public override Table VisitOrder_item(QueryParser.Order_itemContext context)
{
int Comparer(TableRow row1, TableRow row2)
{
var env1 = new Environment(row1, _table.Columns);
var expr1 = new CondExprVisitor(_zmi, env1).Visit(context.cond_expr());
var env2 = new Environment(row2, _table.Columns);
var expr2 = new CondExprVisitor(_zmi, env2).Visit(context.cond_expr());
var result = expr1.Zip(expr2).Bind(p =>
{
var res = new NullsVisitor(p).VisitNulls(context.nulls());
if (res == 0)
return new OrderVisitor(p).VisitOrder(context.order()).Just();
return res.Just();
});
return result.Match(i => i, () => 0);
}
_table.Sort(Compare.By<TableRow>(Comparer));
return _table;
}
/// <summary>
/// Visit a parse tree produced by <see cref="QueryParser.order_item"/>.
/// <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 VisitOrder_item([NotNull] QueryParser.Order_itemContext context)
{
return(VisitChildren(context));
}
