“special characters” should be allowed for anchors.

[tastytea]

% asciidoctor --version
Asciidoctor 2.0.9 [https://asciidoctor.org]
Runtime Environment (ruby 2.4.5p335 (2018-10-18 revision 65137) [x86_64-linux]) (lc:UTF-8 fs:UTF-8 in:UTF-8 ex:UTF-8)

The following document does not convert to the expected HTML5 output.

= Test

anchor:CO₂[]abc

I used the command asciidoctor --backend=html5 --out-file=out.html in.adoc.

According to the W3C Recommendation, the id attribute has to conform only to these rules:

• Must contain at least one character.
• Must not contain any space characters.

There are no other restrictions on what form an ID can take; in particular, IDs can consist of just digits, start with a digit, start with an underscore, consist of just punctuation, etc.

But the output is:

<div class="paragraph">
<p>anchor:CO₂[]abc</p>
</div>

I have similar results with &, %, /, → and anchors starting with a digit. Please allow “special characters” in anchors.

[cirosantilli]

Related: #1540

[mojavelinux]

According to the W3C Recommendation, the id attribute has to conform only to these rules:

Yes, but HTML isn't the only output format for AsciiDoc. Using other characters would lead to invalid DocBook (and likely EPUB 3 too, which still conforms to XML rules in some versions and readers).

[cirosantilli]

One possible solution would be to let it work fine on HTML5 output, but blow up on other outputs.

[mojavelinux]

Right. Agreed. I just wanted to make sure to frame the conversation.