private static Token ParseString(Reader reader, char quote)
{
Debug.Assert(reader != null);
//
// TODO Support full string syntax!
//
// string {string1}|{string2}
// string1 \"([^\n\r\f\\"]|\\{nl}|{nonascii}|{escape})*\"
// string2 \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*\'
// nonascii [^\0-\177]
// escape {unicode}|\\[^\n\r\f0-9a-f]
// unicode \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?
//
var strpos = reader.Position;
reader.MarkFromNext(); // skipping quote
char? ch;
StringBuilder sb = null;
while ((ch = reader.Read()) != quote)
{
if (ch == null)
throw new FormatException(string.Format("Unterminated string at position {0}.", strpos));
if (ch == '\\')
{
ch = reader.Read();
//
// NOTE: Only escaping of quote and backslash supported!
//
if (ch != quote && ch != '\\')
throw new FormatException(string.Format("Invalid escape sequence at position {0} in a string at position {1}.", reader.Position, strpos));
if (sb == null)
sb = new StringBuilder();
sb.Append(reader.MarkedExceptLast());
reader.Mark();
}
}
var text = reader.Marked();
if (sb != null)
text = sb.Append(text).ToString();
return Token.String(text);
}