Dynamic Menu from folders - menu

Question

In my program I want to create a menu with submenus based on a folder and its subfolders.
The first function menu_fromfiles works fine.
But the second function menu_fromfolders keeps giving me an error: submenu does not exist - and I can't figure it out. Any clues?
Here is my code:
#SingleInstance force
RButton::
menu_fromfolders("filelist", "File List", "c:\test", "*.txt", "thismenu")
menu, thismenu, show
Return
-------------------------------------------------------------------
menu_fromfolders(submenuname, menutitle, whatdir, filemask="*", parentmenu="", whatsub="DONOTATHING"){
global
loop, %whatdir%\*, 1, 0
{
if(file_isfolder(A_LoopFileFullPath)){
menu_fromfiles(a_loopfilename, a_loopfilename, A_LoopFileFullPath, filemask, "", whatsub)
menu, %submenuname%, add, %a_loopfilename%, :%a_loopfilename%
}else{
menu, %submenuname%, add, %a_loopfilename%, %whatsub%
}
}
if(parentmenu){
menu, %parentmenu%, add, %menutitle%, :%submenuname%
}
return submenuname
}
menu_fromfiles(submenuname, menutitle, whatdir, filemask="*", parentmenu="", whatsub="DONOTATHING"){
loop, %whatdir%\%filemask%, 0, 0
{
menu, %submenuname%, add, %a_loopfilename%, %whatsub%
}
if(parentmenu){
menu, %parentmenu%, add, %menutitle%, :%submenuname%
}
return submenuname
}
;returns true if the item is a folder, false if is a file
file_isfolder(whatfile){
lastchar := substr(whatfile, 0, 1) ;fetch the last character from the string
if(lastchar != "\")
whatfile := whatfile . "\"
if(fileexist(whatfile))
return true
}
;empty command for the menu title
DONOTATHING:
return
Here is a more detailed error message:
Error in ...script.ahk
Submenu does not exist
-->menu, %submenuname%, add, %a_loopfilename%, :%a_loopfilename%
[update]
Please see my solution below. You can find the complete and refined script here: http://www.autohotkey.com/board/topic/95219-dynamicfilemenuahk/

Answer 1

Ah, figured it out.
When the menu_fromfiles loop searches for files, if no files matching the mask are discovered, it does not add anything to the menu.
Now, you can't create a submenu with nothing in it. So if no items were added to the submenu, no submenu is created.
It was working intermittently only for directories that had folders containing files matching the mask. When there were no matching files (or the directory was empty), the function was trying to add a non-existent menu.
The solution is to add a method of detecting that a menuitem was, indeed created:
menu_fromfiles(submenuname, menutitle, whatdir, filemask="*", parentmenu="", whatsub="DONOTATHING"){
menucount := 0
loop, %whatdir%\%filemask%, 0, 0
{
menu, %submenuname%, add, %a_loopfilename%, %whatsub%
menucount++
}
if(parentmenu && menucount){
menu, %parentmenu%, add, %menutitle%, :%submenuname%
}
return submenuname
}
If anyone is interested, I refined this code to display all the folders. You will find the full script here: http://www.autohotkey.com/board/topic/95219-dynamicfilemenuahk/