private static bool TryParseSimpleSelector(CssStringStreamReader reader, out CssSimpleSelector selector)
{
selector = null;
reader.SkipWhitespaceAndComments();
switch (reader.CurrentChar)
{
case '#':
reader.Advance();
return
(reader.TryReadIdentifier(out var id) &&
TryParseSimpleSelector(reader, CssSimpleSelectorType.IdSelector, new CssQualifiedName(id), out selector));
case '.':
reader.Advance();
return
(reader.TryReadIdentifier(out var className) &&
TryParseSimpleSelector(reader, CssSimpleSelectorType.ClassSelector, new CssQualifiedName(className), out selector));
case '*':
reader.Advance();
return(TryParseUniversalSelector(reader, out selector));
case '[':
case ':':
return(TryParseUniversalSelector(reader, out selector));
default:
return
(reader.TryReadQualifiedName(out var typeName) &&
TryParseSimpleSelector(reader, CssSimpleSelectorType.TypeSelector, typeName, out selector));
}
}
public virtual void VisitSimpleSelector(CssSimpleSelector selector)
{
switch (selector?.SimpleSelectorType)
{
case CssSimpleSelectorType.TypeSelector:
VisitTypeSelector(selector);
break;
case CssSimpleSelectorType.UniversalSelector:
VisitUniversalSelector(selector);
break;
case CssSimpleSelectorType.ClassSelector:
VisitClassSelector(selector);
break;
case CssSimpleSelectorType.IdSelector:
VisitIdSelector(selector);
break;
case null:
DefaultVisit(null);
break;
default:
throw new ArgumentOutOfRangeException(nameof(selector), $"Unknown simple selector type '{selector.SimpleSelectorType}'");
}
DefaultVisitList(selector?.AttributeSelectors);
}
private static bool TryParseSimpleSelector(CssStringStreamReader reader, CssSimpleSelectorType simpleSelectorType, CssQualifiedName name, out CssSimpleSelector selector)
{
var attributeSelectors = ParseAttributeSelectors(reader);
var pseudoClasses = ParsePseudoClasses(reader);
if (attributeSelectors == null || pseudoClasses == null)
{
selector = null;
return(false);
}
selector = new CssSimpleSelector(simpleSelectorType, name, attributeSelectors, pseudoClasses);
return(true);
}
private static bool TryParseUniversalSelector(CssStringStreamReader reader, out CssSimpleSelector selector)
=> TryParseSimpleSelector(reader, CssSimpleSelectorType.UniversalSelector, new CssQualifiedName("*"), out selector);
public virtual void VisitUniversalSelector(CssSimpleSelector selector) => DefaultVisit(selector);
public virtual void VisitTypeSelector(CssSimpleSelector selector) => DefaultVisit(selector);