply (plist-get info :html-format-headline-function)
		    todo todo-type priority text tags :section-number nil)))))

(defun org-html-list-of-listings (info)
  "Build a list of listings.
INFO is a plist used as a communication channel.  Return the list
of listings as a string, or nil if it is empty."
  (let ((lol-entries (org-export-collect-listings info)))
    (when lol-entries
      (concat "<div id=\"list-of-listings\">\n"
	      (let ((top-level (plist-get info :html-toplevel-hlevel)))
		(format "<h%d>%s</h%d>\n"
			top-level
			(org-html--translate "List of Listings" info)
			top-level))
	      "<div id=\"text-list-of-listings\">\n<ul>\n"
	      (let ((count 0)
		    (initial-fmt (format "<span class=\"listing-number\">%s</span>"
					 (org-html--translate "Listing %d:" info))))
		(mapconcat
		 (lambda (entry)
		   (let ((label (and (org-element-property :name entry)
				     (org-export-get-reference entry info)))
			 (title (org-trim
				 (org-export-data
				  (or (org-export-get-caption entry t)
				      (org-export-get-caption entry))
				  info))))
		     (concat
		      "<li>"
		      (if (not label)
			  (concat (format initial-fmt (cl-incf count))
				  " "
				  title)
			(format "<a href=\"#%s\">%s %s</a>"
				label
				(format initial-fmt (cl-incf count))
				title))
		      "</li>")))
		 lol-entries "\n"))
	      "\n</ul>\n</div>\n</div>"))))

(defun org-html-list-of-tables (info)
  "Build a list of tables.
INFO is a plist used as a communication channel.  Return the list
of tables as a string, or nil if it is empty."
  (let ((lol-entries (org-export-collect-tables info)))
    (when lol-entries
      (concat "<div id=\"list-of-tables\">\n"
	      (let ((top-level (plist-get info :html-toplevel-hlevel)))
		(format "<h%d>%s</h%d>\n"
			top-level
			(org-html--translate "List of Tables" info)
			top-level))
	      "<div id=\"text-list-of-tables\">\n<ul>\n"
	      (let ((count 0)
		    (initial-fmt (format "<span class=\"table-number\">%s</span>"
					 (org-html--translate "Table %d:" info))))
		(mapconcat
		 (lambda (entry)
		   (let ((label (and (org-element-property :name entry)
				     (org-export-get-reference entry info)))
			 (title (org-trim
				 (org-export-data
				  (or (org-export-get-caption entry t)
				      (org-export-get-caption entry))
				  info))))
		     (concat
		      "<li>"
		      (if (not label)
			  (concat (format initial-fmt (cl-incf count))
				  " "
				  title)
			(format "<a href=\"#%s\">%s %s</a>"
				label
				(format initial-fmt (cl-incf count))
				title))
		      "</li>")))
		 lol-entries "\n"))
	      "\n</ul>\n</div>\n</div>"))))


;;; Transcode Functions

;;;; Bold

(defun org-html-bold (_bold contents info)
  "Transcode BOLD from Org to HTML.
CONTENTS is the text with bold markup.  INFO is a plist holding
contextual information."
  (format (or (cdr (assq 'bold (plist-get info :html-text-markup-alist))) "%s")
	  contents))

;;;; Center Block

(defun org-html-center-block (_center-block contents _info)
  "Transcode a CENTER-BLOCK element from Org to HTML.
CONTENTS holds the contents of the block.  INFO is a plist
holding contextual information."
  (format "<div class=\"org-center\">\n%s</div>" contents))

;;;; Clock

(defun org-html-clock (clock _contents _info)
  "Transcode a CLOCK element from Org to HTML.
CONTENTS is nil.  INFO is a plist used as a communication
channel."
  (format "<p>
<span class=\"timestamp-wrapper\">
<span class=\"timestamp-kwd\">%s</span> <span class=\"timestamp\">%s</span>%s
</span>
</p>"
	  org-clock-string
	  (org-timestamp-translate (org-element-property :value clock))
	  (let ((time (org-element-property :duration clock)))
	    (and time (format " <span class=\"timestamp\">(%s)</span>" time)))))

;;;; Code

(defun org-html-code (code _contents info)
  "Transcode CODE from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual
information."
  (format (or (cdr (assq 'code (plist-get info :html-text-markup-alist))) "%s")
	  (org-html-encode-plain-text (org-element-property :value code))))

;;;; Drawer

(defun org-html-drawer (drawer contents info)
  "Transcode a DRAWER element from Org to HTML.
CONTENTS holds the contents of the block.  INFO is a plist
holding contextual information."
  (funcall (plist-get info :html-format-drawer-function)
	   (org-element-property :drawer-name drawer)
	   contents))

;;;; Dynamic Block

(defun org-html-dynamic-block (_dynamic-block contents _info)
  "Transcode a DYNAMIC-BLOCK element from Org to HTML.
CONTENTS holds the contents of the block.  INFO is a plist
holding contextual information.  See `org-export-data'."
  contents)

;;;; Entity

(defun org-html-entity (entity _contents _info)
  "Transcode an ENTITY object from Org to HTML.
CONTENTS are the definition itself.  INFO is a plist holding
contextual information."
  (org-element-property :html entity))

;;;; Example Block

(defun org-html-example-block (example-block _contents info)
  "Transcode a EXAMPLE-BLOCK element from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual
information."
  (let ((attributes (org-export-read-attribute :attr_html example-block)))
    (if (plist-get attributes :textarea)
	(org-html--textarea-block example-block)
      (format "<pre class=\"example\"%s>\n%s</pre>"
	      (let* ((name (org-element-property :name example-block))
		     (a (org-html--make-attribute-string
			 (if (or (not name) (plist-member attributes :id))
			     attributes
			   (plist-put attributes :id name)))))
		(if (org-string-nw-p a) (concat " " a) ""))
	      (org-html-format-code example-block info)))))

;;;; Export Snippet

(defun org-html-export-snippet (export-snippet _contents _info)
  "Transcode a EXPORT-SNIPPET object from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual
information."
  (when (eq (org-export-snippet-backend export-snippet) 'html)
    (org-element-property :value export-snippet)))

;;;; Export Block

(defun org-html-export-block (export-block _contents _info)
  "Transcode a EXPORT-BLOCK element from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (when (string= (org-element-property :type export-block) "HTML")
    (org-remove-indentation (org-element-property :value export-block))))

;;;; Fixed Width

(defun org-html-fixed-width (fixed-width _contents _info)
  "Transcode a FIXED-WIDTH element from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (format "<pre class=\"example\">\n%s</pre>"
	  (org-html-do-format-code
	   (org-remove-indentation
	    (org-element-property :value fixed-width)))))

;;;; Footnote Reference

(defun org-html-footnote-reference (footnote-reference _contents info)
  "Transcode a FOOTNOTE-REFERENCE element from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (concat
   ;; Insert separator between two footnotes in a row.
   (let ((prev (org-export-get-previous-element footnote-reference info)))
     (when (eq (org-element-type prev) 'footnote-reference)
       (plist-get info :html-footnote-separator)))
   (let* ((n (org-export-get-footnote-number footnote-reference info))
	  (id (format "fnr.%d%s"
		      n
		      (if (org-export-footnote-first-reference-p
			   footnote-reference info)
			  ""
			".100"))))
     (format
      (plist-get info :html-footnote-format)
      (org-html--anchor
       id n (format " class=\"footref\" href=\"#fn.%d\"" n) info)))))

;;;; Headline

(defun org-html-headline (headline contents info)
  "Transcode a HEADLINE element from Org to HTML.
CONTENTS holds the contents of the headline.  INFO is a plist
holding contextual information."
  (unless (org-element-property :footnote-section-p headline)
    (let* ((numberedp (org-export-numbered-headline-p headline info))
           (numbers (org-export-get-headline-number headline info))
           (level (+ (org-export-get-relative-level headline info)
                     (1- (plist-get info :html-toplevel-hlevel))))
           (todo (and (plist-get info :with-todo-keywords)
                      (let ((todo (org-element-property :todo-keyword headline)))
                        (and todo (org-export-data todo info)))))
           (todo-type (and todo (org-element-property :todo-type headline)))
           (priority (and (plist-get info :with-priority)
                          (org-element-property :priority headline)))
           (text (org-export-data (org-element-property :title headline) info))
           (tags (and (plist-get info :with-tags)
                      (org-export-get-tags headline info)))
           (full-text (funcall (plist-get info :html-format-headline-function)
                               todo todo-type priority text tags info))
           (contents (or contents ""))
	   (id (or (org-element-property :CUSTOM_ID headline)
		   (org-export-get-reference headline info)))
	   (formatted-text
	    (if (plist-get info :html-self-link-headlines)
		(format "<a href=\"#%s\">%s</a>" id full-text)
	      full-text)))
      (if (org-export-low-level-p headline info)
          ;; This is a deep sub-tree: export it as a list item.
          (let* ((html-type (if numberedp "ol" "ul")))
	    (concat
	     (and (org-export-first-sibling-p headline info)
		  (apply #'format "<%s class=\"org-%s\">\n"
			 (make-list 2 html-type)))
	     (org-html-format-list-item
	      contents (if numberedp 'ordered 'unordered)
	      nil info nil
	      (concat (org-html--anchor id nil nil info) formatted-text)) "\n"
	     (and (org-export-last-sibling-p headline info)
		  (format "</%s>\n" html-type))))
	;; Standard headline.  Export it as a section.
        (let ((extra-class
	       (org-element-property :HTML_CONTAINER_CLASS headline))
	      (headline-class
	       (org-element-property :HTML_HEADLINE_CLASS headline))
              (first-content (car (org-element-contents headline))))
          (format "<%s id=\"%s\" class=\"%s\">%s%s</%s>\n"
                  (org-html--container headline info)
                  (concat "outline-container-"
			  (org-export-get-reference headline info))
                  (concat (format "outline-%d" level)
                          (and extra-class " ")
                          extra-class)
                  (format "\n<h%d id=\"%s\"%s>%s</h%d>\n"
                          level
                          id
			  (if (not headline-class) ""
			    (format " class=\"%s\"" headline-class))
                          (concat
                           (and numberedp
                                (format
                                 "<span class=\"section-number-%d\">%s</span> "
                                 level
                                 (mapconcat #'number-to-string numbers ".")))
                           formatted-text)
                          level)
                  ;; When there is no section, pretend there is an
                  ;; empty one to get the correct <div
                  ;; class="outline-...> which is needed by
                  ;; `org-info.js'.
                  (if (eq (org-element-type first-content) 'section) contents
                    (concat (org-html-section first-content "" info) contents))
                  (org-html--container headline info)))))))

(defun org-html-format-headline-default-function
    (todo _todo-type priority text tags info)
  "Default format function for a headline.
See `org-html-format-headline-function' for details."
  (let ((todo (org-html--todo todo info))
	(priority (org-html--priority priority info))
	(tags (org-html--tags tags info)))
    (concat todo (and todo " ")
	    priority (and priority " ")
	    text
	    (and tags "&#xa0;&#xa0;&#xa0;") tags)))

(defun org-html--container (headline info)
  (or (org-element-property :HTML_CONTAINER headline)
      (if (= 1 (org-export-get-relative-level headline info))
	  (plist-get info :html-container)
	"div")))

;;;; Horizontal Rule

(defun org-html-horizontal-rule (_horizontal-rule _contents info)
  "Transcode an HORIZONTAL-RULE  object from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (org-html-close-tag "hr" nil info))

;;;; Inline Src Block

(defun org-html-inline-src-block (inline-src-block _contents info)
  "Transcode an INLINE-SRC-BLOCK element from Org to HTML.
CONTENTS holds the contents of the item.  INFO is a plist holding
contextual information."
  (let* ((lang (org-element-property :language inline-src-block))
	 (code (org-html-fontify-code
		(org-element-property :value inline-src-block)
		lang))
	 (label
	  (let ((lbl (and (org-element-property :name inline-src-block)
			  (org-export-get-reference inline-src-block info))))
	    (if (not lbl) "" (format " id=\"%s\"" lbl)))))
    (format "<code class=\"src src-%s\"%s>%s</code>" lang label code)))

;;;; Inlinetask

(defun org-html-inlinetask (inlinetask contents info)
  "Transcode an INLINETASK element from Org to HTML.
CONTENTS holds the contents of the block.  INFO is a plist
holding contextual information."
  (let* ((todo (and (plist-get info :with-todo-keywords)
		    (let ((todo (org-element-property :todo-keyword inlinetask)))
		      (and todo (org-export-data todo info)))))
	 (todo-type (and todo (org-element-property :todo-type inlinetask)))
	 (priority (and (plist-get info :with-priority)
			(org-element-property :priority inlinetask)))
	 (text (org-export-data (org-element-property :title inlinetask) info))
	 (tags (and (plist-get info :with-tags)
		    (org-export-get-tags inlinetask info))))
    (funcall (plist-get info :html-format-inlinetask-function)
	     todo todo-type priority text tags contents info)))

(defun org-html-format-inlinetask-default-function
  (todo todo-type priority text tags contents info)
  "Default format function for inlinetasks.
See `org-html-format-inlinetask-function' for details."
  (format "<div class=\"inlinetask\">\n<b>%s</b>%s\n%s</div>"
	  (org-html-format-headline-default-function
	   todo todo-type priority text tags info)
	  (org-html-close-tag "br" nil info)
	  contents))

;;;; Italic

(defun org-html-italic (_italic contents info)
  "Transcode ITALIC from Org to HTML.
CONTENTS is the text with italic markup.  INFO is a plist holding
contextual information."
  (format
   (or (cdr (assq 'italic (plist-get info :html-text-markup-alist))) "%s")
   contents))

;;;; Item

(defun org-html-checkbox (checkbox info)
  "Format CHECKBOX into HTML.
INFO is a plist holding contextual information.  See
`org-html-checkbox-type' for customization options."
  (cdr (assq checkbox
	     (cdr (assq (plist-get info :html-checkbox-type)
			org-html-checkbox-types)))))

(defun org-html-format-list-item (contents type checkbox info
					   &optional term-counter-id
					   headline)
  "Format a list item into HTML."
  (let ((class (if checkbox
		   (format " class=\"%s\""
			   (symbol-name checkbox)) ""))
	(checkbox (concat (org-html-checkbox checkbox info)
			  (and checkbox " ")))
	(br (org-html-close-tag "br" nil info))
	(extra-newline (if (and (org-string-nw-p contents) headline) "\n" "")))
    (concat
     (pcase type
       (`ordered
	(let* ((counter term-counter-id)
	       (extra (if counter (format " value=\"%s\"" counter) "")))
	  (concat
	   (format "<li%s%s>" class extra)
	   (when headline (concat headline br)))))
       (`unordered
	(let* ((id term-counter-id)
	       (extra (if id (format " id=\"%s\"" id) "")))
	  (concat
	   (format "<li%s%s>" class extra)
	   (when headline (concat headline br)))))
       (`descriptive
	(let* ((term term-counter-id))
	  (setq term (or term "(no term)"))
	  ;; Check-boxes in descriptive lists are associated to tag.
	  (concat (format "<dt%s>%s</dt>"
			  class (concat checkbox term))
		  "<dd>"))))
     (unless (eq type 'descriptive) checkbox)
     extra-newline
     (and (org-string-nw-p contents) (org-trim contents))
     extra-newline
     (pcase type
       (`ordered "</li>")
       (`unordered "</li>")
       (`descriptive "</dd>")))))

(defun org-html-item (item contents info)
  "Transcode an ITEM element from Org to HTML.
CONTENTS holds the contents of the item.  INFO is a plist holding
contextual information."
  (let* ((plain-list (org-export-get-parent item))
	 (type (org-element-property :type plain-list))
	 (counter (org-element-property :counter item))
	 (checkbox (org-element-property :checkbox item))
	 (tag (let ((tag (org-element-property :tag item)))
		(and tag (org-export-data tag info)))))
    (org-html-format-list-item
     contents type checkbox info (or tag counter))))

;;;; Keyword

(defun org-html-keyword (keyword _contents info)
  "Transcode a KEYWORD element from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (let ((key (org-element-property :key keyword))
	(value (org-element-property :value keyword)))
    (cond
     ((string= key "HTML") value)
     ((string= key "TOC")
      (let ((case-fold-search t))
	(cond
	 ((string-match "\\<headlines\\>" value)
	  (let ((depth (and (string-match "\\<[0-9]+\\>" value)
			    (string-to-number (match-string 0 value))))
		(scope
		 (cond
		  ((string-match ":target +\\(\".+?\"\\|\\S-+\\)" value) ;link
		   (org-export-resolve-link
		    (org-strip-quotes (match-string 1 value)) info))
		  ((string-match-p "\\<local\\>" value) keyword)))) ;local
	    (org-html-toc depth info scope)))
	 ((string= "listings" value) (org-html-list-of-listings info))
	 ((string= "tables" value) (org-html-list-of-tables info))))))))

;;;; Latex Environment

(defun org-html-format-latex (latex-frag processing-type info)
  "Format a LaTeX fragment LATEX-FRAG into HTML.
PROCESSING-TYPE designates the tool used for conversion.  It can
be `mathjax', `verbatim', nil, t or symbols in
`org-preview-latex-process-alist', e.g., `dvipng', `dvisvgm' or
`imagemagick'.  See `org-html-with-latex' for more information.
INFO is a plist containing export properties."
  (let ((cache-relpath "") (cache-dir ""))
    (unless (eq processing-type 'mathjax)
      (let ((bfn (or (buffer-file-name)
		     (make-temp-name
		      (expand-file-name "latex" temporary-file-directory))))
	    (latex-header
	     (let ((header (plist-get info :latex-header)))
	       (and header
		    (concat (mapconcat
			     (lambda (line) (concat "#+LATEX_HEADER: " line))
			     (org-split-string header "\n")
			     "\n")
			    "\n")))))
	(setq cache-relpath
	      (concat (file-name-as-directory org-preview-latex-image-directory)
		      (file-name-sans-extension
		       (file-name-nondirectory bfn)))
	      cache-dir (file-name-directory bfn))
	;; Re-create LaTeX environment from original buffer in
	;; temporary buffer so that dvipng/imagemagick can properly
	;; turn the fragment into an image.
	(setq latex-frag (concat latex-header latex-frag))))
    (with-temp-buffer
      (insert latex-frag)
      (org-format-latex cache-relpath nil nil cache-dir nil
			"Creating LaTeX Image..." nil processing-type)
      (buffer-string))))

(defun org-html--wrap-latex-environment (contents _ &optional caption label)
  "Wrap CONTENTS string within appropriate environment for equations.
When optional arguments CAPTION and LABEL are given, use them for
caption and \"id\" attribute."
  (format "\n<div%s class=\"equation-container\">\n%s%s\n</div>"
          ;; ID.
          (if (org-string-nw-p label) (format " id=\"%s\"" label) "")
          ;; Contents.
          (format "<span class=\"equation\">\n%s\n</span>" contents)
          ;; Caption.
          (if (not (org-string-nw-p caption)) ""
            (format "\n<span class=\"equation-label\">\n%s\n</span>"
                    caption))))

(defun org-html--math-environment-p (element &optional _)
  "Non-nil when ELEMENT is a LaTeX math environment.
Math environments match the regular expression defined in
`org-latex-math-environments-re'.  This function is meant to be
used as a predicate for `org-export-get-ordinal' or a value to
`org-html-standalone-image-predicate'."
  (string-match-p org-latex-math-environments-re
                  (org-element-property :value element)))

(defun org-html--unlabel-latex-environment (latex-frag)
  "Change environment in LATEX-FRAG string to an unnumbered one.
For instance, change an 'equation' environment to 'equation*'."
  (replace-regexp-in-string
   "\\`[ \t]*\\\\begin{\\([^*]+?\\)}"
   "\\1*"
   (replace-regexp-in-string "^[ \t]*\\\\end{\\([^*]+?\\)}[ \r\t\n]*\\'"
			     "\\1*"
			     latex-frag nil nil 1)
   nil nil 1))

(defun org-html-latex-environment (latex-environment _contents info)
  "Transcode a LATEX-ENVIRONMENT element from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (let ((processing-type (plist-get info :with-latex))
	(latex-frag (org-remove-indentation
		     (org-element-property :value latex-environment)))
        (attributes (org-export-read-attribute :attr_html latex-environment))
        (label (and (org-element-property :name latex-environment)
                    (org-export-get-reference latex-environment info)))
        (caption (number-to-string
                  (org-export-get-ordinal
                   latex-environment info nil
                   #'org-html--math-environment-p))))
    (cond
     ((memq processing-type '(t mathjax))
      (org-html-format-latex
       (if (org-string-nw-p label)
	   (replace-regexp-in-string "\\`.*"
				     (format "\\&\n\\\\label{%s}" label)
				     latex-frag)
	 latex-frag)
       'mathjax info))
     ((assq processing-type org-preview-latex-process-alist)
      (let ((formula-link
             (org-html-format-latex
              (org-html--unlabel-latex-environment latex-frag)
              processing-type info)))
        (when (and formula-link (string-match "file:\\([^]]*\\)" formula-link))
          (org-html--wrap-latex-environment
           (org-html--format-image
            (match-string 1 formula-link) attributes info)
           info caption label))))
     (t (org-html--wrap-latex-environment latex-frag info caption label)))))

;;;; Latex Fragment

(defun org-html-latex-fragment (latex-fragment _contents info)
  "Transcode a LATEX-FRAGMENT object from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (let ((latex-frag (org-element-property :value latex-fragment))
	(processing-type (plist-get info :with-latex)))
    (cond
     ((memq processing-type '(t mathjax))
      (org-html-format-latex latex-frag 'mathjax info))
     ((assq processing-type org-preview-latex-process-alist)
      (let ((formula-link
	     (org-html-format-latex latex-frag processing-type info)))
	(when (and formula-link (string-match "file:\\([^]]*\\)" formula-link))
	  (org-html--format-image (match-string 1 formula-link) nil info))))
     (t latex-frag))))

;;;; Line Break

(defun org-html-line-break (_line-break _contents info)
  "Transcode a LINE-BREAK object from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (concat (org-html-close-tag "br" nil info) "\n"))

;;;; Link

(defun org-html-image-link-filter (data _backend info)
  (org-export-insert-image-links data info org-html-inline-image-rules))

(defun org-html-inline-image-p (link info)
  "Non-nil when LINK is meant to appear as an image.
INFO is a plist used as a communication channel.  LINK is an
inline image when it has no description and targets an image
file (see `org-html-inline-image-rules' for more information), or
if its description is a single link targeting an image file."
  (if (not (org-element-contents link))
      (org-export-inline-image-p
       link (plist-get info :html-inline-image-rules))
    (not
     (let ((link-count 0))
       (org-element-map (org-element-contents link)
	   (cons 'plain-text org-element-all-objects)
	 (lambda (obj)
	   (pcase (org-element-type obj)
	     (`plain-text (org-string-nw-p obj))
	     (`link (if (= link-count 1) t
		      (cl-incf link-count)
		      (not (org-export-inline-image-p
			    obj (plist-get info :html-inline-image-rules)))))
	     (_ t)))
         info t)))))

(defvar org-html-standalone-image-predicate)
(defun org-html-standalone-image-p (element info)
  "Non-nil if ELEMENT is a standalone image.

INFO is a plist holding contextual information.

An element or object is a standalone image when

  - its type is `paragraph' and its sole content, save for white
    spaces, is a link that qualifies as an inline image;

  - its type is `link' and its containing paragraph has no other
    content save white spaces.

Bind `org-html-standalone-image-predicate' to constrain paragraph
further.  For example, to check for only captioned standalone
images, set it to:

  (lambda (paragraph) (org-element-property :caption paragraph))"
  (let ((paragraph (pcase (org-element-type element)
		     (`paragraph element)
		     (`link (org-export-get-parent element)))))
    (and (eq (org-element-type paragraph) 'paragraph)
	 (or (not (fboundp 'org-html-standalone-image-predicate))
	     (funcall org-html-standalone-image-predicate paragraph))
	 (catch 'exit
	   (let ((link-count 0))
	     (org-element-map (org-element-contents paragraph)
		 (cons 'plain-text org-element-all-objects)
	       (lambda (obj)
		 (when (pcase (org-element-type obj)
			 (`plain-text (org-string-nw-p obj))
			 (`link (or (> (cl-incf link-count) 1)
				    (not (org-html-inline-image-p obj info))))
			 (_ t))
		   (throw 'exit nil)))
	       info nil 'link)
	     (= link-count 1))))))

(defun org-html-link (link desc info)
  "Transcode a LINK object from Org to HTML.
DESC is the description part of the link, or the empty string.
INFO is a plist holding contextual information.  See
`org-export-data'."
  (let* ((link-org-files-as-html-maybe
	  (lambda (raw-path info)
	    ;; Treat links to `file.org' as links to `file.html', if
	    ;; needed.  See `org-html-link-org-files-as-html'.
	    (cond
	     ((and (plist-get info :html-link-org-files-as-html)
		   (string= ".org"
			    (downcase (file-name-extension raw-path "."))))
	      (concat (file-name-sans-extension raw-path) "."
		      (plist-get info :html-extension)))
	     (t raw-path))))
	 (type (org-element-property :type link))
	 (raw-path (org-element-property :path link))
	 ;; Ensure DESC really exists, or set it to nil.
	 (desc (org-string-nw-p desc))
	 (path
	  (cond
	   ((member type '("http" "https" "ftp" "mailto" "news"))
	    (url-encode-url (concat type ":" raw-path)))
	   ((string= type "file")
	    ;; During publishing, turn absolute file names belonging
	    ;; to base directory into relative file names.  Otherwise,
	    ;; append "file" protocol to absolute file name.
	    (setq raw-path
		  (org-export-file-uri
		   (org-publish-file-relative-name raw-path info)))
	    ;; Possibly append `:html-link-home' to relative file
	    ;; name.
	    (let ((home (and (plist-get info :html-link-home)
			     (org-trim (plist-get info :html-link-home)))))
	      (when (and home
			 (plist-get info :html-link-use-abs-url)
			 (file-name-absolute-p raw-path))
		(setq raw-path (concat (file-name-as-directory home) raw-path))))
	    ;; Maybe turn ".org" into ".html".
	    (setq raw-path (funcall link-org-files-as-html-maybe raw-path info))
	    ;; Add search option, if any.  A search option can be
	    ;; relative to a custom-id, a headline title, a name or
	    ;; a target.
	    (let ((option (org-element-property :search-option link)))
	      (if (not option) raw-path
		(let ((path (org-element-property :path link)))
		  (concat raw-path
			  "#"
			  (org-publish-resolve-external-link option path t))))))
	   (t raw-path)))
	 (attributes-plist
	  (org-combine-plists
	   ;; Extract attributes from parent's paragraph.  HACK: Only
	   ;; do this for the first link in parent (inner image link
	   ;; for inline images).  This is needed as long as
	   ;; attributes cannot be set on a per link basis.
	   (let* ((parent (org-export-get-parent-element link))
		  (link (let ((container (org-export-get-parent link)))
			  (if (and (eq 'link (org-element-type container))
				   (org-html-inline-image-p link info))
			      container
			    link))))
	     (and (eq link (org-element-map parent 'link #'identity info t))
		  (org-export-read-attribute :attr_html parent)))
	   ;; Also add attributes from link itself.  Currently, those
	   ;; need to be added programmatically before `org-html-link'
	   ;; is invoked, for example, by backends building upon HTML
	   ;; export.
	   (org-export-read-attribute :attr_html link)))
	 (attributes
	  (let ((attr (org-html--make-attribute-string attributes-plist)))
	    (if (org-string-nw-p attr) (concat " " attr) ""))))
    (cond
     ;; Link type is handled by a special function.
     ((org-export-custom-protocol-maybe link desc 'html))
     ;; Image file.
     ((and (plist-get info :html-inline-images)
	   (org-export-inline-image-p
	    link (plist-get info :html-inline-image-rules)))
      (org-html--format-image path attributes-plist info))
     ;; Radio target: Transcode target's contents and use them as
     ;; link's description.
     ((string= type "radio")
      (let ((destination (org-export-resolve-radio-link link info)))
	(if (not destination) desc
	  (format "<a href=\"#%s\"%s>%s</a>"
		  (org-export-get-reference destination info)
		  attributes
		  desc))))
     ;; Links pointing to a headline: Find destination and build
     ;; appropriate referencing command.
     ((member type '("custom-id" "fuzzy" "id"))
      (let ((destination (if (string= type "fuzzy")
			     (org-export-resolve-fuzzy-link link info)
			   (org-export-resolve-id-link link info))))
	(pcase (org-element-type destination)
	  ;; ID link points to an external file.
	  (`plain-text
	   (let ((fragment (concat "ID-" path))
		 ;; Treat links to ".org" files as ".html", if needed.
		 (path (funcall link-org-files-as-html-maybe
				destination info)))
	     (format "<a href=\"%s#%s\"%s>%s</a>"
		     path fragment attributes (or desc destination))))
	  ;; Fuzzy link points nowhere.
	  (`nil
	   (format "<i>%s</i>"
		   (or desc
		       (org-export-data
			(org-element-property :raw-link link) info))))
	  ;; Link points to a headline.
	  (`headline
	   (let ((href (or (org-element-property :CUSTOM_ID destination)
			   (org-export-get-reference destination info)))
		 ;; What description to use?
		 (desc
		  ;; Case 1: Headline is numbered and LINK has no
		  ;; description.  Display section number.
		  (if (and (org-export-numbered-headline-p destination info)
			   (not desc))
		      (mapconcat #'number-to-string
				 (org-export-get-headline-number
				  destination info) ".")
		    ;; Case 2: Either the headline is un-numbered or
		    ;; LINK has a custom description.  Display LINK's
		    ;; description or headline's title.
		    (or desc
			(org-export-data
			 (org-element-property :title destination) info)))))
	     (format "<a href=\"#%s\"%s>%s</a>" href attributes desc)))
	  ;; Fuzzy link points to a target or an element.
	  (_
           (if (and destination
                    (memq (plist-get info :with-latex) '(mathjax t))
                    (eq 'latex-environment (org-element-type destination))
                    (eq 'math (org-latex--environment-type destination)))
               ;; Caption and labels are introduced within LaTeX
	       ;; environment.  Use "eqref" macro to refer to those in
	       ;; the document.
               (format "\\eqref{%s}"
                       (org-export-get-reference destination info))
             (let* ((ref (org-export-get-reference destination info))
                    (org-html-standalone-image-predicate
                     #'org-html--has-caption-p)
                    (counter-predicate
                     (if (eq 'latex-environment (org-element-type destination))
                         #'org-html--math-environment-p
                       #'org-html--has-caption-p))
                    (number
		     (cond
		      (desc nil)
		      ((org-html-standalone-image-p destination info)
		       (org-export-get-ordinal
			(org-element-map destination 'link #'identity info t)
			info 'link 'org-html-standalone-image-p))
		      (t (org-export-get-ordinal
			  destination info nil counter-predicate))))
                    (desc
		     (cond (desc)
			   ((not number) "No description for this link")
			   ((numberp number) (number-to-string number))
			   (t (mapconcat #'number-to-string number ".")))))
               (format "<a href=\"#%s\"%s>%s</a>" ref attributes desc)))))))
     ;; Coderef: replace link with the reference name or the
     ;; equivalent line number.
     ((string= type "coderef")
      (let ((fragment (concat "coderef-" (org-html-encode-plain-text path))))
	(format "<a href=\"#%s\" %s%s>%s</a>"
		fragment
		(format "class=\"coderef\" onmouseover=\"CodeHighlightOn(this, \
'%s');\" onmouseout=\"CodeHighlightOff(this, '%s');\""
			fragment fragment)
		attributes
		(format (org-export-get-coderef-format path desc)
			(org-export-resolve-coderef path info)))))
     ;; External link with a description part.
     ((and path desc)
      (format "<a href=\"%s\"%s>%s</a>"
	      (org-html-encode-plain-text path)
	      attributes
	      desc))
     ;; External link without a description part.
     (path
      (let ((path (org-html-encode-plain-text path)))
	(format "<a href=\"%s\"%s>%s</a>" path attributes path)))
     ;; No path, only description.  Try to do something useful.
     (t
      (format "<i>%s</i>" desc)))))

;;;; Node Property

(defun org-html-node-property (node-property _contents _info)
  "Transcode a NODE-PROPERTY element from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual
information."
  (format "%s:%s"
          (org-element-property :key node-property)
          (let ((value (org-element-property :value node-property)))
            (if value (concat " " value) ""))))

;;;; Paragraph

(defun org-html-paragraph (paragraph contents info)
  "Transcode a PARAGRAPH element from Org to HTML.
CONTENTS is the contents of the paragraph, as a string.  INFO is
the plist used as a communication channel."
  (let* ((parent (org-export-get-parent paragraph))
	 (parent-type (org-element-type parent))
	 (style '((footnote-definition " class=\"footpara\"")
		  (org-data " class=\"footpara\"")))
	 (attributes (org-html--make-attribute-string
		      (org-export-read-attribute :attr_html paragraph)))
	 (extra (or (cadr (assq parent-type style)) "")))
    (cond
     ((and (eq parent-type 'item)
	   (not (org-export-get-previous-element paragraph info))
	   (let ((followers (org-export-get-next-element paragraph info 2)))
	     (and (not (cdr followers))
		  (memq (org-element-type (car followers)) '(nil plain-list)))))
      ;; First paragraph in an item has no tag if it is alone or
      ;; followed, at most, by a sub-list.
      contents)
     ((org-html-standalone-image-p paragraph info)
      ;; Standalone image.
      (let ((caption
	     (let ((raw (org-export-data
			 (org-export-get-caption paragraph) info))
		   (org-html-standalone-image-predicate
		    #'org-html--has-caption-p))
	       (if (not (org-string-nw-p raw)) raw
		 (concat "<span class=\"figure-number\">"
			 (format (org-html--translate "Figure %d:" info)
				 (org-export-get-ordinal
				  (org-element-map paragraph 'link
				    #'identity info t)
				  info nil #'org-html-standalone-image-p))
			 " </span>"
			 raw))))
	    (label (and (org-element-property :name paragraph)
			(org-export-get-reference paragraph info))))
	(org-html--wrap-image contents info caption label)))
     ;; Regular paragraph.
     (t (format "<p%s%s>\n%s</p>"
		(if (org-string-nw-p attributes)
		    (concat " " attributes) "")
		extra contents)))))

;;;; Plain List

(defun org-html-plain-list (plain-list contents _info)
  "Transcode a PLAIN-LIST element from Org to HTML.
CONTENTS is the contents of the list.  INFO is a plist holding
contextual information."
  (let* ((type (pcase (org-element-property :type plain-list)
		 (`ordered "ol")
		 (`unordered "ul")
		 (`descriptive "dl")
		 (other (error "Unknown HTML list type: %s" other))))
	 (class (format "org-%s" type))
	 (attributes (org-export-read-attribute :attr_html plain-list)))
    (format "<%s %s>\n%s</%s>"
	    type
	    (org-html--make-attribute-string
	     (plist-put attributes :class
			(org-trim
			 (mapconcat #'identity
				    (list class (plist-get attributes :class))
				    " "))))
	    contents
	    type)))

;;;; Plain Text

(defun org-html-convert-special-strings (string)
  "Convert special characters in STRING to HTML."
  (dolist (a org-html-special-string-regexps string)
    (let ((re (car a))
	  (rpl (cdr a)))
      (setq string (replace-regexp-in-string re rpl string t)))))

(defun org-html-encode-plain-text (text)
  "Convert plain text characters from TEXT to HTML equivalent.
Possible conversions are set in `org-html-protect-char-alist'."
  (dolist (pair org-html-protect-char-alist text)
    (setq text (replace-regexp-in-string (car pair) (cdr pair) text t t))))

(defun org-html-plain-text (text info)
  "Transcode a TEXT string from Org to HTML.
TEXT is the string to transcode.  INFO is a plist holding
contextual information."
  (let ((output text))
    ;; Protect following characters: <, >, &.
    (setq output (org-html-encode-plain-text output))
    ;; Handle smart quotes.  Be sure to provide original string since
    ;; OUTPUT may have been modified.
    (when (plist-get info :with-smart-quotes)
      (setq output (org-export-activate-smart-quotes output :html info text)))
    ;; Handle special strings.
    (when (plist-get info :with-special-strings)
      (setq output (org-html-convert-special-strings output)))
    ;; Handle break preservation if required.
    (when (plist-get info :preserve-breaks)
      (setq output
	    (replace-regexp-in-string
	     "\\(\\\\\\\\\\)?[ \t]*\n"
	     (concat (org-html-close-tag "br" nil info) "\n") output)))
    ;; Return value.
    output))


;; Planning

(defun org-html-planning (planning _contents info)
  "Transcode a PLANNING element from Org to HTML.
CONTENTS is nil.  INFO is a plist used as a communication
channel."
  (format
   "<p><span class=\"timestamp-wrapper\">%s</span></p>"
   (org-trim
    (mapconcat
     (lambda (pair)
       (let ((timestamp (cdr pair)))
	 (when timestamp
	   (let ((string (car pair)))
	     (format "<span class=\"timestamp-kwd\">%s</span> \
<span class=\"timestamp\">%s</span> "
		     string
		     (org-html-plain-text (org-timestamp-translate timestamp)
					  info))))))
     `((,org-closed-string . ,(org-element-property :closed planning))
       (,org-deadline-string . ,(org-element-property :deadline planning))
       (,org-scheduled-string . ,(org-element-property :scheduled planning)))
     ""))))

;;;; Property Drawer

(defun org-html-property-drawer (_property-drawer contents _info)
  "Transcode a PROPERTY-DRAWER element from Org to HTML.
CONTENTS holds the contents of the drawer.  INFO is a plist
holding contextual information."
  (and (org-string-nw-p contents)
       (format "<pre class=\"example\">\n%s</pre>" contents)))

;;;; Quote Block

(defun org-html-quote-block (quote-block contents _info)
  "Transcode a QUOTE-BLOCK element from Org to HTML.
CONTENTS holds the contents of the block.  INFO is a plist
holding contextual information."
  (format "<blockquote%s>\n%s</blockquote>"
	  (let* ((name (org-element-property :name quote-block))
		 (attributes (org-export-read-attribute :attr_html quote-block))
		 (a (org-html--make-attribute-string
		     (if (or (not name) (plist-member attributes :id))
			 attributes
		       (plist-put attributes :id name)))))
	    (if (org-string-nw-p a) (concat " " a) ""))
	  contents))

;;;; Section

(defun org-html-section (section contents info)
  "Transcode a SECTION element from Org to HTML.
CONTENTS holds the contents of the section.  INFO is a plist
holding contextual information."
  (let ((parent (org-export-get-parent-headline section)))
    ;; Before first headline: no container, just return CONTENTS.
    (if (not parent) contents
      ;; Get div's class and id references.
      (let* ((class-num (+ (org-export-get-relative-level parent info)
			   (1- (plist-get info :html-toplevel-hlevel))))
	     (section-number
	      (and (org-export-numbered-headline-p parent info)
		   (mapconcat
		    #'number-to-string
		    (org-export-get-headline-number parent info) "-"))))
        ;; Build return value.
	(format "<div class=\"outline-text-%d\" id=\"text-%s\">\n%s</div>\n"
		class-num
		(or (org-element-property :CUSTOM_ID parent)
		    section-number
		    (org-export-get-reference parent info))
		(or contents ""))))))

;;;; Radio Target

(defun org-html-radio-target (radio-target text info)
  "Transcode a RADIO-TARGET object from Org to HTML.
TEXT is the text of the target.  INFO is a plist holding
contextual information."
  (let ((ref (org-export-get-reference radio-target info)))
    (org-html--anchor ref text nil info)))

;;;; Special Block

(defun org-html-special-block (special-block contents info)
  "Transcode a SPECIAL-BLOCK element from Org to HTML.
CONTENTS holds the contents of the block.  INFO is a plist
holding contextual information."
  (let* ((block-type (org-element-property :type special-block))
         (html5-fancy (and (org-html--html5-fancy-p info)
                           (member block-type org-html-html5-elements)))
         (attributes (org-export-read-attribute :attr_html special-block)))
    (unless html5-fancy
      (let ((class (plist-get attributes :class)))
        (setq attributes (plist-put attributes :class
                                    (if class (concat class " " block-type)
                                      block-type)))))
    (let* ((contents (or contents ""))
	   (name (org-element-property :name special-block))
	   (a (org-html--make-attribute-string
	       (if (or (not name) (plist-member attributes :id))
		   attributes
		 (plist-put attributes :id name))))
	   (str (if (org-string-nw-p a) (concat " " a) "")))
      (if html5-fancy
	  (format "<%s%s>\n%s</%s>" block-type str contents block-type)
	(format "<div%s>\n%s\n</div>" str contents)))))

;;;; Src Block

(defun org-html-src-block (src-block _contents info)
  "Transcode a SRC-BLOCK element from Org to HTML.
CONTENTS holds the contents of the item.  INFO is a plist holding
contextual information."
  (if (org-export-read-attribute :attr_html src-block :textarea)
      (org-html--textarea-block src-block)
    (let* ((lang (org-element-property :language src-block))
	  (code (org-html-format-code src-block info))
	  (label (let ((lbl (and (org-element-property :name src-block)
				 (org-export-get-reference src-block info))))
		   (if lbl (format " id=\"%s\"" lbl) "")))
	  (klipsify  (and  (plist-get info :html-klipsify-src)
                           (member lang '("javascript" "js"
					  "ruby" "scheme" "clojure" "php" "html")))))
      (if (not lang) (format "<pre class=\"example\"%s>\n%s</pre>" label code)
	(format "<div class=\"org-src-container\">\n%s%s\n</div>"
		;; Build caption.
		(let ((caption (org-export-get-caption src-block)))
		  (if (not caption) ""
		    (let ((listing-number
			   (format
			    "<span class=\"listing-number\">%s </span>"
			    (format
			     (org-html--translate "Listing %d:" info)
			     (org-export-get-ordinal
			      src-block info nil #'org-html--has-caption-p)))))
		      (format "<label class=\"org-src-name\">%s%s</label>"
			      listing-number
			      (org-trim (org-export-data caption info))))))
		;; Contents.
		(if klipsify
		    (format "<pre><code class=\"src src-%s\"%s%s>%s</code></pre>"
			    lang
			    label
			    (if (string= lang "html")
				" data-editor-type=\"html\""
			      "")
			    code)
		  (format "<pre class=\"src src-%s\"%s>%s</pre>"
                          lang label code)))))))

;;;; Statistics Cookie

(defun org-html-statistics-cookie (statistics-cookie _contents _info)
  "Transcode a STATISTICS-COOKIE object from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (let ((cookie-value (org-element-property :value statistics-cookie)))
    (format "<code>%s</code>" cookie-value)))

;;;; Strike-Through

(defun org-html-strike-through (_strike-through contents info)
  "Transcode STRIKE-THROUGH from Org to HTML.
CONTENTS is the text with strike-through markup.  INFO is a plist
holding contextual information."
  (format
   (or (cdr (assq 'strike-through (plist-get info :html-text-markup-alist)))
       "%s")
   contents))

;;;; Subscript

(defun org-html-subscript (_subscript contents _info)
  "Transcode a SUBSCRIPT object from Org to HTML.
CONTENTS is the contents of the object.  INFO is a plist holding
contextual information."
  (format "<sub>%s</sub>" contents))

;;;; Superscript

(defun org-html-superscript (_superscript contents _info)
  "Transcode a SUPERSCRIPT object from Org to HTML.
CONTENTS is the contents of the object.  INFO is a plist holding
contextual information."
  (format "<sup>%s</sup>" contents))

;;;; Table Cell

(defun org-html-table-cell (table-cell contents info)
  "Transcode a TABLE-CELL element from Org to HTML.
CONTENTS is nil.  INFO is a plist used as a communication
channel."
  (let* ((table-row (org-export-get-parent table-cell))
	 (table (org-export-get-parent-table table-cell))
	 (cell-attrs
	  (if (not (plist-get info :html-table-align-individual-fields)) ""
	    (format (if (and (boundp 'org-html-format-table-no-css)
			     org-html-format-table-no-css)
			" align=\"%s\"" " class=\"org-%s\"")
		    (org-export-table-cell-alignment table-cell info)))))
    (when (or (not contents) (string= "" (org-trim contents)))
      (setq contents "&#xa0;"))
    (cond
     ((and (org-export-table-has-header-p table info)
	   (= 1 (org-export-table-row-group table-row info)))
      (let ((header-tags (plist-get info :html-table-header-tags)))
	(concat "\n" (format (car header-tags) "col" cell-attrs)
		contents
		(cdr header-tags))))
     ((and (plist-get info :html-table-use-header-tags-for-first-column)
	   (zerop (cdr (org-export-table-cell-address table-cell info))))
      (let ((header-tags (plist-get info :html-table-header-tags)))
	(concat "\n" (format (car header-tags) "row" cell-attrs)
		contents
		(cdr header-tags))))
     (t (let ((data-tags (plist-get info :html-table-data-tags)))
	  (concat "\n" (format (car data-tags) cell-attrs)
		  contents
		  (cdr data-tags)))))))

;;;; Table Row

(defun org-html-table-row (table-row contents info)
  "Transcode a TABLE-ROW element from Org to HTML.
CONTENTS is the contents of the row.  INFO is a plist used as a
communication channel."
  ;; Rules are ignored since table separators are deduced from
  ;; borders of the current row.
  (when (eq (org-element-property :type table-row) 'standard)
    (let* ((group (org-export-table-row-group table-row info))
	   (number (org-export-table-row-number table-row info))
	   (start-group-p
	    (org-export-table-row-starts-rowgroup-p table-row info))
	   (end-group-p
	    (org-export-table-row-ends-rowgroup-p table-row info))
	   (topp (and (equal start-group-p '(top))
		      (equal end-group-p '(below top))))
	   (bottomp (and (equal start-group-p '(above))
			 (equal end-group-p '(bottom above))))
           (row-open-tag
            (pcase (plist-get info :html-table-row-open-tag)
              ((and accessor (pred functionp))
               (funcall accessor
			number group start-group-p end-group-p topp bottomp))
	      (accessor accessor)))
           (row-close-tag
            (pcase (plist-get info :html-table-row-close-tag)
              ((and accessor (pred functionp))
               (funcall accessor
			number group start-group-p end-group-p topp bottomp))
	      (accessor accessor)))
	   (group-tags
	    (cond
	     ;; Row belongs to second or subsequent groups.
	     ((not (= 1 group)) '("<tbody>" . "\n</tbody>"))
	     ;; Row is from first group.  Table has >=1 groups.
	     ((org-export-table-has-header-p
	       (org-export-get-parent-table table-row) info)
	      '("<thead>" . "\n</thead>"))
	     ;; Row is from first and only group.
	     (t '("<tbody>" . "\n</tbody>")))))
      (concat (and start-group-p (car group-tags))
	      (concat "\n"
		      row-open-tag
		      contents
		      "\n"
		      row-close-tag)
	      (and end-group-p (cdr group-tags))))))

;;;; Table

(defun org-html-table-first-row-data-cells (table info)
  "Transcode the first row of TABLE.
INFO is a plist used as a communication channel."
  (let ((table-row
	 (org-element-map table 'table-row
	   (lambda (row)
	     (unless (eq (org-element-property :type row) 'rule) row))
	   info 'first-match))
	(special-column-p (org-export-table-has-special-column-p table)))
    (if (not special-column-p) (org-element-contents table-row)
      (cdr (org-element-contents table-row)))))

(defun org-html-table--table.el-table (table _info)
  "Format table.el tables into HTML.
INFO is a plist used as a communication channel."
  (when (eq (org-element-property :type table) 'table.el)
    (require 'table)
    (let ((outbuf (with-current-buffer
		      (get-buffer-create "*org-export-table*")
		    (erase-buffer) (current-buffer))))
      (with-temp-buffer
	(insert (org-element-property :value table))
	(goto-char 1)
	(re-search-forward "^[ \t]*|[^|]" nil t)
	(table-generate-source 'html outbuf))
      (with-current-buffer outbuf
	(prog1 (org-trim (buffer-string))
	  (kill-buffer) )))))

(defun org-html-table (table contents info)
  "Transcode a TABLE element from Org to HTML.
CONTENTS is the contents of the table.  INFO is a plist holding
contextual information."
  (if (eq (org-element-property :type table) 'table.el)
      ;; "table.el" table.  Convert it using appropriate tools.
      (org-html-table--table.el-table table info)
    ;; Standard table.
    (let* ((caption (org-export-get-caption table))
	   (number (org-export-get-ordinal
		    table info nil #'org-html--has-caption-p))
	   (attributes
	    (org-html--make-attribute-string
	     (org-combine-plists
	      (and (org-element-property :name table)
		   (list :id (org-export-get-reference table info)))
	      (and (not (org-html-html5-p info))
		   (plist-get info :html-table-attributes))
	      (org-export-read-attribute :attr_html table))))
	   (alignspec
	    (if (bound-and-true-p org-html-format-table-no-css)
		"align=\"%s\""
	      "class=\"org-%s\""))
	   (table-column-specs
	    (lambda (table info)
	      (mapconcat
	       (lambda (table-cell)
		 (let ((alignment (org-export-table-cell-alignment
				   table-cell info)))
		   (concat
		    ;; Begin a colgroup?
		    (when (org-export-table-cell-starts-colgroup-p
			   table-cell info)
		      "\n<colgroup>")
		    ;; Add a column.  Also specify its alignment.
		    (format "\n%s"
			    (org-html-close-tag
			     "col" (concat " " (format alignspec alignment)) info))
		    ;; End a colgroup?
		    (when (org-export-table-cell-ends-colgroup-p
			   table-cell info)
		      "\n</colgroup>"))))
	       (org-html-table-first-row-data-cells table info) "\n"))))
      (format "<table%s>\n%s\n%s\n%s</table>"
	      (if (equal attributes "") "" (concat " " attributes))
	      (if (not caption) ""
		(format (if (plist-get info :html-table-caption-above)
			    "<caption class=\"t-above\">%s</caption>"
			  "<caption class=\"t-bottom\">%s</caption>")
			(concat
			 "<span class=\"table-number\">"
			 (format (org-html--translate "Table %d:" info) number)
			 "</span> " (org-export-data caption info))))
	      (funcall table-column-specs table info)
	      contents))))

;;;; Target

(defun org-html-target (target _contents info)
  "Transcode a TARGET object from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual
information."
  (let ((ref (org-export-get-reference target info)))
    (org-html--anchor ref nil nil info)))

;;;; Timestamp

(defun org-html-timestamp (timestamp _contents info)
  "Transcode a TIMESTAMP object from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual
information."
  (let ((value (org-html-plain-text (org-timestamp-translate timestamp) info)))
    (format "<span class=\"timestamp-wrapper\"><span class=\"timestamp\">%s</span></span>"
	    (replace-regexp-in-string "--" "&#x2013;" value))))

;;;; Underline

(defun org-html-underline (_underline contents info)
  "Transcode UNDERLINE from Org to HTML.
CONTENTS is the text with underline markup.  INFO is a plist
holding contextual information."
  (format (or (cdr (assq 'underline (plist-get info :html-text-markup-alist)))
	      "%s")
	  contents))

;;;; Verbatim

(defun org-html-verbatim (verbatim _contents info)
  "Transcode VERBATIM from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual
information."
  (format (or (cdr (assq 'verbatim (plist-get info :html-text-markup-alist))) "%s")
	  (org-html-encode-plain-text (org-element-property :value verbatim))))

;;;; Verse Block

(defun org-html-verse-block (_verse-block contents info)
  "Transcode a VERSE-BLOCK element from Org to HTML.
CONTENTS is verse block contents.  INFO is a plist holding
contextual information."
  (format "<p class=\"verse\">\n%s</p>"
	  ;; Replace leading white spaces with non-breaking spaces.
	  (replace-regexp-in-string
	   "^[ \t]+" (lambda (m) (org-html--make-string (length m) "&#xa0;"))
	   ;; Replace each newline character with line break.  Also
	   ;; remove any trailing "br" close-tag so as to avoid
	   ;; duplicates.
	   (let* ((br (org-html-close-tag "br" nil info))
		  (re (format "\\(?:%s\\)?[ \t]*\n" (regexp-quote br))))
	     (replace-regexp-in-string re (concat br "\n") contents)))))


;;; Filter Functions

(defun org-html-final-function (contents _backend info)
  "Filter to indent the HTML and convert HTML entities."
  (with-temp-buffer
    (insert contents)
    (set-auto-mode t)
    (when (plist-get info :html-indent)
      (indent-region (point-min) (point-max)))
    (buffer-substring-no-properties (point-min) (point-max))))


;;; End-user functions

;;;###autoload
(defun org-html-export-as-html
  (&optional async subtreep visible-only body-only ext-plist)
  "Export current buffer to an HTML buffer.

If narrowing is active in the current buffer, only export its
narrowed part.

If a region is active, export that region.

A non-nil optional argument ASYNC means the process should happen
asynchronously.  The resulting buffer should be accessible
through the `org-export-stack' interface.

When optional argument SUBTREEP is non-nil, export the sub-tree
at point, extracting information from the headline properties
first.

When optional argument VISIBLE-ONLY is non-nil, don't export
contents of hidden elements.

When optional argument BODY-ONLY is non-nil, only write code
between \"<body>\" and \"</body>\" tags.

EXT-PLIST, when provided, is a property list with external
parameters overriding Org default settings, but still inferior to
file-local settings.

Export is done in a buffer named \"*Org HTML Export*\", which
will be displayed when `org-export-show-temporary-export-buffer'
is non-nil."
  (interactive)
  (org-export-to-buffer 'html "*Org HTML Export*"
    async subtreep visible-only body-only ext-plist
    (lambda () (set-auto-mode t))))

;;;###autoload
(defun org-html-convert-region-to-html ()
  "Assume the current region has Org syntax, and convert it to HTML.
This can be used in any buffer.  For example, you can write an
itemized list in Org syntax in an HTML buffer and use this command
to convert it."
  (interactive)
  (org-export-replace-region-by 'html))

;;;###autoload
(defun org-html-export-to-html
  (&optional async subtreep visible-only body-only ext-plist)
  "Export current buffer to a HTML file.

If narrowing is active in the current buffer, only export its
narrowed part.

If a region is active, export that region.

A non-nil optional argument ASYNC means the process should happen
asynchronously.  The resulting file should be accessible through
the `org-export-stack' interface.

When optional argument SUBTREEP is non-nil, export the sub-tree
at point, extracting information from the headline properties
first.

When optional argument VISIBLE-ONLY is non-nil, don't export
contents of hidden elements.

When optional argument BODY-ONLY is non-nil, only write code
between \"<body>\" and \"</body>\" tags.

EXT-PLIST, when provided, is a property list with external
parameters overriding Org default settings, but still inferior to
file-local settings.

Return output file's name."
  (interactive)
  (let* ((extension (concat "." (or (plist-get ext-plist :html-extension)
				    org-html-extension
				    "html")))
	 (file (org-export-output-file-name extension subtreep))
	 (org-export-coding-system org-html-coding-system))
    (org-export-to-file 'html file
      async subtreep visible-only body-only ext-plist)))

;;;###autoload
(defun org-html-publish-to-html (plist filename pub-dir)
  "Publish an org file to HTML.

FILENAME is the filename of the Org file to be published.  PLIST
is the property list for the given project.  PUB-DIR is the
publishing directory.

Return output file name."
  (org-publish-org-to 'html filename
		      (concat "." (or (plist-get plist :html-extension)
				      org-html-extension
				      "html"))
		      plist pub-dir))


(provide 'ox-html)

;; Local variables:
;; generated-autoload-file: "org-loaddefs.el"
;; End:

;;; ox-html.el ends here