MSISDN Parser Function in VBA

This document outlines a VBA function that parses an MSISDN (Mobile Station International Subscriber Directory Number) to extract the country and state information based on predefined mappings.

Overview

The function utilizes a dictionary to map country codes and state codes from the MSISDN. It provides robust error handling and input validation.

Code Implementation

Option Explicit

' Imports
' No additional libraries are needed for this function

' Function to parse MSISDN number into country and state
' Parameters:
'   - msisdn (String): The MSISDN number to be parsed
' Returns:
'   - A dictionary containing country and state for the provided MSISDN
' Raises:
'   - Error if the MSISDN format is invalid or if not found in the mapping
Function ParseMSISDN(msisdn As String) As Object
    Dim mappingDict As Object
    Set mappingDict = CreateObject("Scripting.Dictionary")

    ' Initial mapping of country codes
    mappingDict.Add "1", "USA"  ' North America
    mappingDict.Add "44", "UK"   ' United Kingdom
    mappingDict.Add "91", "India" ' India
    mappingDict.Add "61", "Australia" ' Australia
    mappingDict.Add "81", "Japan"  ' Japan
    ' Extend with more mappings as necessary

    ' Input validation: Check for correct format (numeric only)
    If Not IsNumeric(msisdn) Or Len(msisdn) < 2 Then
        Err.Raise vbObjectError + 1, "ParseMSISDN", "Invalid MSISDN format."
    End If

    Dim countryCode As String
    Dim countryName As String
    Dim stateName As String

    ' Extract country code from MSISDN
    If Len(msisdn) >= 2 Then
        countryCode = Left(msisdn, 2) ' Getting first two digits as country code
    End If

    ' Check if country code exists in the mapping
    If mappingDict.Exists(countryCode) Then
        countryName = mappingDict(countryCode)
        stateName = "" ' Placeholder for state, if available

        ' Return the results in a dictionary
        Dim resultDict As Object
        Set resultDict = CreateObject("Scripting.Dictionary")
        resultDict.Add "Country", countryName
        resultDict.Add "State", stateName ' Can be enhanced with actual logic to get states
        Set ParseMSISDN = resultDict
    Else
        ' Raise error if country code not found
        Err.Raise vbObjectError + 2, "ParseMSISDN", "Country code not found in mapping."
    End If
End Function

Explanation of the Code

1. Mapping Dictionary Initialization:

   • A Scripting.Dictionary is created to hold country code mappings.

2. Input Validation:

   • The function checks if the input is numeric and has a valid length. If not, it raises an error.

3. Country Code Extraction:

   • The country code is extracted by taking the first two digits of the MSISDN.

4. Validation Against Mapping:

   • The country code is checked against the dictionary. If found, it retrieves the corresponding country.

5. Return Structure:

   • The function returns a dictionary containing the country and state.

Usage Example

Here's how you can use the ParseMSISDN function within a VBA module:

Sub TestParseMSISDN()
    Dim parsedInfo As Object
    On Error GoTo ErrorHandler

    ' Example MSISDN
    Dim exampleMSISDN As String
    exampleMSISDN = "14155552671" ' MSISDN for USA

    ' Parsing MSISDN
    Set parsedInfo = ParseMSISDN(exampleMSISDN)

    ' Displaying results
    MsgBox "Country: " & parsedInfo("Country") & vbCrLf & "State: " & parsedInfo("State")

    Exit Sub

ErrorHandler:
    MsgBox "Error: " & Err.Description
End Sub

Conclusion

This VBA function effectively parses MSISDN numbers for country identification using a mapping dictionary, implementing error handling and validation for improved reliability. For advanced topics such as managing larger datasets or additional state mappings, consider exploring additional resources on the Enterprise DNA platform.