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[bug#44321] [PATCH 6/6] doc: Add "Defining Package Variants" section.
From: |
zimoun |
Subject: |
[bug#44321] [PATCH 6/6] doc: Add "Defining Package Variants" section. |
Date: |
Fri, 30 Oct 2020 12:20:18 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) |
Hi,
On Fri, 30 Oct 2020 at 00:10, Ludovic Courtès <ludo@gnu.org> wrote:
> -* Invoking guix repl:: Programming Guix in Guile.
> +* Invoking guix repl:: Programming Guix in Guile
This change is already in commit 729d4ba025bc8556d00041f9af5b6609eeec9d80.
> +You can just as well define variants with a different set of
> +dependencies than the original package. For example, the default
> +@code{gdb} package depends on @code{guile}, but since that is an
> +optional dependency, you can define a variant that removes that
> +dependency like so:
> +
> +@lisp
> +(use-modules (gnu packages gdb) ;for 'gdb'
> + (srfi srfi-1)) ;for 'alist-delete'
> +
> +(define gdb-sans-guile
> + (package
> + (inherit gdb)
> + (inputs (alist-delete "guile"
> + (package-inputs gdb)))))
> +@end lisp
Does it make sense to add a sentence explaining that the “guile” is the
name provided by the string in the ’inputs’ list of the package ’gdb’,
namely:
--8<---------------cut here---------------start------------->8---
(inputs
`(("expat" ,expat)
("mpfr" ,mpfr)
("gmp" ,gmp)
("readline" ,readline)
("ncurses" ,ncurses)
("guile" ,guile-2.0)
("python-wrapper" ,python-wrapper)
("source-highlight" ,source-highlight)
;; Allow use of XML-formatted syscall information. This enables 'catch
;; syscall' and similar commands.
("libxml2" ,libxml2)
;; The Hurd needs -lshouldbeinlibc.
,@(if (hurd-target?) `(("hurd" ,hurd)) '())))
--8<---------------cut here---------------end--------------->8---
? Because it can be confusing. Especially when the ’rewriting’ works
on symbols instead.
> +@deffn {Scheme Procedure} options->transformation @var{opts}
> +Return a procedure that, when passed an object to build (package,
> +derivation, etc.), applies the transformations specified by @var{opts} and
> returns
> +the resulting objects. @var{opts} must be a list of symbol/string pairs
> such as:
> +
> +@example
> +((with-branch . "guile-gcrypt=master")
> + (without-tests . "libgcrypt"))
> +@end example
Is it on purpose that here you use ’without-tests’ and then…
> +Each symbol names a transformation and the corresponding string is an
> argument
> +to that transformation.
> +@end deffn
> +
> +For instance, a manifest equivalent to this command:
> +
> +@example
> +guix build guix \
> + --with-branch=guile-gcrypt=master \
> + --with-debug-info=zlib
> +@end example
> +
> +@noindent
> +... would look like this:
> +
> +@lisp
> +(use-modules (guix transformations))
> +
> +(define transform
> + ;; The package transformation procedure.
> + (options->transformation
> + '((with-branch . "guile-gcrypt=master")
> + (with-debug-info . "zlib"))))
> +
> +(packages->manifest
> + (list (transform (specification->package "guix"))))
> +@end lisp
…you use ’with-debug-info’ as example?
> +@lisp
> +(define libressl-instead-of-openssl
> + ;; Replace all the packages called "openssl" with LibreSSL.
> + (package-input-rewriting/spec `(("openssl" . ,(const libressl)))))
> +@end lisp
It is already in the manual but why this ’const’?
BTW, cool! Nice features! :-)
All the best,
simon
[bug#44321] [PATCH 4/6] guix build: Move transformation options to (guix transformations)., Ludovic Courtès, 2020/10/29
[bug#44321] [PATCH 1/6] guix build: 'package-with-source' no longer takes a 'store' parameter., Miguel Ángel Arruga Vivas, 2020/10/30