Re: Patches to implement system roll-back and switch-generation

[Ludovic Courtès]

Hi Chris,

Chris Marusich <address@hidden> skribis:

> address@hidden (Ludovic Courtès) writes:
>> We can now avoid monadic procedures by using the declarative counterpart
>> of the monadic API.  That is, we could write:
>>
>>   (define (grub-configuration-file …)      ;normal proc
>>     (computed-file "grub.cfg" builder))
>>
>> instead of:
>>
>>   (define (grub-configuration-file …)      ;monadic proc
>>     (gexp->derivation "grub.cfg" builder))
>>
>> I would welcome such changes.
>>
>
> That's an interesting idea.  However, in this case, I think we need to
> pass the build options (from the parsed command-line arguments) along
> somehow.  How should we set the build options when using the declarative
> 'computed-file' procedure?  It seems like the most obvious way would be
> to pass the build options in as arguments to the 'computed-file'
> procedure, but is there a better way?

Which build options?  There’s a direct correspondence between, say,
‘gexp->derivation’ and ‘computed-file’ and the arguments are essentially
the same.  Unless I’m overlooking something (again!), the change I
suggest above is a mechanical change.

HTH,
Ludo’.