Wikilinks, title before pipe

Wikilinks can have one of the following forms:

[[https://example.org]]
[[title|https://example.org]]
[[name of page]]
[[title|name of page]]

With this version of wikilinks, the title comes before the pipe.

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[[https://example.org]]

<p><a href="https://example.org" data-wikilink="true">https://example.org</a></p>

[[https://example.org|https://example.org]]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <wikilink destination="https://example.org" embed="false">
      <text xml:space="preserve">https://example.org</text>
    </wikilink>
  </paragraph>
</document>

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[[title|https://example.org]]

<p><a href="https://example.org" data-wikilink="true">title</a></p>

[[title|https://example.org]]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <wikilink destination="https://example.org" embed="false">
      <text xml:space="preserve">title</text>
    </wikilink>
  </paragraph>
</document>

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[[Name of page]]

<p><a href="Name%20of%20page" data-wikilink="true">Name of page</a></p>

[[Name of page|Name%20of%20page]]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <wikilink destination="Name of page" embed="false">
      <text xml:space="preserve">Name of page</text>
    </wikilink>
  </paragraph>
</document>

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[[Title|Name of page]]

<p><a href="Name%20of%20page" data-wikilink="true">Title</a></p>

[[Title|Name%20of%20page]]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <wikilink destination="Name of page" embed="false">
      <text xml:space="preserve">Title</text>
    </wikilink>
  </paragraph>
</document>

Regular links should still work!

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[Title](Name%20of%20page)

<p><a href="Name%20of%20page">Title</a></p>

[Title](Name%20of%20page)

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <link destination="Name%20of%20page" title="">
      <text xml:space="preserve">Title</text>
    </link>
  </paragraph>
</document>

HTML entities are recognized both in the name of page and in the link title.

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[[&#xDC;ber &amp;nbsp;|Gesch&uuml;tztes Leerzeichen]]

<p><a href="Gesch%C3%BCtztes%20Leerzeichen" data-wikilink="true">Über &amp;nbsp;</a></p>

[[Über \&nbsp;|Geschütztes%20Leerzeichen]]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <wikilink destination="Geschütztes Leerzeichen" embed="false">
      <text xml:space="preserve">Über &amp;nbsp;</text>
    </wikilink>
  </paragraph>
</document>

Escaping characters is supported

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[[foo\[\]bar|https://example.org]]

<p><a href="https://example.org" data-wikilink="true">foo[]bar</a></p>

[[foo\[\]bar|https://example.org]]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <wikilink destination="https://example.org" embed="false">
      <text xml:space="preserve">foo[]bar</text>
    </wikilink>
  </paragraph>
</document>

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[[Name \[of\] page]]

<p><a href="Name%20%5Bof%5D%20page" data-wikilink="true">Name [of] page</a></p>

[[Name \[of\] page|Name%20[of]%20page]]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <wikilink destination="Name [of] page" embed="false">
      <text xml:space="preserve">Name [of] page</text>
    </wikilink>
  </paragraph>
</document>

Emphasis or other inline markdown is not supported

$ comrak -e wikilinks-title-before-pipe -t commonmark -t xml

[[Name _of_ page]]

<p><a href="Name%20_of_%20page" data-wikilink="true">Name _of_ page</a></p>

[[Name \_of\_ page|Name%20_of_%20page]]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <paragraph>
    <wikilink destination="Name _of_ page" embed="false">
      <text xml:space="preserve">Name _of_ page</text>
    </wikilink>
  </paragraph>
</document>