[xmonad] DynamicWorkspaceOrder of a tag

[Jonas]

Hello everyone,

(I am an "awesome" convert new to xmonad and I hope this is the right
place to ask this question and I am not unknowingly violating some
etiquette. If so, please forgive and tell me.)

I am using DynamicWorkspaceOrder and want to know the number of a
workspace in this order.
Basically I am looking for the number that "withNthWorkspace" would use.
So given a tag, how can I get its place in the DynamicWorkspaceOrder?

Alternatively how can I get a list of all the workspaces in their
DynamicWorkspaceOrder?
Basically I need to replace the following with something that respects
DynamicWorkspaceOrder:
myWorkspaces :: [WorkspaceId]
myWorkspaces = ["1:main", "2:www", "3:sys"]

What I am trying to achieve is to display the number of a workspace
next to its name in my dmenu bar, so I know which key binding to use
to get there. This would obviously be especially useful for dynamic
workspaces. The key bindings are generated via (the
DynamicWorkspaceOrder version of) "withNthWorkspace".

An alternative might be to modify DynamicLogWithPP but I'd rather not
go there if I can avoid it (and I would not know how to do it either).

Thanks a lot for your help,
Jonas