XML Formatting Fails for Elements with Dots in Names

[commonsguy]

If you have an XML element with dots in the element name, at least for the root element, that element does not get syntax highlighting applied.

<android.support.v7.widget.CardView
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:cardview="http://schemas.android.com/apk/res-auto"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_margin="4dp"
  cardview:cardCornerRadius="4dp"/>

Attached, please find a ZIP file containing two PrismJS samples. The not-working/ one uses an element name of android.support.v7.widget.CardView, and that element does not get syntax-highlighted (though child elements do). The working/ one removes the dots (for a fictitious androidsupportv7widgetCardView element), and that element does get syntax-highlighted. The results are reproducible on Firefox 44, Chromium 48, and the Android 6.0 WebView, at minimum.
prismjs-bug.zip

Let me know if you need additional information -- thanks!

[LeaVerou]

Should we change the regexp in markup to include periods? Is there anything that could break if we do?

[zeitgeist87]

The XML specification explicitly allows the . character for tag names:
https://www.w3.org/TR/REC-xml/#NT-Name

But HTML only allows alphanumeric ASCII characters as tag names:
https://www.w3.org/TR/html5/syntax.html#syntax-tag-name

Since Prism is not a parser it should be more permissive and allow the . character, but I don't know if that would cause anything to break...

[Golmote]

Well we do have tests now, don't we?

[zeitgeist87]

Well we do have tests now, don't we?

Allowing the . character will break the following Textile-language test:

!<foo.png! !>bar.jpg!

This is recognized as a HTML-tag: <foo.png! !>. Why does Textile extend Markup anyway?

[Golmote]

Why does Textile extend Markup anyway?

Because it allows HTML:

You can certainly use HTML tags inside your Textile documents.
I am <b>very</b> serious.

http://redcloth.org/hobix.com/textile/#writing-in-textile

[Golmote]

This is recognized as a HTML-tag: <foo.png! !>

Should we allow the exclamation point though?

[zeitgeist87]

This is recognized as a HTML-tag: <foo.png! !>
Should we allow the exclamation point though?

If I disallow the exclamation point, then the following line fails:

|_. foo |<_. bar |>_. baz |

because <_. bar |> is recognized as the tag _., with the two boolean attributes bar and |.

Since HTML only allows alpha-numeric tags ànyway we could do this:

Prism.languages.textile.tag.pattern = /<\/?(?!\d)[a-z0-9]+(?:\s+[^\s>\/=]+(?:=(?:("|')(?:\\\1|\\?(?!\1)[\w\W])*\1|[^\s'">=]+))?)*\s*\/?>/i;