/// <summary> a scanner with a CharPattern for sql server string literal.
/// a sql server string literal is a string quoted by single quote,
/// a single quote character is escaped by 2 single quotes.
/// </summary>
/// <returns> the scanner.
/// </returns>
public static Scanner IsSqlString()
{
/*
* final CharPattern open = Patterns.IsChar('\'').Seq(
* Patterns.or(Patterns.NotChar('\''), Patterns.IsString("''"))
* .Many()
* );
* return isPattern(open, "'").Seq(name, isChar('\''));
*/
Scanner q = IsChar('\'');
Scanner qs = IsPattern("sql string quoted", Patterns.Regex("(('')|[^'])*"), "quoted string");
return(qs.Between(q, q).Rename("sql string"));
}