[css-text] Anchorify 'white space'. Clarify difference between document white space and CSS syntactic white space.

--HG--
extra : rebase_source : 64f701cc573065ae7d2f5e20ce15119cabcfa46f

Author: fantasai

css-text/Overview.bs

@@ -404,7 +404,7 @@ Languages and Typesetting</h4>
 
     <p>Text transformation happens after <a href="#white-space-rules">white
       space processing</a>, which means that ''full-width'' only transforms
-      U+0020 spaces to U+3000 within preserved white spaces.
+      preserved U+0020 spaces to U+3000.
 
     <p class="note">
       A future level of CSS may introduce the ability to create custom mapping
@@ -458,7 +458,7 @@ Languages and Typesetting</h4>
 
   <p>This property specifies two things:
   <ul>
-    <li>whether and how <a href="#white-space-processing">white space</a> inside the element is collapsed
+    <li>whether and how <i>white space</i> inside the element is collapsed
     <li>whether lines may <i>wrap</i> at unforced <i>soft wrap opportunities</i>
   </ul>
 
@@ -469,22 +469,22 @@ Languages and Typesetting</h4>
 
   <dl dfn-for=white-space dfn-type=value>
     <dt><dfn>normal</dfn></dt>
-    <dd>This value directs user agents to collapse sequences of white space
+    <dd>This value directs user agents to collapse sequences of <i>white space</i>
       into a single character (or <a href="#line-break-transform">in some
       cases</a>, no character).
       Lines may wrap at allowed <i>soft wrap opportunities</i>,
       as determined by the line-breaking rules in effect,
       in order to minimize inline-axis overflow.
     <dt><dfn>pre</dfn></dt>
-    <dd>This value prevents user agents from collapsing sequences of white space.
+    <dd>This value prevents user agents from collapsing sequences of <i>white space</i>.
       <i>Segment breaks</i> such as line feeds and carriage returns are preserved as <i>forced line breaks</i>.
       Lines only break at <i>forced line breaks</i>;
       content that does not fit within the block container overflows it.
     <dt><dfn>nowrap</dfn>
-    <dd>Like ''white-space/normal'', this value collapses white space;
+    <dd>Like ''white-space/normal'', this value collapses <i>white space</i>;
       but like ''pre'', it does not allow wrapping.
     <dt><dfn>pre-wrap</dfn></dt>
-    <dd>Like ''pre'', this value preserves white space;
+    <dd>Like ''pre'', this value preserves <i>white space</i>;
       but like ''white-space/normal'', it allows wrapping.
     <dt><dfn>pre-line</dfn></dt>
     <dd>Like ''white-space/normal'', this value collapses consecutive spaces and allows wrapping,
@@ -542,12 +542,12 @@ Languages and Typesetting</h4>
     for details on how white space collapses. An informative summary of
     collapsing (''white-space/normal'' and ''nowrap'') is presented below:
     <ul>
-      <li>A sequence of segment breaks and other white space between two
+      <li>A sequence of segment breaks and other <i>white space</i> between two
         Chinese, Japanese, or Yi characters collapses into nothing.
       <li>A zero width space before or after a white space sequence
-        containing a segment break causes the entire sequence of white space
+        containing a segment break causes the entire sequence of <i>white space</i>
         to collapse into a zero width space.
-      <li>Otherwise, consecutive white space collapses into a single space.
+      <li>Otherwise, consecutive <i>white space</i> collapses into a single space.
     </ul>
 
   <p>See <a href="#line-breaking">Line Breaking</a>
@@ -575,20 +575,21 @@ Languages and Typesetting</h4>
     <code>RECORD-START</code> and <code>RECORD-END</code> tokens.
     For CSS processing, each document language&ndash;defined segment break,
     CRLF sequence (U+000D U+000A), carriage return (U+000D), and line feed (U+000A)
-    in the text is treated as a <dfn>segment break</dfn>,
+    in the text is treated as a <dfn export>segment break</dfn>,
     which is then interpreted for rendering as specified by the 'white-space' property.
 
-  <p class="note">Note that the document parser may have not only normalized
-    any segment breaks, but also collapsed other space characters or
+  <p class="note">Note that the document parser may have
+    not only normalized any <i>segment breaks</i>,
+    but also collapsed other space characters or
     otherwise processed white space according to markup rules. Because CSS
     processing occurs <em>after</em> the parsing stage, it is not possible
     to restore these characters for styling. Therefore, some of the
     behavior specified below can be affected by these limitations and
     may be user agent dependent.</p>
 
   <p class="note">Note that anonymous blocks consisting entirely of
-    <i>collapsible</i> white space are removed from the rendering tree.
-    Thus any such white space surrounding a block-level element is collapsed away.
+    <i>collapsible</i> <i>white space</i> are removed from the rendering tree.
+    Thus any such <i>white space</i> surrounding a block-level element is collapsed away.
     See [[CSS21]] section
     <a href="http://www.w3.org/TR/CSS21/visuren.html#anonymous">9.2.2.1</a></p>
 
@@ -601,8 +602,16 @@ Languages and Typesetting</h4>
   <h3 id="white-space-rules">
     The White Space Processing Rules</h3>
 
-    <p>White space processing affects only spaces (U+0020), tabs (U+0009),
-      and <a href="#segment-normalization">segment breaks</a>.
+    <p>White space processing in CSS affects only
+      the <dfn export title="white space|white space characters| document white space|document white space characters">document white space characters</dfn>:
+      spaces (U+0020), tabs (U+0009), and <a href="#white-space-processing">segment breaks</a>.
+
+    <p class="note">
+      Note that the set of characters considered <i>document white space</i> (part of the document content)
+      and that considered syntactic white space (part of the CSS syntax)
+      are not necessarily identical.
+      However, since both include spaces (U+0020), tabs (U+0009), line feeds (U+000A), and carriage returns (U+000D)
+      most authors won't notice any differences.
 
     <h4 id="white-space-phase-1">Phase I: Collapsing and Transformation</h4>
 
@@ -615,12 +624,12 @@ Languages and Typesetting</h4>
     <ul>
     <li id="collapse"><p>If 'white-space' is set to
       ''white-space/normal'', ''nowrap'', or ''pre-line'',
-      white space characters are considered <dfn>collapsible</dfn>
+      white space characters are considered <dfn export title="collapsible white space|collapsible">collapsible</dfn>
       and are processed by performing the following steps:</p>
       <ol>
         <li>All spaces and tabs immediately preceding or following a segment
           break are removed.</li>
-        <li>Segment breaks are transformed for
+        <li><i>Segment breaks</i> are transformed for
           rendering according to the <a href="#line-break-transform">segment break transformation rules</a>.
         </li>
         <li>Every tab is converted to a space (U+0020).</li>