Matthias Benkmann wrote:
I have a problem with a recursive function in one of my macros. The function
is supposed to either return an array of strings or Empty (in case there's
not enough input data). However, under some circumstances the function
mysteriously returns Object/Null instead of Variant/Empty. I'd like to know
if this is a bug in OOo (I tested 1.9.122 and 1.9.125) or some
misunderstanding on my part. The following is a chopped down version of my
code:
Sub Main
Dim n(1) as String
n(0) = " "
n(1) = " "
Dim a as Variant
f(Array(60,10,1,12,20,10,25,30), n(), 0, 76)
End Sub
Function f(splitInfo() as Variant, daten() as String, i as Long, j as Long)
as Variant
If i > UBound(daten) Then
Exit Function
End If
Dim ret() as String
for k = 0 to UBound(splitInfo)
restLen = Len(daten(i)) - j
Dim splitPos as Long
splitPos = splitInfo(k)
If splitPos <= restLen Then
j = j + splitPos
Else
st = Right(daten(i), restLen)
i = i + 1
j = 0
sta = f(Array(splitPos - restLen), daten, i, j)
If IsNull(sta) Then
MsgBox("This is impossible!")
Exit Function
End if
End If
next k
f = ret()
End Function
As you can see there are only 2 ways out of the function f(). The first one
is an "Exit Function" that is called without an assignment to the function's
return value. On this code path the function is supposed to return
Variant/Empty. The 2nd way out of the function is after the assignment f =
ret() which sets the return value to an array of string. There should be no
way for the function to return Variant/Null, so the condition IsNull(sta)
should never be true. But strangely it is at some point. If I call the
function directly from Main with the exact same parameters as the recursive
call that returns Null, I get Empty as it should be. So it seems that Null
is returned only in the recursive case.
Can someone give me a clue what's going on? Is this a bug? Should I file a
bug report?
Matthias
I don't suppose that you can provide an example that causes the
problem... I tried to use the supplied example and there are issues. I
added some error handling and found out that errors were generated and
variables are not defined. This is likely to affect the results. In the
following code, in which I tried to NOT change the meaning of the
variables, I added some error handling that is called.
Option Explicit
Sub Main
Dim n(1) as String
n(0) = " "
n(1) = " "
Dim a as Variant
f(Array(60,10,1,12,20,10,25,30), n(), 0, 76)
End Sub
Function f(splitInfo() As Variant, daten() As String, i As Long, j As
Long) As Variant
Dim ret() As String
Dim k As Long
Dim splitPos As Long
Dim restLen As Long
Dim st As String
Dim sta
On Error Goto BadError
If i > UBound(daten()) Then
Print "Exit at point 1"
Exit Function
End If
For k = 0 To UBound(splitInfo())
REM dataen(i) is always of length 1 in this example.
REM j starts off as length 76, so restLen is likely to spend some
REM time with a negative value.
restLen = Len(daten(i)) - j
splitPos = splitInfo(k)
If splitPos <= restLen Then
j = j + splitPos
Else
REM We generate an error when restLen = -75.
st = Right(daten(i), restLen)
i = i + 1
j = 0
sta = f(Array(splitPos - restLen), daten, i, j)
If IsNull(sta) Then
Print "Exit at impossible point 2"
Exit Function
End if
End If
Next k
'Print "Exit at point 3"
f = ret()
Exit Function
BadError:
Print "There was a bad error"
On Error Goto 0
Print "LB = " & LBound(daten()) & " UB = " & UBound(daten())
Print "i = " & i & " restLen = " & restLen
End Function
--
Andrew Pitonyak
My Macro Document: http://www.pitonyak.org/AndrewMacro.sxw
My Macro Book: http://www.hentzenwerke.com/catalog/oome.htm
Free Info: http://www.pitonyak.org/oo.php
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