CODEWITHSUNDEEP
variablesvbscriptexpression
Eugene A
Eugene A

Reputation: 330

VBS: Variable not getting assigned a value via recursive expression

I am having an issue with VBS variable value assignment:

Dim varName  
varName = function(x, y)
varName = function(x, y)

function is a recursive function, which calls itself:

Function function(x, y)
    If IsObject(dicColumnIndices) Then
        function = CInt(dicColumnIndices.Item(y))
    Else
        Set oCDSGrid = %MyAppObject%
        Set dicColumnIndices = CreateObject("Scripting.Dictionary")
        intColumnCount = oCDSGrid.ActiveSheet.Columns.Count
        For i = 0 To intColumnCount - 1
            dicColumnIndices.Add oCDSGrid.ActiveSheet.Columns.Item(i).Label, i
        Next

        function x, y
    End If
End Function

As far as I can see, the variable value assignment only happens on the second try. I figured it has something to do with my function recursively calling itself (the issue is gone in case I remove the recursive call), but I shall very much like to learn what are the roots of this behaviour.

I looked up both StackOverflow and the Internet with no luck.

Edit: In order to solve this issue, I had to remove the recursive call:

Function function(x, y)
If IsObject(dicColumnIndices) Then
    function = CInt(dicColumnIndices.Item(y))
Else
    Set oCDSGrid = %MyAppObject%
    Set dicColumnIndices = CreateObject("Scripting.Dictionary")
    intColumnCount = oCDSGrid.ActiveSheet.Columns.Count
    For i = 0 To intColumnCount - 1
        dicColumnIndices.Add oCDSGrid.ActiveSheet.Columns.Item(i).Label, i
    Next

    function = CInt(dicColumnIndices.Item(y))
End If
End Function

Edit 2: Finally, with help from MSDN I got the wrong part - it is the second call 

function x, y

which returns the value into nothing, must be changed to: 

function = function x, y

Thanks everyone!

Upvotes: 0

Views: 1230

Answers (1)

Ekkehard.Horner
Ekkehard.Horner

Reputation: 38745

A function shouldn't be called function, and varname is a lousy name for a variable. More to the point: In VBScript a function isn't a function (does not return something) if you don't 'assign to the function name':

  Dim s : s = "abcdefg"
  Dim l : l = recLen(s)
  WScript.Echo "recursive length of", qq(s), "=>", l, CStr(l = Len(s))

  Function recLen(s)
    If "" = s Then
       recLen = 0
    Else
       recLen = 1 + recLen(Mid(s, 2))
    End If
  End Function

(The length of an empty string is 0; for longer strings it's 1 + the length of the string's 'tail')

Update (thanks to AutomatedChaos):

Function qq( vStringable )
  qq = """" & vStringable & """"
End Function

Update II (to answer Eugene's question in comment):

To make a function to return something, you'll have to assign the value to return to a variable having the same name as the function. Your original code didn't (even if the name "function" was replaced by the 'real' name).

Upvotes: 1

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