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[bug#49597] [PATCH core-updates 00/15] Ajust packages to label-less inpu
[bug#49597] [PATCH core-updates 00/15] Ajust packages to label-less input style
Mon, 19 Jul 2021 18:47:54 +0200
Ludovic Courtès schreef op ma 19-07-2021 om 16:50 [+0200]:
> > In the example you gave, both search-input-file and the original
> > 'string-append'
> > and 'assoc-ref' look convenient to me, though the latter more so than the
> > other,
> > and a third variant could be
> > #$(file-append (this-package-native-input "openmpi") "/lib/libmpi.so")
> > which avoids 'string-append' and 'assoc-ref'.
> Yes, but you’re still relying on the name, “openmpi”.
> If I do:
> (inherit thing)
> (inputs `(("mpich" ,mpich)
> ,@(delete "openmpi" (package-inputs thing)))))
> … then you have a problem: ‘this-package-input’ won’t find “openmpi”.
> It’s a real, common use case. That’s why we need to be careful about
> the idioms we promote.
Then you could do:
(inputs `(("openmpi" ,mpich) ; use "openmpi" label
,@(delete "openmpi" (package-inputs thing)))))
or just use "mpi" in the original and new package as input label,
but that doesn't mesh well with eventually removing input labels.
Myself, I don't mind input labels much. They look like arguments to
a procedure to me, albeit with an unusual syntax for referring to
> > (I prefer explicitely writing in the package definition in which input a
> > file
> > will be found, as a kind of documentation, though in this case it probably
> > doesn't really matter.)
> Yeah, I like that too. OTOH, ‘search-input-file’ has the advantage that
> it errors out if the file is not found, whereas
> (string-append (assoc-ref inputs "foo") "bar")
> always “works” and problems occur possibly much later, at run time.
I'd suggest using #+/#$(file-append (this-package-[native]-input "foo") "/bar"
instead of (string-append (assoc-ref ...) ...).
I think I have a method for explicitely choosing which input to use,
using package names instead of labels, that still works nicely with
(define* (lookup-libmpi-library package)
;; open-coding could be avoided by adding a 'is-mpi-library?'
;; package property and using that instead of hard-coding a list
;; of package names
(file-append (or (lookup-package-input package "openmpi")
(lookup-package-input package "mpich")
Description: This is a digitally signed message part
[bug#49597] [PATCH core-updates 00/15] Ajust packages to label-less input style, Mathieu Othacehe, 2021/07/17
[bug#49597] [PATCH core-updates 00/15] Ajust packages to label-less input style, Maxime Devos, 2021/07/18
bug#49597: [PATCH core-updates 00/15] Ajust packages to label-less input style, Ludovic Courtès, 2021/07/24