Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub MyErrorHandler(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      '// Check if the specific 'FloatInvalid' error was raised
      If uc.Error.Code = ErrorCode.FloatInvalid Then
         Console.WriteLine("Error: The calculation resulted in an invalid number (e.g., square root of a negative).")
         '// Stop further processing
         uc.Error.Response = ErrorHandlerResponse.Abort
      End If
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      '// Register the custom error handler
      uc.Error.AddHandler(AddressOf MyErrorHandler)
      
      '// Tell uCalc to raise an error instead of returning 'nan'
      uc.Error.TrapOnInvalid = true
      
      '// This will now trigger our custom error handler's message
      uc.EvalStr("sqrt(-4)")
   End Sub
End Module