/// <summary>
/// Try to make an Esmtp-Parameter from the tokens.
/// </summary>
/// <param name="enumerator">The enumerator to perform the make on.</param>
/// <param name="parameter">The esmtp-parameter that was made.</param>
/// <returns>true if the esmtp-parameter can be made, false if not.</returns>
/// <remarks><![CDATA[esmtp-keyword ["=" esmtp-value]]]></remarks>
public bool TryMakeEsmtpParameter(TokenEnumerator enumerator, out KeyValuePair <string, string> parameter)
{
parameter = default(KeyValuePair <string, string>);
string keyword;
if (TryMake(enumerator, TryMakeEsmtpKeyword, out keyword) == false)
{
return(false);
}
if (enumerator.Peek().Kind == TokenKind.None || enumerator.Peek().Kind == TokenKind.Space)
{
parameter = new KeyValuePair <string, string>(keyword, null);
return(true);
}
if (enumerator.Peek() != new Token(TokenKind.Symbol, "="))
{
return(false);
}
enumerator.Take();
string value;
if (TryMake(enumerator, TryMakeEsmtpValue, out value) == false)
{
return(false);
}
parameter = new KeyValuePair <string, string>(keyword, value);
return(true);
}
/// <summary>
/// Make an AUTH command from the given enumerator.
/// </summary>
/// <param name="enumerator">The enumerator to create the command from.</param>
/// <param name="command">The AUTH command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>Returns true if a command could be made, false if not.</returns>
public bool TryMakeAuth(TokenEnumerator enumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
Debug.Assert(enumerator.Peek() == new Token(TokenKind.Text, "AUTH"));
command = null;
errorResponse = null;
enumerator.Take();
enumerator.TakeWhile(TokenKind.Space);
AuthenticationMethod method;
if (Enum.TryParse(enumerator.Peek().Text, true, out method) == false)
{
_logger.LogVerbose("AUTH command requires a valid method (PLAIN or LOGIN)");
errorResponse = SmtpResponse.SyntaxError;
return(false);
}
enumerator.Take();
string parameter = null;
if (enumerator.Count > 0 && _parser.TryMakeBase64(enumerator, out parameter) == false)
{
_logger.LogVerbose("AUTH parameter must be a Base64 encoded string");
errorResponse = SmtpResponse.SyntaxError;
return(false);
}
command = new AuthCommand(_options.UserAuthenticator, method, parameter);
return(true);
}
internal bool TryMakeEsmtpKeyword(TokenEnumerator enumerator, out string keyword)
{
keyword = null;
Token left = enumerator.Peek(0);
while (left.Kind == TokenKind.Text || left.Kind == TokenKind.Number || left == new Token(TokenKind.Punctuation, "-"))
{
keyword += enumerator.Consume(1).Text;
left = enumerator.Peek(0);
}
return(keyword != null);
}
internal bool TryMakeTextOrNumberOrHyphenString(TokenEnumerator enumerator, out string textOrNumberOrHyphenString)
{
textOrNumberOrHyphenString = null;
Token left = enumerator.Peek(0);
while (left.Kind == TokenKind.Text || left.Kind == TokenKind.Number || left == new Token(TokenKind.Punctuation, "-"))
{
textOrNumberOrHyphenString += enumerator.Consume(1).Text;
left = enumerator.Peek(0);
}
return(textOrNumberOrHyphenString != null && left != new Token(TokenKind.Punctuation, "-"));
}
/// <summary>
/// Try to make an Esmtp-Keyword from the tokens.
/// </summary>
/// <param name="enumerator">The enumerator to perform the make on.</param>
/// <param name="keyword">The esmtp-keyword that was made.</param>
/// <returns>true if the esmtp-keyword can be made, false if not.</returns>
/// <remarks><![CDATA[(ALPHA / DIGIT) *(ALPHA / DIGIT / "-")]]></remarks>
public bool TryMakeEsmtpKeyword(TokenEnumerator enumerator, out string keyword)
{
keyword = null;
var token = enumerator.Peek();
while (token.Kind == TokenKind.Text || token.Kind == TokenKind.Number || token == new Token(TokenKind.Punctuation, "-"))
{
keyword += enumerator.Take().Text;
token = enumerator.Peek();
}
return(keyword != null);
}
/// <summary>
/// Try to make an Esmtp-Value from the tokens.
/// </summary>
/// <param name="enumerator">The enumerator to perform the make on.</param>
/// <param name="value">The esmtp-value that was made.</param>
/// <returns>true if the esmtp-value can be made, false if not.</returns>
/// <remarks><![CDATA[1*(%d33-60 / %d62-127)]]></remarks>
public bool TryMakeEsmtpValue(TokenEnumerator enumerator, out string value)
{
value = null;
var token = enumerator.Peek();
while (token.Text.Length > 0 && token.Text.ToCharArray().All(ch => (ch >= 33 && ch <= 66) || (ch >= 62 && ch <= 127)))
{
value += enumerator.Take().Text;
token = enumerator.Peek();
}
return(value != null);
}
/// <summary>
/// Make an EHLO command from the given enumerator.
/// </summary>
/// <param name="enumerator">The enumerator to create the command from.</param>
/// <param name="command">The EHLO command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>Returns true if a command could be made, false if not.</returns>
public bool TryMakeEhlo(TokenEnumerator enumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
Debug.Assert(enumerator.Peek() == new Token(TokenKind.Text, "EHLO"));
command = null;
errorResponse = null;
enumerator.Take();
enumerator.TakeWhile(TokenKind.Space);
string domain;
if (_parser.TryMakeDomain(enumerator, out domain))
{
command = new EhloCommand(domain, _options);
return(true);
}
string address;
if (_parser.TryMakeAddressLiteral(enumerator, out address))
{
command = new EhloCommand(address, _options);
return(true);
}
errorResponse = SmtpResponse.SyntaxError;
return(false);
}
internal bool TryMakeEsmtpValue(TokenEnumerator enumerator, out string value)
{
value = null;
Token token = enumerator.Peek(0);
while (token.Text.Length > 0)
{
if (!token.Text.ToCharArray().All((char ch) => (ch >= '!' && ch <= 'B') || (ch >= '>' && ch <= '\u007f')))
{
break;
}
value += enumerator.Consume(1).Text;
token = enumerator.Peek(0);
}
return(value != null);
}
/// <summary>
/// Make a RCTP command from the given enumerator.
/// </summary>
/// <param name="enumerator">The enumerator to create the command from.</param>
/// <param name="command">The RCTP command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>Returns true if a command could be made, false if not.</returns>
public bool TryMakeRcpt(TokenEnumerator enumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
Debug.Assert(enumerator.Peek() == new Token(TokenKind.Text, "RCPT"));
command = null;
errorResponse = null;
enumerator.Take();
enumerator.TakeWhile(TokenKind.Space);
if (enumerator.Take() != new Token(TokenKind.Text, "TO") || enumerator.Take() != new Token(TokenKind.Punctuation, ":"))
{
errorResponse = new SmtpResponse(SmtpReplyCode.SyntaxError, "missing the TO:");
return(false);
}
// according to the spec, whitespace isnt allowed here anyway
enumerator.TakeWhile(TokenKind.Space);
IMailbox mailbox;
if (_parser.TryMakePath(enumerator, out mailbox) == false)
{
_logger.LogVerbose("Syntax Error (Text={0})", enumerator.AsText());
errorResponse = SmtpResponse.SyntaxError;
return(false);
}
// TODO: support optional service extension parameters here
command = new RcptCommand(mailbox, _options.MailboxFilterFactory);
return(true);
}
/// <summary>
/// Try to make a text/number/hyphen string.
/// </summary>
/// <param name="enumerator">The enumerator to make the text/number/hyphen from.</param>
/// <param name="textOrNumberOrHyphenString">The text, number, or hyphen that was matched, or undefined if it was not matched.</param>
/// <returns>true if a text, number or hyphen was made, false if not.</returns>
/// <remarks><![CDATA[*( ALPHA / DIGIT / "-" ) Let-dig]]></remarks>
public bool TryMakeTextOrNumberOrHyphenString(TokenEnumerator enumerator, out string textOrNumberOrHyphenString)
{
textOrNumberOrHyphenString = null;
var token = enumerator.Peek();
while (token.Kind == TokenKind.Text || token.Kind == TokenKind.Number || token == new Token(TokenKind.Punctuation, "-"))
{
textOrNumberOrHyphenString += enumerator.Take().Text;
token = enumerator.Peek();
}
// can not end with a hyphen
return(textOrNumberOrHyphenString != null && token != new Token(TokenKind.Punctuation, "-"));
}
/// <summary>
/// Try to make an IPv4 address literal.
/// </summary>
/// <param name="enumerator">The enumerator to make the address from.</param>
/// <param name="address">The address that was made, or undefined if it was not made.</param>
/// <returns>true if the address was made, false if not.</returns>
/// <remarks><![CDATA[ Snum 3("." Snum) ]]></remarks>
public bool TryMakeIpv4AddressLiteral(TokenEnumerator enumerator, out string address)
{
address = null;
int snum;
if (TryMake(enumerator, TryMakeSnum, out snum) == false)
{
return(false);
}
address = snum.ToString(CultureInfo.InvariantCulture);
for (var i = 0; i < 3 && enumerator.Peek() == new Token(TokenKind.Punctuation, "."); i++)
{
enumerator.Take();
if (TryMake(enumerator, TryMakeSnum, out snum) == false)
{
return(false);
}
address = String.Concat(address, '.', snum);
}
return(true);
}
public void EnumerateTokens()
{
var tokenizer = new TokenEnumerator(new ByteArrayTokenReader(Segments));
while (tokenizer.Peek() != Token.None)
{
tokenizer.Take();
}
}
internal bool TryMakeBase64(TokenEnumerator enumerator, out string base64)
{
base64 = null;
while (enumerator.Peek(0).Kind != TokenKind.None)
{
string str;
if (!TryMake <string>(enumerator, new TryMakeDelegate <string>(TryMakeBase64Chars), out str))
{
return(false);
}
base64 += str;
}
return(base64 != null && base64.Length % 4 == 0);
}
internal bool TryMakeMailParameters(TokenEnumerator enumerator, out IDictionary <string, string> parameters)
{
parameters = new Dictionary <string, string>(StringComparer.OrdinalIgnoreCase);
while (enumerator.Peek(0).Kind != TokenKind.None)
{
KeyValuePair <string, string> item;
if (!TryMake <KeyValuePair <string, string> >(enumerator, new TryMakeDelegate <KeyValuePair <string, string> >(TryMakeEsmtpParameter), out item))
{
return(false);
}
parameters.Add(item);
enumerator.ConsumeWhile((Token t) => t.Kind == TokenKind.Space);
}
return(parameters.Count > 0);
}
internal bool TryMakeAtDomainList(TokenEnumerator enumerator, out string atDomainList)
{
if (!TryMake <string>(enumerator, new TryMakeDelegate <string>(TryMakeAtDomain), out atDomainList))
{
return(false);
}
while (enumerator.Peek(0) == new Token(TokenKind.Punctuation, ","))
{
enumerator.Consume(1);
string arg;
if (!TryMake <string>(enumerator, new TryMakeDelegate <string>(TryMakeAtDomain), out arg))
{
return(false);
}
atDomainList += string.Format(",{0}", arg);
}
return(true);
}
internal bool TryMakeDotString(TokenEnumerator enumerator, out string dotString)
{
if (!TryMake <string>(enumerator, new TryMakeDelegate <string>(TryMakeAtom), out dotString))
{
return(false);
}
while (enumerator.Peek(0) == new Token(TokenKind.Punctuation, "."))
{
enumerator.Consume(1);
string str;
if (!TryMake <string>(enumerator, new TryMakeDelegate <string>(TryMakeAtom), out str))
{
return(true);
}
dotString += "." + str;
}
return(true);
}
internal bool TryAccept(TokenEnumerator tokenEnumerator, out SmtpCommand command)
{
Tuple <State.MakeDelegate, int> tuple;
if (!_state.Actions.TryGetValue(tokenEnumerator.Peek(0).Text, out tuple))
{
string response = string.Format("expected {0}", string.Join("/", _state.Actions.Keys));
command = _commandFactory.MakeInvalid(SmtpReplyCode.SyntaxError, response);
return(false);
}
command = tuple.Item1(tokenEnumerator);
if (!(command is InvalidCommand))
{
_state = _states[tuple.Item2];
return(true);
}
return(false);
}
/// <summary>
/// Try to make an Mail-Parameters from the tokens.
/// </summary>
/// <param name="enumerator">The enumerator to perform the make on.</param>
/// <param name="parameters">The mail parameters that were made.</param>
/// <returns>true if the mail parameters can be made, false if not.</returns>
/// <remarks><![CDATA[esmtp-param *(SP esmtp-param)]]></remarks>
public bool TryMakeMailParameters(TokenEnumerator enumerator, out IDictionary <string, string> parameters)
{
parameters = new Dictionary <string, string>(StringComparer.OrdinalIgnoreCase);
while (enumerator.Peek().Kind != TokenKind.None)
{
KeyValuePair <string, string> parameter;
if (TryMake(enumerator, TryMakeEsmtpParameter, out parameter) == false)
{
return(false);
}
parameters.Add(parameter);
enumerator.TakeWhile(t => t.Kind == TokenKind.Space);
}
return(parameters.Count > 0);
}
internal SmtpCommand MakeAuth(TokenEnumerator enumerator)
{
enumerator.Consume(1);
enumerator.ConsumeWhile((Token t) => t.Kind == TokenKind.Space);
AuthenticationMethod method;
if (!Enum.TryParse(enumerator.Peek(0).Text, true, out method))
{
return(MakeInvalid(SmtpReplyCode.SyntaxError, ""));
}
enumerator.Consume(1);
string parameter = null;
if (enumerator.Count > 0 && !_parser.TryMakeBase64(enumerator, out parameter))
{
return(MakeInvalid(SmtpReplyCode.SyntaxError, ""));
}
return(new AuthCommand(_server.UserAuthenticator, method, parameter));
}
/// <summary>
/// Try to make a base64 encoded string.
/// </summary>
/// <param name="enumerator">The enumerator to perform the make on.</param>
/// <param name="base64">The base64 encoded string that were found.</param>
/// <returns>true if the base64 encoded string can be made, false if not.</returns>
/// <remarks><![CDATA[ALPHA / DIGIT / "+" / "/"]]></remarks>
public bool TryMakeBase64(TokenEnumerator enumerator, out string base64)
{
base64 = null;
while (enumerator.Peek().Kind != TokenKind.None)
{
string base64Chars;
if (TryMake(enumerator, TryMakeBase64Chars, out base64Chars) == false)
{
return(false);
}
base64 += base64Chars;
}
// because the TryMakeBase64Chars method matches tokens, each Text token could make
// up several Base64 encoded "bytes" so we ensure that we have a length divisible by 4
return(base64 != null && base64.Length % 4 == 0);
}
/// <summary>
/// Advances the enumerator to the next command in the stream.
/// </summary>
/// <param name="context">The session context to use for making session based transitions.</param>
/// <param name="tokenEnumerator">The token enumerator to accept the command from.</param>
/// <param name="command">The command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>true if a valid command was found, false if not.</returns>
public bool TryMake(SmtpSessionContext context, TokenEnumerator tokenEnumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
if (_states[_current].Transitions.TryGetValue(tokenEnumerator.Peek().Text, out _transition) == false)
{
var response = $"expected {String.Join("/", _states[_current].Transitions.Keys)}";
command = null;
errorResponse = new SmtpResponse(SmtpReplyCode.SyntaxError, response);
return(false);
}
if (_transition.Delegate(tokenEnumerator, out command, out errorResponse) == false)
{
return(false);
}
return(true);
}
/// <summary>
/// Make a MAIL command from the given enumerator.
/// </summary>
/// <param name="enumerator">The enumerator to create the command from.</param>
/// <param name="command">The MAIL command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>Returns true if a command could be made, false if not.</returns>
public bool TryMakeMail(TokenEnumerator enumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
Debug.Assert(enumerator.Peek() == new Token(TokenKind.Text, "MAIL"));
command = null;
errorResponse = null;
enumerator.Take();
enumerator.TakeWhile(TokenKind.Space);
if (enumerator.Take() != new Token(TokenKind.Text, "FROM") || enumerator.Take() != new Token(TokenKind.Punctuation, ":"))
{
errorResponse = new SmtpResponse(SmtpReplyCode.SyntaxError, "missing the FROM:");
return(false);
}
// according to the spec, whitespace isnt allowed here but most servers send it
enumerator.TakeWhile(TokenKind.Space);
IMailbox mailbox;
if (_parser.TryMakeReversePath(enumerator, out mailbox) == false)
{
_logger.LogVerbose("Syntax Error (Text={0})", enumerator.AsText());
errorResponse = new SmtpResponse(SmtpReplyCode.SyntaxError);
return(false);
}
enumerator.TakeWhile(TokenKind.Space);
// match the optional (ESMTP) parameters
IReadOnlyDictionary <string, string> parameters;
if (_parser.TryMakeMailParameters(enumerator, out parameters) == false)
{
parameters = new Dictionary <string, string>();
}
command = new MailCommand(_options, mailbox, parameters);
return(true);
}
/// <summary>
/// Make an RSET command from the given enumerator.
/// </summary>
/// <param name="enumerator">The enumerator to create the command from.</param>
/// <param name="command">The RSET command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>Returns true if a command could be made, false if not.</returns>
public bool TryMakeRset(TokenEnumerator enumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
Debug.Assert(enumerator.Peek() == new Token(TokenKind.Text, "RSET"));
command = null;
errorResponse = null;
enumerator.Take();
enumerator.TakeWhile(TokenKind.Space);
if (enumerator.Count > 1)
{
_logger.LogVerbose("RSET command can not have parameters (found {0} parameters).", enumerator.Count);
errorResponse = SmtpResponse.SyntaxError;
return(false);
}
command = RsetCommand.Instance;
return(true);
}
/// <summary>
/// Make an STARTTLS command from the given enumerator.
/// </summary>
/// <param name="enumerator">The enumerator to create the command from.</param>
/// <param name="command">The STARTTLS command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>Returns true if a command could be made, false if not.</returns>
public bool TryMakeStartTls(TokenEnumerator enumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
Debug.Assert(enumerator.Peek() == new Token(TokenKind.Text, "STARTTLS"));
command = null;
errorResponse = null;
enumerator.Take();
enumerator.TakeWhile(TokenKind.Space);
if (enumerator.Count > 1)
{
_logger.LogVerbose("STARTTLS command can not have parameters (Tokens={0})", enumerator.Count);
errorResponse = SmtpResponse.SyntaxError;
return(false);
}
command = new StartTlsCommand(_options.ServerCertificate);
return(true);
}
/// <summary>
/// Make a DATA command from the given enumerator.
/// </summary>
/// <param name="enumerator">The enumerator to create the command from.</param>
/// <param name="command">The DATA command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>Returns true if a command could be made, false if not.</returns>
public bool TryMakeData(TokenEnumerator enumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
Debug.Assert(enumerator.Peek() == new Token(TokenKind.Text, "DATA"));
command = null;
errorResponse = null;
enumerator.Take();
enumerator.TakeWhile(TokenKind.Space);
if (enumerator.Count > 1)
{
_logger.LogVerbose("DATA command can not have parameters (Tokens={0})", enumerator.Count);
errorResponse = SmtpResponse.SyntaxError;
return(false);
}
command = new DataCommand(_options.MessageStoreFactory);
return(true);
}
/// <summary>
/// Try to make a quoted-string from the tokens.
/// </summary>
/// <param name="enumerator">The enumerator to make the quoted-string from.</param>
/// <param name="quotedString">The quoted-string that was made, or undefined if it was not made.</param>
/// <returns>true if the quoted-string was made, false if not.</returns>
/// <remarks><![CDATA[DQUOTE * QcontentSMTP DQUOTE]]></remarks>
public bool TryMakeQuotedString(TokenEnumerator enumerator, out string quotedString)
{
quotedString = null;
if (enumerator.Take() != new Token(TokenKind.Punctuation, "\""))
{
return(false);
}
while (enumerator.Peek() != new Token(TokenKind.Punctuation, "\""))
{
string text;
if (TryMakeQContentSmtp(enumerator, out text) == false)
{
return(false);
}
quotedString += text;
}
return(enumerator.Take() == new Token(TokenKind.Punctuation, "\""));
}
/// <summary>
/// Try to make a domain name.
/// </summary>
/// <param name="enumerator">The enumerator to make the domain name from.</param>
/// <param name="domain">The domain name that was made, or undefined if it was not made.</param>
/// <returns>true if the domain name was made, false if not.</returns>
/// <remarks><![CDATA[sub-domain *("." sub-domain)]]></remarks>
public bool TryMakeDomain(TokenEnumerator enumerator, out string domain)
{
if (TryMake(enumerator, TryMakeSubdomain, out domain) == false)
{
return(false);
}
while (enumerator.Peek() == new Token(TokenKind.Punctuation, "."))
{
enumerator.Take();
string subdomain;
if (TryMake(enumerator, TryMakeSubdomain, out subdomain) == false)
{
return(false);
}
domain += String.Concat(".", subdomain);
}
return(true);
}
/// <summary>
/// Make a HELO command from the given enumerator.
/// </summary>
/// <param name="enumerator">The enumerator to create the command from.</param>
/// <param name="command">The HELO command that is defined within the token enumerator.</param>
/// <param name="errorResponse">The error that indicates why the command could not be made.</param>
/// <returns>Returns true if a command could be made, false if not.</returns>
public bool TryMakeHelo(TokenEnumerator enumerator, out SmtpCommand command, out SmtpResponse errorResponse)
{
Debug.Assert(enumerator.Peek() == new Token(TokenKind.Text, "HELO"));
command = null;
errorResponse = null;
enumerator.Take();
enumerator.TakeWhile(TokenKind.Space);
string domain;
if (_parser.TryMakeDomain(enumerator, out domain) == false)
{
_logger.LogVerbose("Could not match the domain name (Text={0}).", enumerator.AsText());
errorResponse = SmtpResponse.SyntaxError;
return(false);
}
command = new HeloCommand(domain);
return(true);
}
/// <summary>
/// Try to make an @domain list.
/// </summary>
/// <param name="enumerator">The enumerator to make the @domain list from.</param>
/// <param name="atDomainList">The @domain list that was made, or undefined if it was not made.</param>
/// <returns>true if the @domain list was made, false if not.</returns>
/// <remarks><![CDATA[At-domain *( "," At-domain )]]></remarks>
public bool TryMakeAtDomainList(TokenEnumerator enumerator, out string atDomainList)
{
if (TryMake(enumerator, TryMakeAtDomain, out atDomainList) == false)
{
return(false);
}
// match the optional list
while (enumerator.Peek() == new Token(TokenKind.Punctuation, ","))
{
enumerator.Take();
string atDomain;
if (TryMake(enumerator, TryMakeAtDomain, out atDomain) == false)
{
return(false);
}
atDomainList += String.Format(",{0}", atDomain);
}
return(true);
}
/// <summary>
/// Try to make a dot-string from the tokens.
/// </summary>
/// <param name="enumerator">The enumerator to make the dot-string from.</param>
/// <param name="dotString">The dot-string that was made, or undefined if it was not made.</param>
/// <returns>true if the dot-string was made, false if not.</returns>
/// <remarks><![CDATA[Atom *("." Atom)]]></remarks>
public bool TryMakeDotString(TokenEnumerator enumerator, out string dotString)
{
if (TryMake(enumerator, TryMakeAtom, out dotString) == false)
{
return(false);
}
while (enumerator.Peek() == new Token(TokenKind.Punctuation, "."))
{
// skip the punctuation
enumerator.Take();
string atom;
if (TryMake(enumerator, TryMakeAtom, out atom) == false)
{
return(true);
}
dotString += String.Concat(".", atom);
}
return(true);
}