Details Formatter

%%(details title="summary" open=1)%%

<details open>
  <summary>System Requirements</summary>
  <p>Requires a computer running an operating system. The computer
  must have some memory and ideally some kind of long-term storage.
  An input device as well as some form of output device is
  recommended.</p>
</details>

formatter/highlight/details.php^[link1]

<?php

/*
    % %(details
        [title="Title"]
        [open=0|1]
        )
    content
    % %
*/

if (!isset($options['title']))        $options['title']    = null;
if (!isset($options['open']))        $options['open']    = 0;

$title    = $options['title'] ?? $this->_t('ShowHideDetails');
$open    = $options['open'] ? ' open' : '';

echo    '<ignore><details' . $open . '>' . "\n";
echo    ($title
            ? '<summary>' . Ut::html($title) . '</summary>' . "\n"
            : '');
include Ut::join_path(FORMATTER_DIR, 'wiki.php');
echo    "</details></ignore>\n";

Summary

The HTML Details Element (<details>) creates a disclosure widget in which information is visible only when the widget is toggled into an "open" state. A summary or label can be provided using the <summary> element.

A disclosure widget is typically presented onscreen using a small triangle which rotates (or twists) to indicate open/closed status, with a label next to the triangle. If the first child of the <details> element is a <summary>, the contents of the <summary> element are used as the label for the disclosure widget.

Remarks

The Formatter does not support nesting. A formatter cannot invoke another formatter by design.
- formatter + wrapper
- it can be done via inline HTML, but this is rather inconvenient because you can't nest wiki syntax in between the <details> tags, the HTML SAX parser would close your <details> tag with </details> in advance

Links

[link1] https://bitbucket.org/wackowiki/wackowiki/src/master/src/formatter/highlight/details.php
[link2] http://html5doctor.com/the-details-and-summary-elements/
[link3] https://developer.mozilla.org/en-US/docs/Web/HTML/Element/details