private ParseNode ParseTextOptional(TokenStream tokenStream, ref ParserState state)
{
if (tokenStream.Current.Symbol != TexSymbolKind.Text)
{
return(null);
}
tokenStream.ForceMoveNext();
switch (tokenStream.Current.Symbol)
{
case TexSymbolKind.GroupOpen:
tokenStream.ForceMoveNext();
var sb = new StringBuilder();
while (tokenStream.Current.Symbol != TexSymbolKind.GroupClose)
{
sb.Append((char)tokenStream.Current.Value);
tokenStream.ForceMoveNext();
}
if (sb.Length == 0)
{
throw new TexParserException(tokenStream.Current, errorMessageTextValueEmpty);
}
tokenStream.ForceMoveNext();
return(new ParseNode(TexToken.FromValue(TexSymbolKind.Text, sb.ToString(),
tokenStream.Current.SourcePosition, null)));
default:
throw new TexParserException(tokenStream.Current, new[] {
TexSymbolKind.GroupOpen
});
}
}
public TokenStream Tokenise(TrackedTextReader reader)
{
char nextChar;
while (reader.Peek() != -1)
{
nextChar = (char)reader.Peek();
if (char.IsWhiteSpace(nextChar))
{
reader.Read();
}
else if (char.IsDigit(nextChar))
{
yield return(TexToken.FromNumber(ScanReal(reader), reader.Position, nextChar.ToString()));
}
else if (nextChar == '\\')
{
object value;
var token = TexToken.FromValue(ScanLongSymbol(reader, out value), value, reader.Position,
nextChar.ToString());
if (token.Symbol != TexSymbolKind.Unknown)
{
yield return(token);
}
}
else
{
object value;
yield return(TexToken.FromValue(ScanShortSymbol(reader, out value), value, reader.Position,
nextChar.ToString()));
}
}
yield return(TexToken.FromSymbol(TexSymbolKind.EndOfStream, reader.Position, null));
}
private void WriteValueNode(ComposedTokenStream tokenStream, TexExpressionNode node,
ComposerState state)
{
tokenStream.Write(TexToken.FromValue(node.Symbol, node.Value));
}