public override Table VisitWhere_clause(QueryParser.Where_clauseContext context)
{
var result = new Table(_table);
foreach (var row in _table)
{
var env = new Environment(row, _table.Columns);
var value = new CondExprVisitor(_zmi, env).Visit(context.cond_expr());
if (value.HasValue && value.Val.Value.GetBoolean())
result.AppendRow(row);
}
return result;
}
/// <summary>
/// Visit a parse tree produced by <see cref="QueryParser.where_clause"/>.
/// <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 VisitWhere_clause([NotNull] QueryParser.Where_clauseContext context)
{
return(VisitChildren(context));
}
