[css3-syntax] Fix the diagrams (source only) to match normative text.

* Disallow \ in unquoted URLs
* Explicitly allow escaped newlines but not unescaped newlines in quoted strings
* Allow escape in HASH
* Define escape

This only changes Diagrams.src.html, not the spec.

Author: SimonSapin

css3-syntax/Diagrams.src.html

@@ -35,6 +35,13 @@ <h2 id=markup>Markup</h2>
 	preview.appendChild(document.createTextNode('\n\n\t'));
 }
 
+add('escape', Diagram(
+	'\\', Choice(0,
+		NonTerminal('not NL or hex digit'),
+		Sequence(
+			OneOrMore(NonTerminal('hex digit'), Comment('1-6 times')),
+			Optional(NonTerminal('WS'))))));
+
 add('IDENT', Diagram(
 	Choice(0, Skip(), '-'),
 	Choice(0, NonTerminal('a-z A-Z _ or non-ASCII'), NonTerminal('escape')),
@@ -48,23 +55,27 @@ <h2 id=markup>Markup</h2>
 	'@', NonTerminal('IDENT')));
 
 add('HASH', Diagram(
-	'#', OneOrMore(NonTerminal('a-z A-Z 0-9 _ - or non-ASCII'))));
+	'#', OneOrMore(Choice(0,
+		NonTerminal('a-z A-Z 0-9 _ - or non-ASCII'),
+		NonTerminal('escape')))));
 
 add('STRING', Diagram(
 	Choice(0,
 		Sequence(
 			'"',
 			ZeroOrMore(
 				Choice(0,
-					NonTerminal('not " or \\'),
-					NonTerminal('escape'))),
+					NonTerminal('not " \\ or NL'),
+					NonTerminal('escape'),
+					Sequence('\\', NonTerminal('NL')))),
 			'"'),
 		Sequence(
 			'\'',
 			ZeroOrMore(
 				Choice(0,
-					NonTerminal("not \' or \\"),
-					NonTerminal('escape'))),
+					NonTerminal("not ' \\ or NL"),
+					NonTerminal('escape'),
+					Sequence('\\', NonTerminal('NL')))),
 			'\''))));
 
 add('URL', Diagram(
@@ -82,7 +93,7 @@ <h2 id=markup>Markup</h2>
 			Optional(NonTerminal('WS')),
 			OneOrMore(
 				Choice(0,
-					NonTerminal('not " \' ( ) WS or NPC'),
+					NonTerminal('not " \' ( ) \\ WS or NPC'),
 					NonTerminal('escape'))),
 			Optional(NonTerminal('WS')))),
 	')'));