Nikita Karetnikov <nik...@karetnikov.org> skribis:
>> Also, I think it should process fields, and return an alist, or even
>> better, a ‘gnu-package-descriptor’ record (say).
>>
>> (define-record-type <gnu-package-descriptor>
>> gnu-package-descriptor?
>> (gnu-package-descriptor name logo-url doc-category ...)
>> ...
>> )
>>
>> (official-gnu-packages)
>> => (#<gnu-package-descriptor name: "guix" logo-url: "http://..."; ...#> ...)
>>
>> WDYT?
>
> Oh, I forgot about this when I was writing the attached patch. Is it
> fine? Should I rewrite it using records?
Yes please, that would be better.
> I guess that it will work faster if I use 'cons' in 'loop' instead of
> 'append'. Is it worth it?
In general yes: always cons, and reverse at the end (that makes the
complexity linear.)
> Examples:
>
> scheme@(guile-user)> ,use (guix gnu-maintenance)
> scheme@(guile-user)> (find-packages "guix")
> $1 = (("package: guix" "logo: /software/guix/graphics/guix-logo.small.png"
> "doc-category: Sysadmin" "doc-summary: Managing installed software packages
> and versions" "doc-url: none" "gplv3-status: should-be-ok" "activity-status:
> newpkg/20121117"))
Since it has to read all the package file, I’d rather keep an
‘official-gnu-packages’ that would return a list of all the packages
(we’re talking about less than 1 MiB of RAM), and then use ‘filter’ on
that.
(Alternately, ‘official-gnu-packages’ could be a stream (in the sense of
(ice-9 stream)), but then there’s going to be issues with connection
timeouts, so a plain old list is better.)
> + "Return an input port with the textual data at URI, a string."
> + (let*-values (((resp port)
> + (http-get* (string->uri uri)))
This code is run by the user’s Guile, which may be older than 2.0.7
(‘http-get*’ was introduced in 2.0.7), so you can’t rely on it.
What you can do is something along the lines of what (guix build
download) does, but always return a port. Maybe there’s a way to share
code.
A couple of stylistic comments:
> + (define (group-packages port state)
> + ;; Return a list of packages.
> + (let ((line (read-line port)))
> + (define (loop str)
> + (match str
> + ('""
> + (group-packages port (append state '(()))))
> + (str
> + (group-packages port (append (drop-right state 1)
> + (list (append (last state)
> + (list str))))))))
It’s called ‘loop’ but it doesn’t loop.
I’d rather change ‘group-packages’ to ‘read-package-fields’ or something
like that.
> + (filter (lambda (lst)
> + (not (null-list? lst)))
> + state)
(remove null-list? state)
> + (and=> (regexp-exec package-line-rx (first sublst))
> + (lambda _
> + sublst)))
identity
Thanks,
Ludo’.
