Converting a number in words into a number

Function wordToDigits(numInWords As String) As Variant

Dim objSmallNumber As Object     ' dictionay objects
Dim objMidNumber As Object       ' dictionary object
Dim objBigNumber As Object       ' dictionary objects
Dim tempNum As String            ' to lower case the variable passed

Dim numParts, numPart As Variant ' variables to hold fraction of numInWord
Dim bHasBill As Boolean          ' does have a full dollar
Dim bHasChange As Boolean        ' does have change

Dim bigBucket As Double          ' hold multiples of  numbers as we work thru
Dim smallBucket As Double        ' hold numbers as we work thru

Dim preNum As Double             ' hold full bill amount
Dim myNumber As Variant          ' number evaluated. If no prenum, then hold full amount

    bHasBill = False             ' does not have currency unit
    bHasChange = False           ' does not have fraction unit

' ########################################################
' #################### customize here ####################
' ########################################################

Dim CurrencyBill As String     ' currency unit. Leave blank if not needed
    CurrencyBill = "dollars"

Dim CurrencyChg As String      ' currency unit. Leave blank if not needed
    CurrencyChg = "cents"

Dim CurrencyDelim As String    ' decimal delimiter between full and fraction. Leave blank if not needed
    CurrencyDelim = "."

Dim numberSeparator As String  ' word that is valid in spelled number but is not a number example "One Hunred AND Eight"
    numberSeparator = "and"

    Set objSmallNumber = CreateObject("Scripting.Dictionary")
    objSmallNumber.Add "zero", 0
    objSmallNumber.Add "one", 1
    objSmallNumber.Add "two", 2
    objSmallNumber.Add "three", 3
    objSmallNumber.Add "four", 4
    objSmallNumber.Add "five", 5
    objSmallNumber.Add "six", 6
    objSmallNumber.Add "seven", 7
    objSmallNumber.Add "eight", 8
    objSmallNumber.Add "nine", 9
    objSmallNumber.Add "ten", 10
    objSmallNumber.Add "eleven", 11
    objSmallNumber.Add "twelve", 12
    objSmallNumber.Add "thirteen", 13
    objSmallNumber.Add "fourteen", 14
    objSmallNumber.Add "fifteen", 15
    objSmallNumber.Add "sixteen", 16
    objSmallNumber.Add "seventeen", 17
    objSmallNumber.Add "eighteen", 18
    objSmallNumber.Add "nineteen", 19
    
    Set objMidNumber = CreateObject("Scripting.Dictionary")
    objMidNumber.Add "twenty", 20
    objMidNumber.Add "thirty", 30
    objMidNumber.Add "forty", 40
    objMidNumber.Add "fifty", 50
    objMidNumber.Add "sixty", 60
    objMidNumber.Add "seventy", 70
    objMidNumber.Add "eighty", 80
    objMidNumber.Add "ninety", 90

    Set objBigNumber = CreateObject("Scripting.Dictionary")
    objBigNumber.Add "hundred", 100
    objBigNumber.Add "thousand", 1000
    objBigNumber.Add "million", 1000000
    objBigNumber.Add "billion", 1000000000

    
    tempNum = LCase(numInWords) 'lower case
    tempNum = Trim(tempNum) 'remove left right spaces
    tempNum = Replace(tempNum, "-", " ") 'replace any - (example fifty-one)
    
    For Each numPart In objMidNumber
        'add spaces after text like fifty to address situation like fiftyone to make it fifty one
        tempNum = Replace(tempNum, numPart, numPart & " ")
    Next
    
    'remove any double space, that may have been added in the step above or already present
    Do While (InStr(1, tempNum, "  ", vbTextCompare) > 1)
        tempNum = Replace(tempNum, "  ", " ")
    Loop
    
    'break fraction into array based on " " as delimiter
    numParts = Split(tempNum, " ")
    
    bigBucket = 0
    smallBucket = 0
    preNum = 0
    
    ' loop thru each parsed word
    For Each numPart In numParts
            
        If (objSmallNumber.exists(numPart)) Then
            ' add numbers. they might be final or might have a multiplier (like "hundred" next)
            smallBucket = smallBucket + objSmallNumber(numPart)
            tempNum = ""
            
        ElseIf (objMidNumber.exists(numPart)) Then
            ' add numbers. they might be final or might have a multiplier (like "hundred" next)
            smallBucket = smallBucket + objMidNumber(numPart)
            tempNum = ""
            
        ElseIf (objBigNumber.exists(numPart)) Then
            ' a multiplier factor is found.
            bigBucket = bigBucket + smallBucket * objBigNumber(numPart)
            smallBucket = 0
            tempNum = ""
                    
        ElseIf (numPart = CurrencyBill) Then
            ' currency unit found. so next would be fraction
            
            'store total so far. this is before the fraction
            preNum = smallBucket + bigBucket
            smallBucket = 0
            bigBucket = 0
            bHasBill = True 'flag raised, that currency bill unit was found
           
        ElseIf (numPart = CurrencyChg) Then
            ' fraction unit found example "cent". End of the number in word
            bHasChange = True
            Exit For
         
         ElseIf (numPart = numberSeparator) Then
            ' is a valid string in number string but is not a number example "AND"
            'nothing
       
        Else
            MsgBox "Error. Do Not recognise '" & numPart & "' in '" & numInWords & "'"
            wordToDigits = ""
            Exit Function
            
        End If
        
    Next

    ' Add up numbers so far in the que
    myNumber = smallBucket + bigBucket
    
    If (Not bHasBill And Not bHasChange) Then
        ' did not encounter currecny unit or fraction unit
        myNumber = myNumber
        
    ElseIf (bHasBill And Not bHasChange) Then
        ' did encounter currecny unit but did not encounter fraction unit
        myNumber = preNum
    
    ElseIf (Not bHasBill And bHasChange) Then
        ' did not encounter currecny unit but did encounter fraction unit
        myNumber = objSmallNumber("zero") & CurrencyDelim & Right(objSmallNumber("zero") & objSmallNumber("zero") & myNumber, 2)
        
    Else
        ' default, encounter both currency unit and fraction unit
        myNumber = preNum & CurrencyDelim & Right(objSmallNumber("zero") & objSmallNumber("zero") & myNumber, 2)
    End If
    
    wordToDigits = CDbl(myNumber)

End Function