Forklaring af kode

Følgende kode erstatter nogle tags med egentlige variabler - jeg forstår dog ikke, hvorledes den gør det. Kan I forklare koden nærmere?

Function ExcelMerge(TemplateFil As String, DocName As String) As String

undervejs
 
  Dim objExcel As Object
  Dim xls As Object 'Excel.Document
  Dim isExcelRunning As Boolean
  Dim SQL As String, stErr As String, SearchTag As String, ReplaceTxt As String


  SysFlettefelterDatoData

 
  On Error Resume Next
  Set objExcel = GetObject(, "Excel.Application")
  If Err.Number = 429 Then
    Set objExcel = CreateObject("Excel.Application")
    isExcelRunning = False
    Err.Clear
  Else
    isExcelRunning = True
  End If
 
  Set xls = objExcel.Documents.Add(TemplateFil)
 
  On Error GoTo errHandler
 

  Dim Flet As ADODB.Recordset
  Set Flet = New ADODB.Recordset
  SQL = "SELECT Felt, FletVaerdi FROM SysFlettefelter WHERE Felt Is Not Null and Felt <> '<Markør>' and Felt <> '<curser>'"
  Flet.Open SQL, CurrentProject.Connection, adOpenKeyset, adLockReadOnly


  While Not Flet.EOF
    ReplaceTxt = Nz(Flet!FletVaerdi, "")
    ReplaceTxt = Replace(ReplaceTxt, Chr(10), "")
    WordSearchAndReplace xls, Flet!Felt, ReplaceTxt
    Flet.MoveNext
  Wend
  Flet.Close
 

  If WordSearch(xls, "<Markør>") Then
    xls.Application.Selection.Delete Unit:=1, Count:=1
  Else
    If WordSearch(xls, "<cursor>") Then xls.Application.Selection.Delete Unit:=1, Count:=1
  End If
 
  xls.SaveAs DocName
  xls.Close -1  'wdSaveChanges
 
  If Not isExcelRunning Then objExcel.Quit True
  stErr = ""
 
ExitHere:
  ExcelMerge = stErr
  Exit Function

errHandler:
  stErr = "Error: " & Err.Description
  Exit Function

End Function