public bool Parse(TextReader sourceReader)
{
Debug.Assert(sourceReader != null);
m_parser = ParserFactory.CreateParser(sourceReader);
m_parser.TrimReductions = true;
while (true)
{
switch (m_parser.Parse())
{
case ParseMessage.LexicalError:
ErrorString = string.Format("Lexical Error. Line {0}. Token {1} was not expected.", m_parser.LineNumber, m_parser.TokenText);
return(false);
case ParseMessage.SyntaxError:
StringBuilder text = new StringBuilder();
foreach (Symbol tokenSymbol in m_parser.GetExpectedTokens())
{
text.AppendFormat(" {0}", tokenSymbol);
}
ErrorString = string.Format("Syntax Error. Line {0}. Expecting: {1}.", m_parser.LineNumber, text);
return(false);
case ParseMessage.Reduction:
NonTerminalNode nonTerminal = SyntaxRuleFactory.CreateNode(m_parser.ReductionRule);
m_parser.TokenSyntaxNode = nonTerminal;
for (int i = 0; i < m_parser.ReductionCount; i++)
{
nonTerminal.AppendChildNode(m_parser.GetReductionSyntaxNode(i) as SyntaxNode);
}
// post parsing syntax check (used to segregate the difference between HAVING and WHERE
// expressions in terms of the validtity of aggregate expressions)
nonTerminal.CheckSyntax();
break;
case ParseMessage.TokenRead:
m_parser.TokenSyntaxNode = new TerminalNode(m_parser);
break;
case ParseMessage.Accept:
SyntaxTree = m_parser.TokenSyntaxNode as NonTerminalNode;
ErrorString = null;
return(true);
case ParseMessage.InternalError:
ErrorString = "Internal Error. Something is horribly wrong.";
return(false);
case ParseMessage.NotLoadedError:
ErrorString = "Grammar Table is not loaded.";
return(false);
case ParseMessage.CommentError:
ErrorString = "Comment Error. Unexpected end of input.";
return(false);
case ParseMessage.CommentBlockRead:
case ParseMessage.CommentLineRead:
// don't do anything
break;
}
}
}
