services: replace bare serializers with (serializer ...)

* gnu/home/services/shells.scm
(home-zsh-configuration)[environment-variables]: Use (serializer ...).
(home-bash-configuration)[aliases, environment-variables]: Likewise.
(home-fish-configuration)[abbreviations, aliases]
[environment-variables]: Likewise.
* gnu/services/audio.scm (mpd-configuration)[music-dir, playlist-dir]
[endpoints, address, inputs, archive-plugins, input-cache-size]
[decoders, filters, playlist-plugins]: Likewise.
* gnu/services/linux.scm (fstrim-configuration)[extra-arguments]:
Likewise.
* gnu/services/security.scm (fail2ban-jail-configuration)[backend]
[log-encoding, extra-content]: Likewise.
* tests/services/configuration.scm: Update tests.
("serialize-configuration [deprecated]"): New test.

Signed-off-by: Liliana Marie Prikler <liliana.prikler@gmail.com>

4 files changed, 36 insertions, 34 deletions

diff --git a/gnu/home/services/shells.scm b/gnu/home/services/shells.scm
index 3326eb37f4..f05f2221d6 100644
--- a/gnu/home/services/shells.scm
+++ b/gnu/home/services/shells.scm
@@ -133,7 +133,7 @@ Shell startup process will continue with
   (environment-variables
    (alist '())
    "Association list of environment variables to set for the Zsh session."
-   serialize-posix-env-vars)
+   (serializer serialize-posix-env-vars))
   (zshenv
    (text-config '())
    "List of file-like objects, which will be added to @file{.zshenv}.
@@ -334,7 +334,7 @@ source ~/.profile
 rules for the @code{home-environment-variables-service-type} apply
 here (@pxref{Essential Home Services}).  The contents of this field will be
 added after the contents of the @code{bash-profile} field."
-   serialize-posix-env-vars)
+   (serializer serialize-posix-env-vars))
   (aliases
    (alist '())
    "Association list of aliases to set for the Bash session.  The aliases will be
@@ -351,7 +351,7 @@ turns into
 @example
 alias ls=\"ls -alF\"
 @end example"
-   bash-serialize-aliases)
+   (serializer bash-serialize-aliases))
   (bash-profile
    (text-config '())
    "List of file-like objects, which will be added to @file{.bash_profile}.
@@ -536,19 +536,19 @@ with text blocks from other extensions and the base service."))
   (environment-variables
    (alist '())
    "Association list of environment variables to set in Fish."
-   serialize-fish-env-vars)
+   (serializer serialize-fish-env-vars))
   (aliases
    (alist '())
    "Association list of aliases for Fish, both the key and the value
 should be a string.  An alias is just a simple function that wraps a
 command, If you want something more akin to @dfn{aliases} in POSIX
 shells, see the @code{abbreviations} field."
-   serialize-fish-aliases)
+   (serializer serialize-fish-aliases))
   (abbreviations
    (alist '())
    "Association list of abbreviations for Fish.  These are words that,
 when typed in the shell, will automatically expand to the full text."
-   serialize-fish-abbreviations))
+   (serializer serialize-fish-abbreviations)))
 
 (define (fish-files-service config)
   `(("fish/config.fish"
diff --git a/gnu/services/audio.scm b/gnu/services/audio.scm
index 4885fb8424..c073b85a32 100644
--- a/gnu/services/audio.scm
+++ b/gnu/services/audio.scm
@@ -370,7 +370,7 @@ Available values: @code{notice}, @code{info}, @code{verbose},
   (music-dir ; TODO: deprecated, remove later
    maybe-string
    "The directory to scan for music files."
-   mpd-serialize-deprecated-field)
+   (serializer mpd-serialize-deprecated-field))
 
   (playlist-directory
    maybe-string
@@ -379,7 +379,7 @@ Available values: @code{notice}, @code{info}, @code{verbose},
   (playlist-dir ; TODO: deprecated, remove later
    maybe-string
    "The directory to store playlists."
-   mpd-serialize-deprecated-field)
+   (serializer mpd-serialize-deprecated-field))
 
   (db-file
    maybe-string
@@ -405,16 +405,17 @@ IPv6 addresses must be enclosed in square brackets when a different
 port is used.
 To use a Unix domain socket, an absolute path or a path starting with @code{~}
 can be specified here."
-   (lambda (_ endpoints)
-     (if (maybe-value-set? endpoints)
-         (mpd-serialize-list-of-strings "bind_to_address" endpoints)
-         "")))
+   (serializer
+    (lambda (_ endpoints)
+      (if (maybe-value-set? endpoints)
+          (mpd-serialize-list-of-strings "bind_to_address" endpoints)
+          ""))))
 
   (address ; TODO: deprecated, remove later
    maybe-string
    "The address that mpd will bind to.
 To use a Unix domain socket, an absolute path can be specified here."
-   mpd-serialize-deprecated-field)
+   (serializer mpd-serialize-deprecated-field))
 
   (database
    maybe-mpd-plugin
@@ -431,29 +432,29 @@ To use a Unix domain socket, an absolute path can be specified here."
   (inputs
    (list-of-mpd-plugin '())
    "List of MPD input plugin configurations."
-   (lambda (_ x)
-     (mpd-serialize-list-of-mpd-plugin "input" x)))
+   (serializer (lambda (_ x)
+                 (mpd-serialize-list-of-mpd-plugin "input" x))))
 
   (archive-plugins
    (list-of-mpd-plugin '())
    "List of MPD archive plugin configurations."
-   (lambda (_ x)
-     (mpd-serialize-list-of-mpd-plugin "archive_plugin" x)))
+   (serializer (lambda (_ x)
+                 (mpd-serialize-list-of-mpd-plugin "archive_plugin" x))))
 
   (input-cache-size
    maybe-string
    "MPD input cache size."
-   (lambda (_ x)
-     (if (maybe-value-set? x)
-         #~(string-append "\ninput_cache {\n"
-                          #$(mpd-serialize-string "size" x)
-                          "}\n") "")))
+   (serializer (lambda (_ x)
+                 (if (maybe-value-set? x)
+                     #~(string-append "\ninput_cache {\n"
+                                      #$(mpd-serialize-string "size" x)
+                                      "}\n") ""))))
 
   (decoders
    (list-of-mpd-plugin '())
    "List of MPD decoder plugin configurations."
-   (lambda (_ x)
-     (mpd-serialize-list-of-mpd-plugin "decoder" x)))
+   (serializer (lambda (_ x)
+                 (mpd-serialize-list-of-mpd-plugin "decoder" x))))
 
   (resampler
    maybe-mpd-plugin
@@ -462,8 +463,8 @@ To use a Unix domain socket, an absolute path can be specified here."
   (filters
    (list-of-mpd-plugin '())
    "List of MPD filter plugin configurations."
-   (lambda (_ x)
-     (mpd-serialize-list-of-mpd-plugin "filter" x)))
+   (serializer (lambda (_ x)
+                 (mpd-serialize-list-of-mpd-plugin "filter" x))))
 
   (outputs
    (list-of-mpd-plugin-or-output (list (mpd-output)))
@@ -473,8 +474,8 @@ By default this is a single output using pulseaudio.")
   (playlist-plugins
    (list-of-mpd-plugin '())
    "List of MPD playlist plugin configurations."
-   (lambda (_ x)
-     (mpd-serialize-list-of-mpd-plugin "playlist_plugin" x)))
+   (serializer (lambda (_ x)
+                 (mpd-serialize-list-of-mpd-plugin "playlist_plugin" x))))
 
   (extra-options
    (alist '())
diff --git a/gnu/services/linux.scm b/gnu/services/linux.scm
index 439848919d..4f28044112 100644
--- a/gnu/services/linux.scm
+++ b/gnu/services/linux.scm
@@ -213,9 +213,10 @@ option in fstab are skipped.")
    maybe-list-of-strings
    "Extra options to append to @command{fstrim} (run @samp{man fstrim} for
 more information)."
-   (lambda (_ value)
-     (if (maybe-value-set? value)
-         value '())))
+   (serializer
+    (lambda (_ value)
+      (if (maybe-value-set? value)
+          value '()))))
   (prefix fstrim-))
 
 (define (serialize-fstrim-configuration config)
diff --git a/gnu/services/security.scm b/gnu/services/security.scm
index 8116072920..e750bb468b 100644
--- a/gnu/services/security.scm
+++ b/gnu/services/security.scm
@@ -200,7 +200,7 @@
    "Backend to use to detect changes in the @code{log-path}.  The default is
 'auto.  To consult the defaults of the jail configuration, refer to the
 @file{/etc/fail2ban/jail.conf} file of the @code{fail2ban} package."
-   fail2ban-jail-configuration-serialize-backend)
+   (serializer fail2ban-jail-configuration-serialize-backend))
   (max-retry
    maybe-integer
    "The number of failures before a host get banned
@@ -269,7 +269,7 @@ names matching their filter name.")
    maybe-symbol
    "The encoding of the log files handled by the jail.
 Possible values are: @code{'ascii}, @code{'utf-8} and @code{'auto}."
-   fail2ban-jail-configuration-serialize-log-encoding)
+   (serializer fail2ban-jail-configuration-serialize-log-encoding))
   (log-path
    (list-of-strings '())
    "The file names of the log files to be monitored.")
@@ -280,7 +280,7 @@ Possible values are: @code{'ascii}, @code{'utf-8} and @code{'auto}."
    (text-config '())
    "Extra content for the jail configuration, provided as a list of file-like
 objects."
-   serialize-text-config)
+   (serializer serialize-text-config))
   (prefix fail2ban-jail-configuration-))
 
 (define list-of-fail2ban-jail-configurations?