/// <summary>
/// Consumes a sequence of tokens representing a UVSS selector part.
/// </summary>
/// <param name="state">The parser state.</param>
/// <param name="allowEOF">A value indicating whether hitting the end of file is valid.</param>
/// <param name="allowPseudoClass">A value indicating whether parts with pseduo classes are valid.</param>
/// <param name="allowChild">A value indicating whether this selector part can be an immediate child.</param>
/// <returns>A new <see cref="UvssSelectorPart"/> object representing the selector part that was consumed.</returns>
private static UvssSelectorPart ConsumeSelectorPart(UvssParserState state, Boolean allowEOF, Boolean allowPseudoClass, Boolean allowChild)
{
var element = default(String);
var id = default(String);
var pseudoClass = default(String);
var classes = new List<String>();
var valid = false;
var qualifier = UvssSelectorPartQualifier.None;
var universal = false;
var elementIsExact = false;
while (true)
{
if (state.IsPastEndOfStream)
{
if (allowEOF && (qualifier == UvssSelectorPartQualifier.None || valid))
{
break;
}
ThrowUnexpectedEOF(state);
}
var token = state.CurrentToken;
if (token.TokenType == UvssLexerTokenType.WhiteSpace ||
token.TokenType == UvssLexerTokenType.Comma ||
token.TokenType == UvssLexerTokenType.OpenCurlyBrace ||
token.TokenType == UvssLexerTokenType.Pipe)
{
if (qualifier != UvssSelectorPartQualifier.None && !valid)
{
ThrowUnexpectedToken(state, token);
}
break;
}
if (token.TokenType == UvssLexerTokenType.ChildSelector || token.TokenType == UvssLexerTokenType.LogicalChildSelector || token.TokenType == UvssLexerTokenType.TemplatedChildSelector)
{
if (!allowChild)
ThrowUnexpectedToken(state, token);
switch (token.TokenType)
{
case UvssLexerTokenType.ChildSelector:
qualifier = UvssSelectorPartQualifier.VisualChild;
break;
case UvssLexerTokenType.LogicalChildSelector:
qualifier = UvssSelectorPartQualifier.LogicalChild;
break;
case UvssLexerTokenType.TemplatedChildSelector:
qualifier = UvssSelectorPartQualifier.TemplatedChild;
break;
}
state.Advance();
state.AdvanceBeyondWhiteSpace();
continue;
}
if (token.TokenType == UvssLexerTokenType.Identifier || token.TokenType == UvssLexerTokenType.UniversalSelector)
{
if (!String.IsNullOrEmpty(pseudoClass))
ThrowUnexpectedToken(state, token);
state.Advance();
if (token.TokenType == UvssLexerTokenType.UniversalSelector)
{
valid = true;
universal = true;
continue;
}
else
{
var typename = default(String);
var specific = false;
if (IsSelectorForElement(token.Value, out typename, out specific))
{
if (element != null || universal)
ThrowUnexpectedValue(state, token);
valid = true;
element = typename;
elementIsExact = specific;
continue;
}
}
if (IsSelectorForID(token.Value))
{
if (id != null)
ThrowUnexpectedValue(state, token);
valid = true;
id = token.Value;
continue;
}
valid = true;
classes.Add(token.Value);
continue;
}
if (token.TokenType == UvssLexerTokenType.Colon)
{
if (!valid)
ThrowUnexpectedToken(state, token);
state.Advance();
var identifier = state.TryConsume();
if (identifier == null)
ThrowUnexpectedEOF(state);
if (identifier.Value.TokenType != UvssLexerTokenType.Identifier)
ThrowExpectedToken(state, identifier.Value, UvssLexerTokenType.Identifier);
pseudoClass = identifier.Value.Value;
break;
}
if (valid)
break;
ThrowUnexpectedToken(state, token);
}
return valid ? new UvssSelectorPart(qualifier, element, elementIsExact, id, pseudoClass, classes) : null;
}