Re: [PATCH] guix package: Add '--delete-generations'.

[Ludovic Courtès]

Nikita Karetnikov <address@hidden> skribis:

>> “Delete the generations matching @var{patterns} or ... when omitted.”
>
>> Or what actually?  I would expect it to delete all the generations but
>> the current one when PATTERN is omitted, right?
>
> ‘--delete-generations’ deletes everything and points the profile to the
> zeroth generation.  There are range patterns if you want to keep the
> current generation.  I prefer the current behavior.

Oh.  I’d prefer if it would delete all generations but the current one.

That’s a fairly useful pattern: suppose you want to make space on your
disk (and you know you won’t need to roll back), it’d be handy to run:

  guix package --delete-generations && guix gc

Whereas if you have to use ranges, you end up doing something like:

  guix package --list-generations |grep ^G
  # check the number of the last generation...
  guix package --delete-generations=..42 && guix gc

Conversely, removing *all* the generations is something you’re unlikely
to do very often.

WDYT?

>> No need for ‘begin’ in the body of a ‘cond’ clause.
>
> Why?  Is it specified somewhere?  Or is it easier to read?

It’s easier to read if there’s no extra ‘begin’ IMO, and it’s specified
in R5RS & co. (info "(r5rs) Expression").

>> Why is there this big hunk?  If it’s just reindenting, could you arrange
>> to remove this hunk?
>
> I couldn’t avoid reindenting since the word “cond” is longer than “if.”
> However, I used this opportunity to move a couple of things around.  I’d
> prefer to keep this change.

OK fine.  I just wanted to make sure this was only reindenting.

> Frankly, I think that the module should be reorganized at some point
> (especially the ‘guix-package’ function).  I don’t like that functions
> don’t fit on the screen.

Agreed (though individual functions do fit on the screen; the top-level
function is pretty much a module ;-)).

The profile-related functions will go in a (guix profile) module as soon
as you’re done with --delete-generations.

Thanks,
Ludo’.