[css-text-4] Split text-space-collapse into one inherited and one non-inherited property.

Author: fantasai

css-text-4/Overview.bs

@@ -25,7 +25,7 @@ Transforming Text</h2>
 <h2 id="white-space-processing">
 White Space Processing</h2>
 
-	<p class="note">Add final level 3 tab-size</p>
+	<p class="note">Add final level 3 tab-size and processing details</p>
 
 <h3 id="white-space-collapsing">
 White Space Collapsing: the 'text-space-collapse' property</h3>
@@ -34,7 +34,7 @@ White Space Collapsing: the 'text-space-collapse' property</h3>
 
 	<pre class="propdef">
 	Name: text-space-collapse
-	Value: collapse | discard | [ [preserve | preserve-breaks] && [ trim-inner || consume-before || consume-after ]
+	Value: collapse | discard | preserve | preserve-breaks
 	Initial: collapse
 	Applies to: all elements
 	Inherited: yes
@@ -48,8 +48,7 @@ White Space Collapsing: the 'text-space-collapse' property</h3>
 	This property declares whether and how
 	<a href="#white-space-processing">white space</a> inside the element is
 	collapsed. Values have the following meanings, which must be interpreted
-	according to the <a href="#white-space-rules">white space processing
-	rules</a>:
+	according to the white space processing rules:
 
 	<dl dfn-for=text-space-collapse dfn-type=value>
 		<dt><dfn>collapse</dfn>
@@ -73,7 +72,46 @@ White Space Collapsing: the 'text-space-collapse' property</h3>
 		<dd>
 			This value directs user agents to "discard" all white space in the
 			element.
+			Issue: Does this preserve line break opportunities or no? Do we need a "hide" value?
+	</dl>
+
+	<div class="example">
+		
+		The following style rules implement MathML's white space processing:
+
+		<pre>
+			@namespace m "http://www.w3.org/1998/Math/MathML";
+			m|* {
+				text-space-collapse: discard;
+			}
+			m|mi, m|mn, m|mo, m|ms, m|mtext {
+				text-space-collapse: trim-inner;
+			}
+		</pre>
+	</div>
+
+	<p class="issue">This section is still under discussion and may change in future drafts.</p>
+
+<h3 id="white-space-trim">
+White Space Trimming: the 'text-space-trim' property</h3>
+
+	<pre class="propdef">
+	Name: text-space-trim
+	Value: none | trim-inner || consume-before || consume-after
+	Initial: collapse
+	Applies to: all elements
+	Inherited: no
+	Percentages: n/a
+	Computed value: as specified
+	Media: visual
+	</pre>
+
+	This property allows authors to specify trimming behavior
+	at the beginning and end of a box.
+	Values have the following meanings,
+	which must be interpreted according to the white space processing rules:
 
+	<dl dfn-for=text-space-trim dfn-type=value>
 		<dt><dfn>trim-inner</dfn>
 		<dd>
 			For block containers this value directs UAs to discard all whitespace
@@ -95,22 +133,6 @@ White Space Collapsing: the 'text-space-collapse' property</h3>
 			immediately after the end of the element.
 	</dl>
 
-	<div class="example">
-		
-		The following style rules implement MathML's white space processing:
-
-		<pre>
-			@namespace m "http://www.w3.org/1998/Math/MathML";
-			m|* {
-				text-space-collapse: discard;
-			}
-			m|mi, m|mn, m|mo, m|ms, m|mtext {
-				text-space-collapse: trim-inner;
-			}
-		</pre>
-	</div>
-
-
 	<div class="example">
 		<p>The following style rules render DT elements as a comma-separated list:
 		<pre>
@@ -119,13 +141,6 @@ White Space Collapsing: the 'text-space-collapse' property</h3>
 		</pre>
 	</div>
 
-	<p class="issue">It's been pointed out that ''trim-inner'', ''consume-before'',
-	and ''consume-after'' won't work well because 'text-space-collapse' is
-	inherited, meaning that inserting a &lt;span> or &gt;div> would cause more
-	white space to be removed than otherwise.
-
-	<p class="note">Add final level 3 details</p>
-
 <h2 id="line-breaking">
 Line Breaking and Word Boundaries</h2>