device syntax again

[Hollis Blanchard]

I'd like to discuss device syntax again. Let me start by giving an 
example. When a client is booted on an OF-based machine, it can find 
out what the booted device and path was. This is the /chosen/bootpath 
property. Here is the bootpath property from a briQ I just booted:
        ok > boot net:,grubof.chrp
        bootpath = /address@hidden/address@hidden
I would like to load a config file from the same location, so I should 
set the GRUB environment variable "prefix".

(Remember: the original problem I had regarding device syntax was use 
of the comma in device paths. OF paths sometime contain commas, but 
that confuses GRUB's parser, which was written when all it had to worry 
about was the devices on a PC.)

What should I set prefix to if the bootpath property has a comma in it? 
It is not possible to ask the user to reboot and create a devalias for 
this device. Aside from the obvious usability issues, the devalias is 
actually expanded to its true path for the bootpath property. You'll 
notice above I used the alias "net", but bootpath was the full 
"/address@hidden/address@hidden".

-Hollis