private QueryParser(TextReader reader)
{
_scanner = new QueryScanner(reader);
_scanner.Next();
}
public IExpression ParseQuery(bool includeHintTerms)
{
if (_scanner.Current.Type == TokenType.End)
{
return(null);
}
List <IExpression> terms = new List <IExpression>();
// Parse the first term
IExpression term = ParseAndExpression(includeHintTerms);
if (term == null)
{
return(null);
}
terms.Add(term);
while (_scanner.Current.Type == TokenType.BooleanOperatorOr)
{
// If this is an 'Or', combine with the next expression
string operatorText = _scanner.Current.Content;
_scanner.Next();
if (_scanner.Current.Type == TokenType.End && String.IsNullOrEmpty(_scanner.Current.Prefix) && operatorText == "|")
{
// If '|' was typed and there's no follow space, keep suggesting '||'
if (includeHintTerms)
{
terms.Add(new TermExpression("")
{
Guidance = new IntelliSenseGuidance(operatorText, QueryTokenCategory.BooleanOperator)
});
}
}
else
{
term = ParseAndExpression(includeHintTerms);
if (term == null && includeHintTerms)
{
term = new TermExpression("")
{
Guidance = new IntelliSenseGuidance("", QueryTokenCategory.Term)
}
}
;
if (term != null)
{
terms.Add(term);
}
}
}
// If there was something invalid at the end of the query, return a null result
if (_scanner.Current.Type != TokenType.End && _scanner.Current.Type != TokenType.RightParen)
{
return(null);
}
if (terms.Count == 1)
{
return(terms[0]);
}
else
{
return(new OrExpression(terms.ToArray()));
}
}