Skip to content

Commit

Permalink
Rewrite section about semantics/annotation/annotation-xml
Browse files Browse the repository at this point in the history 
w3c/mathml#100
  • Loading branch information
@fred-wang
fred-wang committed Jun 18, 2019
1 parent 73cb87f commit d23cff4
Show file tree
Hide file tree
Showing 2 changed files with 63 additions and 72 deletions.
132 changes: 60 additions & 72 deletions index.html
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2287,9 +2287,18 @@ <h3>Enlivening Expressions</h3>
</p>
<p>
The <code>&lt;maction&gt;</code> element accepts the attributes described
in <a href="#global-attributes"></a>.
The <code>actiontype</code> and <code>selection</code> attributes are
also accepted but they do not have any effect.
in <a href="#global-attributes"></a> as well as the following
attributes:
</p>
<ul>
<li><code>actiontype</code></li>
<li><code>selection</code></li>
</ul>
<p>
The <dfn>actiontype</dfn> and <dfn>selection</dfn> attributes are
not taken into account in the present specification but may be used
by authors to implement custom actions on the
<code>&lt;maction&gt;</code> element.
</p>
<p>
The layout algorithm of the <code>&lt;maction&gt;</code> element
Expand All @@ -2312,71 +2321,56 @@ <h3>Semantics and Presentation</h3>
The
<dfn><code>&lt;semantics&gt;</code></dfn>
element is the container element that associates
annotations with a MathML expression. The semantics element has as its first
child the expression to be annotated. Any MathML expression may appear as the
first child of the semantics element. Subsequent annotation and annotation-xml
children enclose the annotations. An annotation represented in XML is enclosed
in an
<dfn><code>&lt;annotation-xml&gt;</code></dfn>
element. An annotation represented in character data
is enclosed in an
<dfn><code>&lt;annotation&gt;</code></dfn>
element.
annotations with a MathML expression. Typically, the
<code>&lt;semantics&gt;</code> element has as its first child a
MathML expression to be annotated while subsequent children represent
text annotations within an <dfn><code>&lt;annotation&gt;</code></dfn>
element, or more complex markup annotations within
an <dfn><code>&lt;annotation-xml&gt;</code></dfn> element.
</p>
<p>
User agents must display at most one of the child of a <code>&lt;semantics&gt;</code> element.
For example, they may always display the first child (if any) or may use this
more advanced algorithm to determine a visible child:
The <code>&lt;semantics&gt;</code> element accepts the attributes
described in <a href="#global-attributes"></a>. Its layout algorithm
is the same as the <a><code>&lt;mrow&gt;</code></a> element.
The <a href="#user-agent-stylesheet">user agent stylesheet</a>
must contain the following rule in order to only render the annotated
MathML expression:
</p>
<ol>
<li>
<p>
If the <code>&lt;semantics&gt;</code> element has a first child that is any of the
MathML elements (other than <code>&lt;annotation&gt;</code> and <code>&lt;annotation-xml&gt;</code>)
whose rendering is described in this document then use it as the visible
child and stop.
</p>
</li>
<li>
<p>
Otherwise, check the children of the <code>&lt;semantics&gt;</code> element in the DOM
order to try and find the first child that is
</p>
<ol>
<li>
<p>
Either an <code>&lt;annotation&gt;</code> without any <code>src</code> attribute.
</p>
</li>
<li>
<p>
Or an <code>&lt;annotation-xml&gt;</code> without any <code>src</code> attribute and
with an <code>encoding</code> attribute that has value
<code>"application/mathml-presentation+xml"</code>,
<code>"MathML-Presentation"</code>,
<code>"image/svg+xml"</code>,
<code>"SVG1.1"</code>,
<code>"application/xhtml+xml"</code> or
<code>"text/html"</code>.
</p>
</li>
</ol>
</li>
<li>Otherwise, fallback to the first child (if any).</li>
<li>Otherwise, the <code>&lt;semantics&gt;</code> element is empty and the visible child is
undetermined.
</li>
</ol>
<pre data-include="user-agent-stylesheet/semantics.css"></pre>
<p>
The <code>&lt;annotation-xml&gt;</code> and
<code>&lt;annotation&gt;</code> element accepts the attributes
described in <a href="#global-attributes"></a> as well as the
following attribute:
</p>
<ul>
<li><code>encoding</code></li>
</ul>
<p>
For the layout algorithm described in this document, the
<code>&lt;annotation-xml&gt;</code> element must be treated the same as the <code>&lt;mrow&gt;</code> element,
the <code>&lt;annotation&gt;</code> element must be treated the same as the <code>&lt;mtext&gt;</code>
element. The <code>&lt;semantics&gt;</code> element must be treated the same as an
<code>&lt;mrow&gt;</code> element containing only its visible child. If it is undetermined,
the user agent may treat the <code>&lt;semantics&gt;</code> element as an
empty <code>&lt;mrow&gt;</code> element or as an <code>&lt;merror&gt;</code> element with some error message
indicating invalid markup.
The <dfn>encoding</dfn> attribute is not taken into account in the
present specification but it is intended to distinguish annotations
for <a data-cite="HTML#html-integration-point">HTML integration point</a>, clipboard copy, alternative rendering etc
</p>
<p>
The layout algorithm of the <code>&lt;annotation-xml&gt;</code>
element is the same as the <a><code>&lt;mrow&gt;</code></a> element.
The layout algorithm of the <code>&lt;annotation&gt;</code>
element is the same as the <a><code>&lt;mtext&gt;</code></a> element.
</p>
<div class="note">
CSS can be used to render alternative annotations e.g.
<pre class="css">
/* Hide the annotated child. */
semantics > :first-child { display: none; }
/* Show all text annotations. */
semantics > annotation { display: block; }
/* Show all HTML annotations. */
semantics > annotation-xml[encoding="text/html" i],
semantics > annotation-xml[encoding="application/xhtml+xml" i] {
display: block;
}
</pre>
</div>
</section>
</section>
<section class="normative">
Expand Down Expand Up @@ -2564,17 +2558,11 @@ <h2>User Agent Stylesheet</h2>
/* The &lt;math&gt; element */
<span data-include="user-agent-stylesheet/math.css"></span>
/* &lt;mrow&gt;-like elements */
<span data-include="user-agent-stylesheet/maction.css"></span><span data-include="user-agent-stylesheet/merror.css"></span><span data-include="user-agent-stylesheet/mphantom.css"></span>
<span data-include="user-agent-stylesheet/semantics.css"></span><span data-include="user-agent-stylesheet/maction.css"></span><span data-include="user-agent-stylesheet/merror.css"></span><span data-include="user-agent-stylesheet/mphantom.css"></span>
/* Tables */
<span data-include="user-agent-stylesheet/mtable.css"></span>
<span data-include="user-agent-stylesheet/mtable-frame.css"></span>
<span data-include="user-agent-stylesheet/mtr.css"></span>
<span data-include="user-agent-stylesheet/mtd.css"></span>
<span data-include="user-agent-stylesheet/mtable.css"></span><span data-include="user-agent-stylesheet/mtable-frame.css"></span><span data-include="user-agent-stylesheet/mtr.css"></span><span data-include="user-agent-stylesheet/mtd.css"></span>
/* Other rules for scriptlevel and displastyle */
<span data-include="user-agent-stylesheet/displaystyle.css"></span>
<span data-include="user-agent-stylesheet/mfrac.css"></span>
<span data-include="user-agent-stylesheet/mroot.css"></span>
<span data-include="user-agent-stylesheet/scripts.css"></span>
<span data-include="user-agent-stylesheet/displaystyle.css"></span><span data-include="user-agent-stylesheet/mfrac.css"></span><span data-include="user-agent-stylesheet/mroot.css"></span><span data-include="user-agent-stylesheet/scripts.css"></span>
</pre>
</section>
<section>
Expand Down
3 changes: 3 additions & 0 deletions user-agent-stylesheet/semantics.css
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
semantics > :not(:first-child) {
display: none;
}

0 comments on commit d23cff4

Please sign in to comment.