[css-lists-3] Rewrite counter() section to be more author-friendly, drop 'none' value to match CSS2 w3c#4163

Author: fantasai

css-lists-3/Overview.bs

@@ -815,7 +815,7 @@ Nested Counters and Scope</h3>
 	This is important for situations like lists in HTML,
 	where lists can be nested inside lists to arbitrary depth:
 	it would be impossible to define uniquely named counters for each level.
-	The ''counter()'' function only retrieves the innermost counter of a given name on the element,
+	The ''counter()'' function only retrieves the [=innermost=] counter of a given name on the element,
 	whereas the ''counters()'' function uses all counters of a given name that contain the element.
 
 	The <dfn lt="counter scope" local-lt="scope">scope</dfn> of a [=counter=] therefore
@@ -899,7 +899,7 @@ Creating and Inheriting Counters</h3>
 	an element (representing the counter’s originating element),
 	and an integer (representing the counter’s value).
 	The latest [=counter=] of a given name in that set
-	represents the “innermost” counter of that name.
+	represents the <dfn>innermost</dfn> counter of that name.
 
 <h4 id="inheriting-counters">
 Inheriting Counters</h4>
@@ -1147,34 +1147,47 @@ The Implicit ''list-item'' Counter</h3>
 <h3 id='counter-functions'>
 Outputting Counters: the ''counter()'' and ''counters()'' functions</h3>
 
-	Counters have no visible effect by themselves,
+	[=Counters=] have no visible effect by themselves,
 	but their values can be used
 	with the ''counter()'' and ''counters()'' functions,
-	which represent the counter values as strings or images.
-	Their syntax is:
+	whose [=used values=] represent counter values as strings or images.
+	They are defined as follows:
 
 	<pre>
 		<dfn><<counter>></dfn> = <<counter()>> | <<counters()>>
-		<dfn>counter()</dfn>  =  counter( <<counter-name>>, [ <<counter-style>> | none ]? )
-		<dfn>counters()</dfn> = counters( <<counter-name>>, <<string>>, [ <<counter-style>> | none ]? )
+		<dfn>counter()</dfn>  =  counter( <<counter-name>>, <<counter-style>>? )
+		<dfn>counters()</dfn> = counters( <<counter-name>>, <<string>>, <<counter-style>>? )
 	</pre>
 
-	For both functions, the first argument represents the name of a counter,
-	and if the last argument is omitted it defaults to ''decimal''.
+	where <<counter-style>> specifies the [=counter style=]
+	for <a lt="generate a counter representation">generating a representation</a>
+	of the named counter(s)
+	as defined in [[!css-counter-styles-3]] and
 
-	The used value of ''counter()'' is obtained as follows:
+	<dl>
+		<dt>counter()
+		<dd>
+			Represents the value of the [=innermost=] [=counter=]
+			in the element’s [=CSS counters set=]
+			named <<counter-name>>
+			using the [=counter style=] named <<counter-style>>.
 
-	<ul>
-		<li>
-			If the second argument to the function is <css>none</css>,
-			the function represents the empty string.
-
-		<li>
-			Otherwise, the function represents the string returned when one <a lt="generate a counter representation">generates a counter representation</a>
-			for the value of the innermost counter of that name on the element
-			(or ''0'' if the element has no counter of that name)
-			using the <<counter-style>> specified by the second argument.
-	</ul>
+		<dt>counters()
+		<dd>
+			Represents the values of all the [=counters=]
+			in the element’s [=CSS counters set=]
+			named <<counter-name>>
+			using the [=counter style=] named <<counter-style>>,
+			sorted in outermost-first to [=innermost=]-last order
+			and joined by the specified <<string>>.
+	</dl>
+
+	In both cases,
+	if the <<counter-style>> argument is omitted it defaults to ''decimal''.
+
+	If no [=counter=] named <<counter-name>> exists
+	on an element where ''counter()'' or ''counters()'' is used,
+	one is first [=instantiated=] with a starting value of ''0''.
 
 	<div class="example">
 		<pre>
@@ -1195,37 +1208,6 @@ Outputting Counters: the ''counter()'' and ''counters()'' functions</h3>
 		</pre>
 	</div>
 
-	The used value of ''counters()'' is obtained as follows:
-
-	<ul>
-		<li>
-			If the third argument to the function is <css>none</css>,
-			the function represents the empty string.
-
-		<li>
-			Otherwise, if the element has no counters of that name,
-			the function represents the string returned when one <a lt="generate a counter representation">generates a counter representation</a>
-			for ''0''
-			using the <<counter-style>> specified by the third argument.
-
-		<li>
-			Otherwise, if the element has a single counter of that name,
-			the function represents the string returned when one <a lt="generate a counter representation">generates a counter representation</a>
-			for that counter's value
-			using the <<counter-style>> specified by the third argument.
-
-		<li>
-			Otherwise,
-			<a>generate a counter representation</a>
-			for the values of all counters of the given name on the element
-			using the <<counter-style>> specified by the third argument.
-			Sort the resulting strings by the nesting depth of the counters they were generated from,
-			with the outermost counter first and the innermost last.
-			Join the list into a single string,
-			inserting the <<string>> specified by the second argument between each item in the list.
-			The function represents the string thus produced.
-	</ul>
-
 	<div class='example'>
 		The following example shows a simple use of the ''counters()'' function: