protected Top GetTop()
{
Tokenizer.ExpectToken(Constants.Top);
Top top;
if (Tokenizer.IsNextToken(Constants.OpenBracket))
{
using (Tokenizer.ExpectBrackets())
{
var parser = new ExpressionParser(Tokenizer);
var expression = parser.Execute();
if (expression == null)
throw new SyntaxException("TOP clause requires an expression");
var brackets = new NestedExpression(null);
brackets.Expression = expression;
top = new Top(brackets);
}
}
else
{
if (Tokenizer.Current.Type != TokenType.Numeric || Tokenizer.Current.Value.Contains("."))
throw new SyntaxException(String.Format("Expected integer but found: '{0}'", Tokenizer.Current.Value));
top = new Top(new StringExpression(Tokenizer.Current.Value, null));
ReadNextToken();
}
if (Tokenizer.TokenEquals(Constants.Percent))
top.Percent = true;
return top;
}
private Expression GetNestedExpression( Expression parent )
{
Expression result;
using ( Tokenizer.ExpectBrackets() )
{
result = ReadCriteriaList( parent );
if ( Tokenizer.IsNextToken( Constants.Comma ) )
{
var list = new ExpressionList();
list.Identifiers.Add( result );
do
{
Tokenizer.ExpectToken( Constants.Comma );
result = ReadCriteriaList( parent );
list.Identifiers.Add( result );
} while ( Tokenizer.IsNextToken( Constants.Comma ) );
result = list;
}
}
NestedExpression nestedExpression = new NestedExpression( parent ) { Expression = result };
result.Parent = nestedExpression;
return nestedExpression;
}