From: "Ludovic Courtès" <ludo@gnu.org>
To: 39945@debbugs.gnu.org
Cc: "Ludovic Courtès" <ludo@gnu.org>
Subject: [bug#39945] [PATCH 0/1] Introducing 'with-parameters' for gexp dynamic binding
Date: Fri, 6 Mar 2020 11:41:08 +0100 [thread overview]
Message-ID: <20200306104108.19503-1-ludo@gnu.org> (raw)
Hello Guix!
This patch adds a new ‘with-parameters’ form. It is like ‘parameterize’
except that it takes effect when a file-like object is lowered, as in:
;; Return coreutils for i686.
(with-parameters ((%current-system "i686-linux"))
coreutils)
‘with-parameters’ is necessary because if you would use ‘parameterize’
in the example above, it wouldn’t have any effect at all: the dynamic
binding would be installed at the wrong time.
It works for any SRFI-39 parameter, though ‘%current-system’ is my main
use case. It makes it possible to have gexps or manifests that include
things explicitly targeting a given system. (For instance, I’d like to
have a manifest for release-critical things that explicitly pins the
targeted systems.)
Note that ‘with-parameters’ applies to file-like objects; it is _not_ a
property of the gexp itself. So one cannot, for example, write:
(with-parameters ((%current-system "i686-linux"))
#~(a b c d))
I feel like it’s better this way, though it could be confusing.
Thoughts?
Besides, ‘with-parameters’ is the dual of what was discussed at
<https://issues.guix.gnu.org/issue/29296>.
Thanks,
Ludo’.
Ludovic Courtès (1):
gexp: Add 'with-parameters'.
.dir-locals.el | 1 +
doc/guix.texi | 19 ++++++++++++++++
guix/gexp.scm | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++
tests/gexp.scm | 28 ++++++++++++++++++++++++
4 files changed, 107 insertions(+)
--
2.25.1
next reply other threads:[~2020-03-06 10:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-06 10:41 Ludovic Courtès [this message]
2020-03-06 10:53 ` [bug#39945] [PATCH 1/1] gexp: Add 'with-parameters' Ludovic Courtès
2020-03-06 11:06 ` [bug#39945] [PATCH 0/1] Introducing 'with-parameters' for gexp dynamic binding Mathieu Othacehe
2020-03-12 17:34 ` bug#39945: " Ludovic Courtès
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