yes|no => true|false

functions/bool_to_yesno.pp

+function mpd::bool_to_yesno (
+  Boolean $bool,
+) >> String {
+  if $bool { 'yes' } else { 'no' }
+}

manifests/server.pp

@@ -6,8 +6,8 @@ type Permission = Enum['read', 'add', 'control', 'admin']
 class mpd::server (
   String $music_directory,
   String $mpd_home = '/var/lib/mpd',
-  Boolean $follow_outside_symlinks = yes,
-  Boolean $follow_inside_symlinks = yes,
+  Boolean $follow_outside_symlinks = true,
+  Boolean $follow_inside_symlinks = true,
   String $db_file            = "${mpd_home}/database",
   String $sticker_file       = "${mpd_home}/sticker.sql",
   String $log_file           = "${mpd_home}/log",
@@ -18,7 +18,7 @@ class mpd::server (
   String $bind_to_address    = 'any',
   Integer $port              = 6600,
   Enum['default','secure','verbose'] $log_level = default,
-  Boolean $zeroconf_enabled = yes,
+  Boolean $zeroconf_enabled = true,
   Optional[String] $zeroconf_name,
   Optional[Array[Struct[{ name => String, permissions => Array[Permission]}]]] $password,
   Optional[Array[Permission]] $default_permissions,
@@ -32,13 +32,13 @@ class mpd::server (
   Optional[String] $filesystem_charset,
   Optional[String] $id3v1_encoding,
   Optional[Boolean] $gapless_mp3_playback,
-  Boolean $save_absolute_paths_in_playlists = no,
+  Boolean $save_absolute_paths_in_playlists = true,
   Optional[Variant[Enum['none'],
                   Array[Enum['artist', 'album', 'title',
                               'track', 'name', 'genre',
                               'date', 'composer', 'performer',
                               'comment', 'disc']]]] $metadata_to_use,
-  Boolean $auto_update = no,
+  Boolean $auto_update = true,
   Optional[Integer] $auto_update_depth,
 ) {
 
@@ -88,7 +88,13 @@ class mpd::server (
     target  => '/etc/mpd.conf',
     content => $hash
           .filter |$k, $v| { $v != undef }
-          .map |$k, $v| { "${k} \"${v}\"\n" }
+          .map |$k, $v| {
+            $val = $v ? {
+              Boolean => mpd::bool_to_yesno($v),
+              default => $v,
+            }
+            "${k} \"${val}\"\n"
+          }
           .join()
   }
 
@@ -103,7 +109,7 @@ class mpd::server (
         ensure   => present,
         baseurl  => 'https://download1.rpmfusion.org/free/el/updates/7/x86_64',
         enabled  => true,
-        gpgcheck => yes,
+        gpgcheck => true,
         gpgkey   => 'https://rpmfusion.org/keys?action=AttachFile&do=get&target=RPM-GPG-KEY-rpmfusion-free-el-7',
       }