Ludovic Courtès writes:
> Hi Roel,
>
> I’ve just tried the patch and I think it’s awesome! I’ve also always
> been dissatisfied with what ‘--list-generations’ provides—it’s
> inconvenient as soon as you have more than a handful packages.
>
> Perhaps we could add an optional argument to --list-generations where:
>
> --list-generations
>
> would be equivalent to:
>
> --list-generations=diff
>
> and:
>
> --list-generations=full
>
> would restore the previous behavior. It doesn’t cost much to do that.
>
> WDYT?
That would be great. Currently, the --list-generations already takes a
generation number. How would we deal with the situation where we want
to view the differences between generation 2 and 3 only?
--list-generations=3,diff
That doesn't look appealing to me.
Maybe we could do this instead?:
--list-generations-diff
> I have only minor stylistic comments:
>
> Roel Janssen <r...@gnu.org> skribis:
>
>> +(define (display-profile-content-diff profile number)
>
> Or just ‘display-profile-diff’?
>
>> + "Display the changed packages in PROFILE with generation specified by
>> NUMBER."
>
> “… compared to generation NUMBER”?
>
>> + (define (equal-entry? first second)
>> + (string= (manifest-entry-item first)
>> + (manifest-entry-item second)))
>> +
>> + (define* (display-entries entries #:optional (prefix " "))
>> + (for-each
>> + (match-lambda
>> + (($ <manifest-entry> name version output location _)
>> + (format #t " ~a ~a\t~a\t~a\t~a~%"
>> + prefix name version output location)))
>> + entries))
>
> In general, I find it clearer to define the singular form and inline the
> ‘for-each’:
>
> (define display-entry
> (match-lambda …))
>
> …
>
> (for-each display-entry entries)
>
> Otherwise LGTM!
Right. That does look clearer. I refactored the function further to
the following:
------- BEGIN -------
(define (display-profile-content-diff profile number)
"Display the changed packages in PROFILE compared to generation NUMBER."
(define (equal-entry? first second)
(string= (manifest-entry-item first)
(manifest-entry-item second)))
(define display-entry
(match-lambda
(($ <manifest-entry> name version output location _)
(format #f "~a\t~a\t~a\t~a~%" name version output location))))
(define (display-entries entries prefix)
(for-each (lambda (entry)
(format #t " ~a ~a" prefix (display-entry entry))) entries))
(define (list-entries input)
(manifest-entries (profile-manifest (generation-file-name profile input))))
(define (display-diff profile older newer)
(if (= older 0)
(display-profile-content profile newer)
(begin
;; List newly installed packages.
(display-entries (lset-difference equal-entry?
(list-entries newer)
(list-entries older)) "+")
;; List newly removed packages.
(display-entries (lset-difference equal-entry?
(list-entries older)
(list-entries newer)) "-"))))
(display-diff profile (previous-generation-number profile number) number))
------- END -------
The thing with `display-entries' is because I cannot pass two arguments
in the function used in the `for-each', and the prefix for `installed'
or `removed' differs, I cannot remove it that easily :-).
Kind regards,
Roel Janssen
