Define hardware tree iteration order
Summary
The initial revision of the hardware tree core classes (#40 (closed)) will not have an enforced iteration order. There is however a general consensus that iteration order should be predictable. There will be two levels of sorting: between types and within types. So one can have gbt gbt vfat vfat vfat
but not gbt vfat vfat gbt vfat
.
The order needs be defined and the core classes need be modified to enforce it.