I'd like to rewrite ShowFormula Function (long time ago) - excel

Question

The following code has kicked around with me for many years. I do not know where I picked it up and for the most part it worked, when it worked. However, I have tried to use it on a new document. It worked once then didn't work again. I have tried to add the VB reference to Regular Expressions 5.5 but that was not correct. I was hoping for an easy fix.
The concept of the function was to display the content of a cell as an evaluated equation. It was to "show my work" so to speak so that in complex sheets, checking would be easier.
Unfortunately, the vbscript in the function is a black box to me.
Old Code
Option Explicit
Function SF(r As Range, Z As Integer) As String
Debug.Print r, Z
Const crep As String = "(([A-Za-z0-9_]+|'[^']+')!)?\$?[A-Z]{1,2}\$?[0-9]+"
Const mrep As String = "(([A-Za-z0-9_]+:[A-Za-z0-9_]+|'[^']+:[^']+')\!)|(\$?[A-Z]{1,2}\$?[0-9]+:\$?[A-Z]{1,2}\$?[0-9]+)"
Dim v As Variant, n As Long
Dim regex As Object, matches As Object, m As Object
SF = Mid(r.formula, 2)
Set regex = CreateObject("vbscript.regexp")
regex.Global = True
regex.Pattern = mrep
Set matches = regex.Execute(SF)
If matches.Count > 0 Then Exit Function
regex.Pattern = crep
Set matches = regex.Execute(SF)
n = matches.Count - 1
For n = n To 0 Step -1
Set m = matches.Item(n)
If InStr(m.Value, "!") = 0 Then v = Evaluate("'" & r.Parent.Name & "'!" & m.Value)
If IsNumeric(Val(v)) = True Then
v = Application.WorksheetFunction.Round(v, Z)
End If
SF = Left(SF, m.FirstIndex) & CStr(v) & _
Mid(SF, m.FirstIndex + m.Length + 1)
Next n
SF = "{ =" & SF & "}"
End Function
Updated Code-ish
Function SF(r As Range, Z As Integer) As String
Debug.Print r, Z
Const crep As String = "(([A-Za-z0-9_]+|'[^']+')!)?\$?[A-Z]{1,2}\$?[0-9]+"
Const mrep As String = "(([A-Za-z0-9_]+:[A-Za-z0-9_]+|'[^']+:[^']+')\!)|(\$?[A-Z]{1,2}\$?[0-9]+:\$?[A-Z]{1,2}\$?[0-9]+)"
Dim v As Variant, n As Long
SF = Mid(r.formula, 2)
n = InStr(SF, crep)
While n > 0
If InStr(Mid(SF, n), "!") = 0 Then
v = Evaluate("'" & r.Parent.Name & "'!" & Mid(SF, n, InStr(SF, crep) - n + Len(crep)))
If IsNumeric(Val(v)) = True Then
v = Application.WorksheetFunction.Round(v, Z)
End If
SF = Left(SF, n - 1) & CStr(v) & Mid(SF, n + Len(crep) + 1)
End If
n = InStr(SF, crep)
Wend
SF = "{ =" & SF & "}"
End Function
I can assume that this is not the first time this type of code has been written. Above is an attempt but the cell address is displayed and not the cell value. When referencing a named cell, it just shows the cell name.
Any thoughts? Am I going in the correct direction?