AppsheetEpplus/FormulaParsing/Excel/Functions/Information/IsErr.cs

using System.Collections.Generic;

namespace AppsheetEpplus;

public class IsErr : ErrorHandlingFunction {
  public override CompileResult Execute(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    var isError = new IsError();
    var result = isError.Execute(arguments, context);
    if ((bool)result.Result) {
      var arg = GetFirstValue(arguments);
      if (arg is ExcelDataProvider.IRangeInfo info) {
        var e = info.GetValue(info.Address._fromRow, info.Address._fromCol) as ExcelErrorValue;
        if (e != null && e.Type == eErrorType.Na) {
          return CreateResult(false, DataType.Boolean);
        }
      } else {
        if (arg is ExcelErrorValue value && value.Type == eErrorType.Na) {
          return CreateResult(false, DataType.Boolean);
        }
      }
    }
    return result;
  }

  public override CompileResult HandleError(string errorCode) {
    return CreateResult(true, DataType.Boolean);
  }
}