From: ludo@gnu.org (Ludovic Courtès)
To: Andreas Enge <andreas@enge.fr>
Cc: guix-devel@gnu.org
Subject: Re: Naming scheme for Python packages
Date: Sat, 07 Sep 2013 14:49:07 +0200 [thread overview]
Message-ID: <877ges94qk.fsf@gnu.org> (raw)
In-Reply-To: <20130906215311.GB15258@debian> (Andreas Enge's message of "Fri, 6 Sep 2013 23:53:11 +0200")
Andreas Enge <andreas@enge.fr> skribis:
> On Thu, Sep 05, 2013 at 03:00:27PM +0200, Ludovic Courtès wrote:
>> BTW, I haven’t check whether this is the case already, but we need
>> something like
>> (define (package-with-explicit-python p python)
>> ;; Return a version of P built for PYTHON.
>> (package (inherit p) ...))
>> so we can just write:
>> (define python2-pytz
>> (package-with-explicit-python python-pytz python-2))
>
> The attached patch does almost this, following our offline discussion on
> how to create packages recursively on the fly:
> - It adds an argument pair "#:python ,python-2", or replaces an already
> present argument "#:python something-else", and this recursively
> for all inputs and native-inputs that use the python build system.
> - It rewrites the corresponding names from "python-..." to "python2-...",
> or adds a prefix "python2-".
Great!
> So one can write
> (define python2-pytz
> (package-with-explicit-python python-pytz))
> As the second argument would always be python-2, I decided to drop it.
Still it’s better to keep it, as a generic version. Then, we can have:
(define package-with-python-2
(cut package-with-explicit-python <> python-2))
and then use that as needed.
> +(define-public (package-with-python2 p)
> + "Create a package with the same fields as P, which is assumed to use
> +PYTHON-BUILD-SYSTEM and to be compiled with the default python, such that
> +it is compiled with python 2 instead. The name of P is prefixed with
> +\"python2-\"; a potential existing prefix \"python-\" is dropped."
> + (let ((rewrite (lambda (x)
> + ;; procedure taking a two-element list ("name" package)
> + ;; and returning a two element list
> + ;; ("name" (package-with-python2 package))
> + (let ((name (car x))
> + (content (car (cdr x))))
> + (list name
> + (if (package? content)
> + (package-with-python2 content)
> + content)))))
> + (build-system (package-build-system p)))
Sylistic note: never use ‘car’, ‘cdr’, and co; use ‘match’ instead: it
leads to code that is both more readable and more robust (info "(guile)
Pattern Matching"). In that case, you can even use ‘match-lambda’,
which is equivalent to:
(lambda (x)
(match x
...))
Second remark: inputs are actually tuples of one of two forms:
(name package)
(name package output)
The first form means that we take the default output of PACKAGE; the
second form specifies that we want OUTPUT of PACKAGE. This makes a
different for multiple-output packages, such as ‘libtool’ (info "(guix)
Packages with Multiple Outputs").
So the ‘rewrite’ procedure must look like this:
(define rewrite
(match-lambda
((name package)
...)
((name package output)
...)))
> + (package (inherit p)
> + (name
> + (let ((name (package-name p)))
> + (if (eq? build-system python-build-system)
> + (string-append "python2-"
> + (if (string-prefix? "python-" name)
> + (substring name 7)
> + name))
> + name)))
> + (arguments
> + (let ((arguments (package-arguments p))
> + (python2 (default-python2)))
> + (if (eq? build-system python-build-system)
> + (if (member #:python arguments)
> + (substitute-keyword-arguments arguments ((#:python p) python2))
> + (append arguments `(#:python ,python2)))
> + arguments)))
Please fix the indentation of the ‘if’ arms.
> + (inputs
> + (let ((inputs (package-inputs p)))
> + (if (null? inputs)
> + '()
> + (map rewrite inputs))))
(map rewrite (package-inputs p)) is enough; if (package-inputs p) is
null?, then that’ll return the empty list too.
> + (native-inputs
> + (let ((native-inputs (package-native-inputs p)))
> + (if (null? native-inputs)
> + '()
> + (map rewrite native-inputs)))))))
Ditto.
Thanks for working on this!
Ludo’.
next prev parent reply other threads:[~2013-09-07 12:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <E1VHJTB-0006ys-7X@vcs.savannah.gnu.org>
2013-09-04 20:51 ` Naming scheme for Python packages Ludovic Courtès
2013-09-04 20:52 ` Cyril Roelandt
2013-09-04 21:16 ` Andreas Enge
2013-09-04 21:07 ` Cyril Roelandt
2013-09-04 21:36 ` Andreas Enge
2013-09-04 21:08 ` Andreas Enge
2013-09-04 21:32 ` Andreas Enge
2013-09-05 13:00 ` Ludovic Courtès
2013-09-06 21:53 ` Andreas Enge
2013-09-07 12:49 ` Ludovic Courtès [this message]
2013-09-07 21:25 ` Andreas Enge
2013-09-08 14:03 ` Ludovic Courtès
2013-09-08 14:51 ` Andreas Enge
2013-09-08 20:00 ` Ludovic Courtès
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