[PATCH] RFC: nvedit: support doing one (extra) expansion of the value in "env set"

[Rasmus Villemoes]

On 11/02/2020 22.20, Rasmus Villemoes wrote:
> On 11/02/2020 17.30, Wolfgang Denk wrote:

>>> This forces some scripts to needlessly duplicate logic and hardcode
>>> assumptions. For example, in an A/B scheme with three variables
>>>
>>> BOOT_ORDER # Either "A B" or "B A" depending on which slot was last updated
>>> BOOT_A_LEFT # 0..3
>>> BOOT_B_LEFT # 0..3
>>>
>>> when one needs to determine the slot to boot from, one does something
>>> like
>>
>> Well, there _are_ other ways...
> 
> Please do tell. How can I avoid code duplication and access a variable
> whose name I generate by string concatenation/variable interpolation?

Btw., I also considered implementing this as a separate subcommand "env
get <dest> <varname>", then I could do "env get result
BOOT_${slot}_LEFT". That wouldn't be quite as powerful as "env set -E",
but I think sufficient for my use case(s).

Rasmus