private static int GetNCharOperatorLength(CharacterStream cs) {
// R allows user-defined infix operators. These have the form of
// a string of characters delimited by the ‘%’ character. The string
// can contain any printable character except ‘%’.
if (cs.CurrentChar == '%' && !char.IsWhiteSpace(cs.NextChar)) {
// In case of broken or partially typed operators
// make sure we terminate at whitespace or end of the line
// so in 'x <- y % z' '% z' is not an operator.
int start = cs.Position;
int length;
cs.MoveToNextChar();
while (!cs.IsEndOfStream() && !cs.IsWhiteSpace()) {
if (cs.CurrentChar == '%') {
cs.MoveToNextChar();
length = cs.Position - start;
cs.Position = start;
return length;
}
if (cs.IsAtNewLine()) {
// x <- y %abcd
cs.Position = start;
return 1;
}
cs.MoveToNextChar();
}
}
return Get3CharOrShorterOperatorLength(cs);
}
/// <summary>
/// Handle generic comment. Comment goes to the end of the line.
/// </summary>
public static void HandleEolComment(CharacterStream cs, Action<int, int> addToken) {
int start = cs.Position;
while (!cs.IsEndOfStream() && !cs.IsAtNewLine()) {
cs.MoveToNextChar();
}
int length = cs.Position - start;
if (length > 0) {
addToken(start, length);
}
}