public override object VisitExprSign([NotNull] MiniSQLParser.ExprSignContext context)
{
Expression left = (Expression)Visit(context.expr());
// optimize expression
if (context.PLUS_OPERATOR() != null)
{
if (left.ConcreteValue.Type == AttributeTypes.Char)
{
throw new System.InvalidOperationException("Operator '+' cannot be applied to operand of type 'string'");
}
return(left);
}
// if (left.Operator == Operator.AtomConcreteValue)
// {
// if (left.ConcreteValue.Type == AttributeType.Char)
// throw new System.InvalidOperationException("Operator '-' cannot be applied to operand of type 'string'");
// if (left.ConcreteValue.Type == AttributeType.Int)
// left.ConcreteValue.IntegerValue = -left.ConcreteValue.IntegerValue;
// if (left.ConcreteValue.Type == AttributeType.Float)
// left.ConcreteValue.FloatValue = -left.ConcreteValue.FloatValue;
// return left;
// }
Expression obj = new Expression();
obj.LeftOperand = left;
obj.Operator = Operator.Negative;
// optimize expression
if (left.Operator == Operator.AtomConcreteValue)
{
left.ConcreteValue = obj.Calculate(null);
return(left);
}
return(obj);
}
/// <summary>
/// Exit a parse tree produced by the <c>exprSign</c>
/// labeled alternative in <see cref="MiniSQLParser.expr"/>.
/// <para>The default implementation does nothing.</para>
/// </summary>
/// <param name="context">The parse tree.</param>
public virtual void ExitExprSign([NotNull] MiniSQLParser.ExprSignContext context)
{
}
/// <summary>
/// Visit a parse tree produced by the <c>exprSign</c>
/// labeled alternative in <see cref="MiniSQLParser.expr"/>.
/// <para>
/// The default implementation returns the result of calling <see cref="AbstractParseTreeVisitor{Result}.VisitChildren(IRuleNode)"/>
/// on <paramref name="context"/>.
/// </para>
/// </summary>
/// <param name="context">The parse tree.</param>
/// <return>The visitor result.</return>
public virtual Result VisitExprSign([NotNull] MiniSQLParser.ExprSignContext context)
{
return(VisitChildren(context));
}
