Prepare to reduce code repetition in mh-edit

src/bin/mh-edit.rs

@@ -1,16 +1,14 @@
-use std::fs::OpenOptions;
 use std::path::PathBuf;
 use structopt::StructOpt;
 
 use musichoard::{
-    database::{
-        json::{backend::JsonDatabaseFileBackend, JsonDatabase},
-        IDatabase,
-    },
+    database::json::{backend::JsonDatabaseFileBackend, JsonDatabase},
     library::NoLibrary,
-    Artist, ArtistId, ArtistProperties, MusicHoard,
+    ArtistId, MusicHoard,
 };
 
+type MH = MusicHoard<NoLibrary, JsonDatabase<JsonDatabaseFileBackend>>;
+
 #[derive(StructOpt, Debug)]
 struct Opt {
     #[structopt(subcommand)]
@@ -29,6 +27,14 @@ enum Category {
     Artist(ArtistCommand),
 }
 
+impl Category {
+    fn handle(self, music_hoard: &mut MH) {
+        match self {
+            Category::Artist(artist_command) => artist_command.handle(music_hoard),
+        }
+    }
+}
+
 #[derive(StructOpt, Debug)]
 enum ArtistCommand {
     New(ArtistValue),
@@ -66,22 +72,32 @@ struct MultiUrlValue {
     urls: Vec<String>,
 }
 
-fn main() {
-    let opt = Opt::from_args();
+macro_rules! url_command_dispatch {
+    ($command:ident, $mh:ident, $add:ident, $remove:ident, $set:ident, $clear:ident) => {
+        match $command {
+            UrlCommand::Add(single_url_value) => {
+                $mh.$add(ArtistId::new(single_url_value.artist), single_url_value.url)
+                    .expect("failed to add URL(s)");
+            }
+            UrlCommand::Remove(single_url_value) => {
+                $mh.$remove(ArtistId::new(single_url_value.artist), single_url_value.url)
+                    .expect("failed to remove URL(s)");
+            }
+            UrlCommand::Set(single_url_value) => {
+                $mh.$set(ArtistId::new(single_url_value.artist), single_url_value.url)
+                    .expect("failed to set URL(s)");
+            }
+            UrlCommand::Clear(artist_value) => {
+                $mh.$clear(ArtistId::new(artist_value.artist))
+                    .expect("failed to clear URL(s)");
+            }
+        }
+    };
+}
 
-    let lib: Option<NoLibrary> = None;
-    let db = Some(JsonDatabase::new(JsonDatabaseFileBackend::new(
-        &opt.database_file_path,
-    )));
-
-    let mut music_hoard = MusicHoard::new(lib, db);
-    music_hoard
-        .load_from_database()
-        .expect("failed to load database");
-
-    match opt.category {
-        Category::Artist(artist_command) => {
-            match artist_command {
+impl ArtistCommand {
+    fn handle(self, music_hoard: &mut MH) {
+        match self {
             ArtistCommand::New(artist_value) => {
                 music_hoard
                     .new_artist(ArtistId::new(artist_value.artist))
@@ -92,37 +108,14 @@ fn main() {
                     .delete_artist(ArtistId::new(artist_value.artist))
                     .expect("failed to delete artist");
             }
-                ArtistCommand::MusicBrainz(url_command) => match url_command {
-                    UrlCommand::Add(single_url_value) => {
-                        music_hoard
-                            .add_musicbrainz_url(
-                                ArtistId::new(single_url_value.artist),
-                                single_url_value.url,
-                            )
-                            .expect("failed to add MusicBrainz URL");
-                    }
-                    UrlCommand::Remove(single_url_value) => {
-                        music_hoard
-                            .remove_musicbrainz_url(
-                                ArtistId::new(single_url_value.artist),
-                                single_url_value.url,
-                            )
-                            .expect("failed to remove MusicBrainz URL");
-                    }
-                    UrlCommand::Set(single_url_value) => {
-                        music_hoard
-                            .set_musicbrainz_url(
-                                ArtistId::new(single_url_value.artist),
-                                single_url_value.url,
-                            )
-                            .expect("failed to set MusicBrainz URL");
-                    }
-                    UrlCommand::Clear(artist_value) => {
-                        music_hoard
-                            .clear_musicbrainz_url(ArtistId::new(artist_value.artist))
-                            .expect("failed to clear MusicBrainz URL");
-                    }
-                },
+            ArtistCommand::MusicBrainz(url_command) => url_command_dispatch!(
+                url_command,
+                music_hoard,
+                add_musicbrainz_url,
+                remove_musicbrainz_url,
+                set_musicbrainz_url,
+                clear_musicbrainz_url
+            ),
             ArtistCommand::MusicButler(url_command) => {
                 match url_command {
                     UrlCommand::Add(_) => {
@@ -173,7 +166,22 @@ fn main() {
             }
         }
     }
-    }
+}
+
+fn main() {
+    let opt = Opt::from_args();
+
+    let lib: Option<NoLibrary> = None;
+    let db = Some(JsonDatabase::new(JsonDatabaseFileBackend::new(
+        &opt.database_file_path,
+    )));
+
+    let mut music_hoard = MusicHoard::new(lib, db);
+    music_hoard
+        .load_from_database()
+        .expect("failed to load database");
+
+    opt.category.handle(&mut music_hoard);
 
     music_hoard
         .save_to_database()

src/lib.rs

@@ -279,6 +279,12 @@ pub struct ArtistId {
     pub name: String,
 }
 
+impl AsRef<ArtistId> for ArtistId {
+    fn as_ref(&self) -> &ArtistId {
+        self
+    }
+}
+
 impl ArtistId {
     pub fn new<S: Into<String>>(name: S) -> ArtistId {
         ArtistId { name: name.into() }