/// <summary>
/// Tries to parse Literal Tokens into Literal Nodes.
/// </summary>
/// <param name="context">Parser Context.</param>
/// <param name="lit">Literal Token.</param>
/// <returns></returns>
private INode TryParseLiteral(TurtleParserContext context, IToken lit)
{
IToken next;
String dturi;
switch (lit.TokenType)
{
case Token.LITERAL:
case Token.LONGLITERAL:
next = context.Tokens.Peek();
if (next.TokenType == Token.LANGSPEC)
{
// Has a Language Specifier
next = context.Tokens.Dequeue();
return(context.Handler.CreateLiteralNode(lit.Value, next.Value));
}
else if (next.TokenType == Token.DATATYPE)
{
// Has a Datatype
next = context.Tokens.Dequeue();
try
{
if (next.Value.StartsWith("<"))
{
dturi = next.Value.Substring(1, next.Value.Length - 2);
return(context.Handler.CreateLiteralNode(lit.Value, UriFactory.Create(Tools.ResolveUri(dturi, context.BaseUri.ToSafeString()))));
}
else
{
dturi = Tools.ResolveQName(next.Value, context.Namespaces, context.BaseUri);
return(context.Handler.CreateLiteralNode(lit.Value, UriFactory.Create(dturi)));
}
}
catch (RdfException rdfEx)
{
throw new RdfParseException("Unable to resolve the Datatype '" + next.Value + "' due to the following error:\n" + rdfEx.Message, next, rdfEx);
}
}
else
{
// Just an untyped Literal
return(context.Handler.CreateLiteralNode(lit.Value));
}
case Token.LITERALWITHDT:
LiteralWithDataTypeToken litdt = (LiteralWithDataTypeToken)lit;
try
{
if (litdt.DataType.StartsWith("<"))
{
dturi = litdt.DataType.Substring(1, litdt.DataType.Length - 2);
return(context.Handler.CreateLiteralNode(litdt.Value, UriFactory.Create(Tools.ResolveUri(dturi, context.BaseUri.ToSafeString()))));
}
else
{
dturi = Tools.ResolveQName(litdt.DataType, context.Namespaces, context.BaseUri);
return(context.Handler.CreateLiteralNode(litdt.Value, UriFactory.Create(dturi)));
}
}
catch (RdfException rdfEx)
{
throw new RdfParseException("Unable to resolve the Datatype '" + litdt.DataType + "' due to the following error:\n" + rdfEx.Message, litdt, rdfEx);
}
case Token.LITERALWITHLANG:
LiteralWithLanguageSpecifierToken langlit = (LiteralWithLanguageSpecifierToken)lit;
return(context.Handler.CreateLiteralNode(langlit.Value, langlit.Language));
case Token.PLAINLITERAL:
// Attempt to infer Type
if (TurtleSpecsHelper.IsValidPlainLiteral(lit.Value, _syntax))
{
if (TurtleSpecsHelper.IsValidDouble(lit.Value))
{
return(context.Handler.CreateLiteralNode(lit.Value, UriFactory.Create(XmlSpecsHelper.XmlSchemaDataTypeDouble)));
}
else if (TurtleSpecsHelper.IsValidInteger(lit.Value))
{
return(context.Handler.CreateLiteralNode(lit.Value, UriFactory.Create(XmlSpecsHelper.XmlSchemaDataTypeInteger)));
}
else if (TurtleSpecsHelper.IsValidDecimal(lit.Value))
{
return(context.Handler.CreateLiteralNode(lit.Value, UriFactory.Create(XmlSpecsHelper.XmlSchemaDataTypeDecimal)));
}
else
{
return(context.Handler.CreateLiteralNode(lit.Value.ToLower(), UriFactory.Create(XmlSpecsHelper.XmlSchemaDataTypeBoolean)));
}
}
else
{
throw ParserHelper.Error("The value '" + lit.Value + "' is not valid as a Plain Literal in Turtle", lit);
}
default:
throw ParserHelper.Error("Unexpected Token '" + lit.GetType().ToString() + "' encountered, expected a valid Literal Token to convert to a Node", lit);
}
}
