// Pratt Parser (http://journal.stuffwithstuff.com/2011/03/19/pratt-parsers-expression-parsing-made-easy/)
/// <summary>
/// Parses a token stream stored in Stream
/// </summary>
/// <param name="precedence">
/// Precedence level to start at. Used only as
/// inner part of the algorithm.
/// </param>
/// <returns>Resulting node in tree</returns>
public NodeBase Parse(Precedence precedence = 0)
{
Logger.Log(LogLevel.Debug, Logger.PARSER,
"Beginning parse for precedence " + precedence.ToString());
Token token = Consume();
IPrefixParselet prefix = GetPrefix(token.Type);
if (prefix == null)
{
Logger.Log(LogLevel.Error, Logger.PARSER,
"Parse failed on token " + token.ToString());
throw new MismatchedRuleException("Could not parse: " + token.ToString());
}
NodeBase left = prefix.Parse(this, token);
Logger.Log(LogLevel.Debug, Logger.PARSER, "Parse created " +
left.GetType().Name + " from initial token " + token.ToString());
while (precedence < GetPrecedence())
{
token = Consume();
IInfixParselet infix = GetInfix(token.Type);
left = infix.Parse(this, left, token);
}
return(left);
}
/// <summary>
/// Gets the current precedence in the parser's current state
/// </summary>
/// <returns>The precendence level being parsed</returns>
public Precedence GetPrecedence()
{
Token ahead = LookAhead();
if (ahead == null)
{
return(0);
}
IInfixParselet parselet = GetInfix(ahead.Type);
if (parselet != null)
{
return(parselet.PrecedenceLevel);
}
return(0);
}
protected void RegisterParselet(string tokenType, IInfixParselet parselet)
{
_infixParselets.Add(tokenType, parselet);
}
static void RegisterInfix(LoonyTokenType type, IInfixParselet parselet)
{
_infixParselets.Add(type, parselet);
}
private void Register(TokenType token, IInfixParselet parselet)
{
infixParselets.Add(token, parselet);
}
public void Register(TokenType token, IInfixParselet parselet)
{
_infixParselets.Add(token, parselet);
}
static void RegisterInfix(LoonyTokenType type, IInfixParselet parselet)
{
_infixParselets.Add(type, parselet);
}
private void RegisterInfix(TokenType type, IInfixParselet handler)
{
infixParselets.Add(type, handler);
}
public void AddInfix(TokenType tokenType, IInfixParselet parselet)
{
_infixParselets.Add(tokenType, parselet);
}
public void Register(TokenType token, IInfixParselet parselet)
{
_infixParselets.Add(token, parselet);
}
protected void RegisterParselet(string tokenType, IInfixParselet parselet)
{
_infixParselets.Add(tokenType, parselet);
}
public bool TryGetInfixParselet(out IInfixParselet parselet, TextSpan token)
{
return(_infixParselets.TryGetValue(token.Type, out parselet));
}
protected void Register(SqlToken tokenType, IInfixParselet parselet)
{
Register(tokenType.ToString(), parselet);
}
/// <summary>
/// Registers a token type to an infix parselet
/// </summary>
/// <param name="token">Token type to register</param>
/// <param name="parselet">Parselet to register to</param>
public static void RegisterInfix(TokenType token, IInfixParselet parselet)
{
Logger.Log(LogLevel.Debug, Logger.REGISTRY,
"Registering infix/postfix operator parselet for token " + token.ToString());
InfixParselets.Add(token, parselet);
}
protected void RegisterInfix(TokenType type, IInfixParselet parselet)
{
_infixParselets.Add(type, parselet);
}
