VB6 isIn function

Private Sub Form_Load()
    
    a = Array(1, 2, 3, 4, 5)
    Set b = New Collection
    b.Add 1
    b.Add 2
    b.Add 3
    
    Dim index
    
    Debug.Print "Number variant array test: " & isIn(4, a, index)
    Debug.Print index

    Debug.Print "Number collection test: " & isIn(3, b, index)
    Debug.Print index

    Debug.Print "String test: " & isIn("test", "this is my test string!", index)
    Debug.Print index
    
    Set b = New Collection
    b.Add New Form1
    b.Add Me
    
    Debug.Print "Object collection test: " & isIn(Me, b, index)
    Debug.Print index
    
    Debug.Print "double test: " & isIn(3.14, Array(7.15, 8, 3.14), index)
    Debug.Print index
    
End Sub




Function isIn(needle, haystack, Optional ByRef index) As Boolean
    Dim t As String, j As String, x
    Dim i As Long
    
    On Error GoTo hell
    'string or variant are treated as strings and index = instr
    'arrays will walk all elements, index will be found array index, search as above
    'collections as above index col index, also supports object types..
    'other datatypes
    index = -1
    t = TypeName(haystack)
    
    If t = "String" Or t = "Variant" Then
        index = InStr(1, haystack, needle, vbTextCompare)
        If index > 0 Then isIn = True
    ElseIf InStr(t, "()") > 0 Then 'its an array
        For i = LBound(haystack) To UBound(haystack)
            j = TypeName(haystack(i))
            If j = "String" Or t = "Variant" Then
                 index = InStr(1, haystack(i), needle, vbTextCompare)
                 If index > 0 Then
                    isIn = True
                    index = i
                    Exit For
                 End If
            Else
                If needle = haystack(i) Then
                    isIn = True
                    index = i
                    Exit For
                End If
            End If
        Next
    ElseIf t = "Collection" Then
        i = 0
        For Each x In haystack
            i = i + 1
            j = TypeName(x)
            If IsObject(needle) And IsObject(x) Then
                 If ObjPtr(needle) = ObjPtr(x) Then
                    isIn = True
                    index = i
                    Exit For
                 End If
            ElseIf j = "String" Or t = "Variant" Then
                 index = InStr(1, haystack(i), needle, vbTextCompare)
                 If index > 0 Then
                    isIn = True
                    index = i
                    Exit For
                 End If
            Else
                If needle = x Then
                    isIn = True
                    index = i
                    Exit For
                End If
            End If
        Next
    Else
        If needle = haystack Then
            isIn = True
            index = 0
        End If
    End If
                    
    Exit Function
    
hell:
    isIn = False
    index = -2
    
End Function