VBA Modules and passing arguments - vba

Question

I have a module that can be called from any part of my application to check if a particular font is installed on the users system, and if not - install the font and check again before continuing
Main Applicaton
if RequiredFont.Run(strFontName) = FALSE Then '(error message and exit sub)
Module "RequiredFont"
Public Function Run(Font As String) As Boolean
if check(Font) = FALSE Then
Run = FALSE
Install(Font)
if check(Font) = TRUE Then Run = TRUE
Else
Run = TRUE
End If
Private Function Check(Font as String) as Boolean
'code to check the font exists on the users localmachine, returns true/false
End Sub
Private Sub Install(Font as String)
'code to install the font on the users localmachine,
End Sub
My first question is:
Is the best way to make arguments available to all functions and subs, to pass them through each time I call? (as shown above).... or is there a simple way to declare an argument as variable to the whole module when Run() is called?
My Second Question is:
Is there a way I can avoid Run() alltogether and just call the module name "RequiredFont" directly, I remember that in other languages, calling a sub by a certain name would automatically run that sub when the module is called
Thank You
EDIT - This is how my code looks now:
Private FontName As String
Private FontFile As String
Public Function Run(strFontName As String, strFontFile As String) As Boolean
FontName = strFontName
FontFile = strFontFile
Run = False
If CheckFont() = False Then InstallFont
If CheckFont() = True Then
Run = True
Else
'message error"
End If
End Function
Private Function CheckFont() As Boolean
'code to check if the font is installed
On Error Resume Next
'Create a temporary StdFont object
With New StdFont
' Assign the proposed font name
.Name = FontName
' Return true if font assignment succeded
If (StrComp(FontName, .Name, vbTextCompare) = 0) = False Then
CheckFont = False
Else
CheckFont = True
End If
End With
End Function
Private Sub InstallFont()
' code to install the font
MsgBox "You need the following font installed to continue." _
& vbNewLine _
& vbNewLine & "'" & FontName & "'" _
& vbNewLine _
& vbNewLine & "Click OK to launch the font. Please click the INSTALL button at the top"
OpenFile (PATH_TO_FONTS & FontFile)
End Sub

Answer 1

Using function arguments is a good coding practise, that way you know exactly what goes in and what goes out a function.
You can however use a global variable, which would be set once when Run is called and still be accessible to the other functions.
'could also be Private to hide it from other modules
Public myFont As String
Public Function Run(Font As String) As Boolean
myFont = Font
'...
End Sub
Private Function Check() as Boolean
' you can access myFont here
End Sub
Private Sub Install()
'idem
End Sub
Regarding your second question, I don't think you can.

Answer 2

You can declare optional functions, and set defaults:
Public Function fxMyFunction _
(Optional lngProj As Variant, _
Optional strFruit As Variant = "banana", _
Optional booTest As Boolean = False) As String
'' IsMissing requires that lngProj be a Variant
booNoProject = IsMissing(lngProj)
fxMyFunction = strFruit
End Function
The Optional arguments must follow non-optional arguments.
About functions that "run on inclusion"
You do have to call functions and subs by name. There is no "self-running function" feature for a VBA standard module. VBA "includes" all modules on compiling.
VBA class modules are where you will find the equivalent of constructors. Investing in VBA's version of object-orientation doesn't seem helpful for your current need. If you do go that direction, some aspects will start looking familiar to you (though perhaps just enough to get frustrating, as OO remains a feature that was added later and looks the part).

Answer 3

As #z states, you can use a global variable, although this is bad practice.
Regarding question 2, you can give your function a unique name and omit naming your module to run it, e.g.
findOrInstallFont(Fontname)