[bug#63320] [PATCH 0/2] Rewrite 'arguments' to gexps with 'guix style -S arguments'

[Ludovic Courtès]

Hello Guix!

When preparing <https://guix.gnu.org/en/blog/2021/the-big-change/>, I didn’t
consider converting ‘arguments’ from sexps to gexps a priority.  In practice,
we’ve been doing that manually ever since but there’s a sort of a 
“contamination”
aspect: due to inheritance, we often have to be careful enough to convert
multiple packages at once or to not change anything, or we end up with gexp
records inside sexps¹.  Automation appears to be overdue.

The attached patches add ‘guix style -S arguments’, which rewrites ‘arguments’
from sexps to gexps.  The change doesn’t involve any rebuild, so we could even
run it en masse on the whole repo and be done with it.

Some caveats:

  • The reader in (guix read-print) doesn’t support sexp comments (#;), which
    are used in a couple of packages.  Thus,

      ./pre-inst-env guix style -S arguments

    which traverses all the packages eventually chokes on it.

  • The pretty printer does not insert a newline after #:phases, which makes
    the space for (modify-phases …) expressions sometimes too narrow.  (This
    is not new; try ‘./pre-inst-env guix style PACKAGE’.)

  • More generally, the pretty printer’s output still has occasional glitches,
    sufficiently that running ‘guix style -S arguments’ on the whole repo may
    not be a good idea at the moment.

  • Some modules lack #:use-module (guix gexp), but this has to be added
    manually.

  • We might want an optional conservative policy to leave arguments that
    would not use gexps unchanged.  For instance, we could leave
    (arguments '(#:tests? #f)) unchanged instead of rewriting it to
    (arguments (list #:tests? #f)).

Thoughts?

Ludo’.

¹ This is what prompted Chris to improve error detection:
  <https://issues.guix.gnu.org/63263>.


Ludovic Courtès (2):
  style: Add 'arguments' styling rule.
  DRAFT news: Add entry to 'guix style -S arguments'.

 doc/guix.texi          |  51 ++++++++++++
 etc/news.scm           |  16 ++++
 guix/scripts/style.scm | 173 ++++++++++++++++++++++++++++++++++++++++-
 tests/style.scm        | 136 ++++++++++++++++++++++++++++++++
 4 files changed, 375 insertions(+), 1 deletion(-)


base-commit: 3c91f4ca490a7ac56dc0aebbca9c4bf4df201877
-- 
2.39.2