Last-Modified: 2023-03-27T17:30:28+01:00


SPDX-License-Identifier: CC0-1.0
SPDX-FileCopyrightText: 2023 Bruno Victal


                                 Guix Development Cheats


Miscellaneous collection of tricks.


Crappy cheats for the Emacs+Geiser illiterate
===========================================================================================


# Generating documentation for a define-configuration

"""Guix REPL"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
scheme@(guix-user)> ,m (gnu services <THE MODULE CONTAINING YOUR SERVICE>)
scheme@(guix-user)> (with-output-to-file "/tmp/generated-doc.txt" (lambda () (configuration->documentation 'my-service-configuration)))
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""


G-Expression bestiary
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# Handling quoted lists (such as mcron time expressions)

To “paste” a quoted list into a G-Expression:
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
#~'(#$@variable)
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

I should mention that the following snippet does not work:
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
#$(if (list? schedule) `(list ,@schedule) schedule)

;; If schedule is defined as
;;
;;     '(next-second (range 0 60 30))
;;
;; then this is going to be ungexp'd as
;;
;;     (list next-second (0 30))
;;
;; Notice how only the first layer survived the quoting process.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""


# Simple lists and procedures returning lists

Place a quote before #~(…). This applies to procedures returning lists as well.
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
#~(…
   '#$(map func (list …)))

#~(… '#$lst …)
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

This is due to the list being processed and “pasted” as (a b c …) inside the G-Expression,
which resembles a procedure call to `a' rather than a list.



Guix internals
===========================================================================================


# Get available system tests

"""GUIX repl"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
scheme@(guix-user)> ,use (guix profiles)
scheme@(guix-user)> ,pp (map manifest-entry-name (manifest-entries (load "etc/system-tests.scm")))
Selected 114 system tests...
$1 = ("test.mympd"       
 "test.mpd"     
 "test.linux-libre-4.14"
 "test.basic"
⋮
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""