[css-color-4] Use <dashed-ident> for non-predefined colorspaces, fix w3c#4654

Author: svgeesus

css-color-4/Overview.bs

@@ -2081,30 +2081,33 @@ Profiled, Device-dependent Colors</h2>
 
 	<div class='example'>
 		This example specifies four profiled colors:
-		for a standard SWOP-coated CMYK press,
-		for a wide-gamut seven-ink printer,
-		for ProPhoto RGB,
-		and for the display-p3 standard RGB space.
+		two are custom spaces
+		(for a SWOP-coated CMYK press,
+		for a wide-gamut seven-ink printer),
+		the other two are predefined spaces
+		(the ProPhoto RGB,
+		and display-p3 RGB spaces).
 		In each case, the numerical parameters
 		are in the range 0.0 to 1.0
 		(rather than, for example, 0 to 255).
 		<!-- add examples with alpha, and with fallback -->
 		<pre>
-			color: color(swopc 0.0134 0.8078 0.7451 0.3019);
-			color: color(indigo 0.0941 0.6274 0.3372 0.1647 0 0.0706 0.1216);
+			color: color(--swopc 0.0134 0.8078 0.7451 0.3019);
+			color: color(--indigo 0.0941 0.6274 0.3372 0.1647 0 0.0706 0.1216);
 			color: color(prophoto-rgb 0.9137 0.5882 0.4784);
 			color: color(display-p3 0.3804 0.9921 0.1412);
 		</pre>
 
 		The colors not using a <a href="#predefined">predefined</a> colorspace
+		are distinguished by their use of <<dashed-ident>> and
 		also need a matching ''@color-profile'' at-rule
 		somewhere in the stylesheet,
 		to connect the name with the profile data.
 
 		<pre>
-			@color-profile swopc {
+			@color-profile --swopc {
 				src: url('http://example.org/swop-coated.icc');}
-			@color-profile indigo {
+			@color-profile --indigo {
 				src: url('http://example.org/indigo-seven.icc');}
 		</pre>
 	</div>
@@ -2117,7 +2120,7 @@ Profiled, Device-dependent Colors</h2>
 	Its syntax is:
 
 	<pre class='prod'>
-		<dfn>color()</dfn> = color( [ <<ident>>? [ <<number-percentage>>+ | <<string>> ] [ / <<alpha-value>> ]? ]# , <<color>>? )
+		<dfn>color()</dfn> = color( [ [<<ident>> | <<dashed-ident>>]? [ <<number-percentage>>+ | <<string>> ] [ / <<alpha-value>> ]? ]# , <<color>>? )
 	</pre>
 
 	The color function takes one or more comma-separated arguments,
@@ -2127,13 +2130,14 @@ Profiled, Device-dependent Colors</h2>
 
 	Each argument has the following form:
 
-	* An optional <<ident>> denoting the colorspace.
-		This can be one of the predefined colorspaces
-		(such as ''display-p3''),
-		or one defined by a ''@color-profile'' rule.
+	* An optional <<ident>>  or <<dashed-ident>> denoting the colorspace.
+		If this is an <<ident>> it denotes one of the predefined colorspaces
+		(such as ''display-p3'');
+		if it is a <<dashed-ident>> it denotes a custom
+		colorspace, defined by a ''@color-profile'' rule.
 		If omitted, it defaults to the predefined ''srgb'' color profile.
 
-		If the <<ident>> names a non-existent colorspace,
+		If the <<ident>> or <<dashed-ident>> names a non-existent colorspace,
 		this argument represents an <a>invalid color</a>.
 
 	* Either one or more <<number>>s or <<percentage>>s providing the parameter values that the colorspace takes,
@@ -2425,14 +2429,15 @@ Specifying a color profile: the ''@color-profile'' at-rule</h3>
 	It's defined as:
 
 	<pre class='prod'>
-	@color-profile = @color-profile <<custom-ident>> { <<declaration-list>> }
+	@color-profile = @color-profile <<dashed-ident>> { <<declaration-list>> }
 	</pre>
 
-	The <<custom-ident>> gives the <a>color profile's</a> name.
-	All of the predefined colorspace keywords
+	The <<dashed-ident>> gives the <a>color profile's</a> name,
+	by which it will be used in a CSS stylesheet.
+	<!-- All of the predefined colorspace keywords
 	(''srgb'', ''display-p3'', ''a98-rgb'', ''prophoto-rgb'', ''rec2020'')
 	are excluded from this <<custom-ident>>,
-	as they're predefined by this specification and always available.
+	as they're predefined by this specification and always available. -->
 
 	The ''@color-profile'' rule accepts the descriptors defined in this specification.