[css-syntax] Resolve a "must" vs. "should not" define an environment encoding.

Author: SimonSapin

css-syntax/Overview.html

@@ -117,8 +117,7 @@ <h2 class="no-num no-toc no-ref heading settled heading" id=contents><span class
 Error Handling</a></ul><li><a href=#tokenizing-and-parsing><span class=secno>3</span>
 Tokenizing and Parsing CSS</a><ul class=toc><li><a href=#parsing-overview><span class=secno>3.1</span>
 Overview of the Parsing Model</a><li><a href=#input-byte-stream><span class=secno>3.2</span>
-The input byte stream</a><li><a href=#environment-encoding><span class=secno>3.3</span>
-Environment encoding</a><li><a href=#input-preprocessing><span class=secno>3.4</span>
+The input byte stream</a><li><a href=#input-preprocessing><span class=secno>3.3</span>
 Preprocessing the input stream</a></ul><li><a href=#tokenization><span class=secno>4</span>
 Tokenization</a><ul class=toc><li><a href=#token-diagrams><span class=secno>4.1</span>
 Token Railroad Diagrams</a><li><a href=#tokenizer-definitions><span class=secno>4.2</span>
@@ -496,14 +495,9 @@ <h3 class="heading settled heading" data-level=3.2 id=input-byte-stream><span cl
 			and thus maximizes the likelihood of it being implemented correctly.
 
 		<li>
-			Otherwise, if an <a data-link-type=dfn href=#environment-encoding0 title="environment encoding">environment encoding</a> is provided by the referring document,
+			Otherwise, if an <a data-link-type=dfn href=#environment-encoding title="environment encoding">environment encoding</a> is provided by the referring document,
 			use that as the fallback encoding.
 
-<p>			Note that the concept of <a data-link-type=dfn href=#environment-encoding0 title="environment encoding">environment encoding</a> is required for legacy purposes
-			for HTML and XML.
-			New types of referring documents <strong>should not</strong> provide an <a data-link-type=dfn href=#environment-encoding0 title="environment encoding">environment encoding</a>,
-			so the stylesheet defaults to UTF-8 instead in the absence of more explicit information.
-
 		<li>
 			Otherwise, use <code>utf-8</code> as the fallback encoding.
 	</ol>
@@ -526,21 +520,22 @@ <h3 class="heading settled heading" data-level=3.2 id=input-byte-stream><span cl
 
 <pre>@charset "utf-8";</pre>	</div>
 
-<h3 class="heading settled heading" data-level=3.3 id=environment-encoding><span class=secno>3.3 </span><span class=content>
-Environment encoding</span><a class=self-link href=#environment-encoding></a></h3>
-
 <p>	Document languages that refer to CSS stylesheets that are decoded from bytes
-	must define an <dfn data-dfn-type=dfn data-export="" id=environment-encoding0>environment encoding<a class=self-link href=#environment-encoding0></a></dfn> for each such stylesheet,
+	may define an <dfn data-dfn-type=dfn data-export="" id=environment-encoding>environment encoding<a class=self-link href=#environment-encoding></a></dfn> for each such stylesheet,
 	which is used as a fallback when other encoding hints are not available or can not be used.
 
+<p>	The concept of <a data-link-type=dfn href=#environment-encoding title="environment encoding">environment encoding</a> only exists for compatibility with legacy content.
+	New formats and new linking mechanisms <b>should not</b> provide an <a data-link-type=dfn href=#environment-encoding title="environment encoding">environment encoding</a>,
+	so the stylesheet defaults to UTF-8 instead in the absence of more explicit information.
+
 <p class=note>	Note: <a data-biblio-type=informative data-link-type=biblio href=#html title=html>[HTML]</a> defines <a href=http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#link-type-stylesheet>the environment encoding for <code>&lt;link rel=stylesheet&gt;</code></a>.
 
 <p class=note>	Note: <a data-biblio-type=informative data-link-type=biblio href=#cssom title=cssom>[CSSOM]</a> defines <a href=http://dev.w3.org/csswg/cssom/#requirements-on-user-agents-implementing-the-xml-stylesheet-processing-instruction>the environment encoding for <code>&lt;xml-stylesheet?&gt;</code></a>.
 
 <p class=note>	Note: <a data-biblio-type=informative data-link-type=biblio href=#css3cascade title=css3cascade>[CSS3CASCADE]</a> defines <a href=http://dev.w3.org/csswg/css-cascade/#at-ruledef-import>the environment encoding for <code>@import</code></a>.
 
 
-<h3 class="heading settled heading" data-level=3.4 id=input-preprocessing><span class=secno>3.4 </span><span class=content>
+<h3 class="heading settled heading" data-level=3.3 id=input-preprocessing><span class=secno>3.3 </span><span class=content>
 Preprocessing the input stream</span><a class=self-link href=#input-preprocessing></a></h3>
 
 <p>	The input stream consists of the <a data-link-type=dfn href=#code-point title="code points">code points</a>
@@ -4698,7 +4693,7 @@ <h3 class="heading settled heading" data-level=10.2 id=changes-WD-20130919><span
 
 <p>	<ul>
 		<li>
-			The concept of <a data-link-type=dfn href=#environment-encoding0 title="environment encoding">environment encoding</a> was added.
+			The concept of <a data-link-type=dfn href=#environment-encoding title="environment encoding">environment encoding</a> was added.
 			The behavior does not change,
 			but some of the definitions should be moved to the relevant specs.
 	</ul>
@@ -5048,7 +5043,7 @@ <h2 class="no-num no-ref heading settled heading" id=index><span class=content>
 <li>&lt;dimension-token&gt;, <a href=#typedef-dimension-token title="section 4">4</a>
 <li>ending token, <a href=#ending-token title="section 5.4.7">5.4.7</a>
 <li>end of the range, <a href=#unicode-range-end title="section 4">4</a>
-<li>environment encoding, <a href=#environment-encoding0 title="section 3.3">3.3</a>
+<li>environment encoding, <a href=#environment-encoding title="section 3.2">3.2</a>
 <li>EOF code point, <a href=#eof-code-point title="section 4.2">4.2</a>
 <li>&lt;EOF-token&gt;, <a href=#typedef-eof-token title="section 5.2">5.2</a>
 <li>escaping, <a href=#escaping0 title="section 2.1">2.1</a>

css-syntax/Overview.src.html

@@ -335,11 +335,6 @@ <h3 id="input-byte-stream">
 			Otherwise, if an <a>environment encoding</a> is provided by the referring document,
 			use that as the fallback encoding.
 
-			Note that the concept of <a>environment encoding</a> is required for legacy purposes
-			for HTML and XML.
-			New types of referring documents <strong>should not</strong> provide an <a>environment encoding</a>,
-			so the stylesheet defaults to UTF-8 instead in the absence of more explicit information.
-
 		<li>
 			Otherwise, use <code>utf-8</code> as the fallback encoding.
 	</ol>
@@ -363,13 +358,14 @@ <h3 id="input-byte-stream">
 		<pre>@charset "utf-8";</pre>
 	</div>
 
-<h3 id="environment-encoding">
-Environment encoding</h3>
-
 	Document languages that refer to CSS stylesheets that are decoded from bytes
-	must define an <dfn export>environment encoding</dfn> for each such stylesheet,
+	may define an <dfn export>environment encoding</dfn> for each such stylesheet,
 	which is used as a fallback when other encoding hints are not available or can not be used.
 
+	The concept of <a>environment encoding</a> only exists for compatibility with legacy content.
+	New formats and new linking mechanisms <b>should not</b> provide an <a>environment encoding</a>,
+	so the stylesheet defaults to UTF-8 instead in the absence of more explicit information.
+
 	Note: [[HTML]] defines <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#link-type-stylesheet">the environment encoding for <code>&lt;link rel=stylesheet></code></a>.
 
 	Note: [[CSSOM]] defines <a href="http://dev.w3.org/csswg/cssom/#requirements-on-user-agents-implementing-the-xml-stylesheet-processing-instruction">the environment encoding for <code>&lt;xml-stylesheet?></code></a>.