Add palceholder post and update db init

blog

@@ -2,6 +2,7 @@
 use v6.e.PREVIEW;
 
 use DB;
+use DB::BlogMeta;
 use DB::MarkdownPost;
 
 my %*SUB-MAIN-OPTS =
@@ -45,9 +46,9 @@ multi MAIN(
     print "Tagline: ";
     my $tagline = get;
 
-    my $meta = DB::BlogMeta.new: title => $title, tagline => $tagline;
+    my $meta = BlogMeta.new: title => $title, tagline => $tagline;
 
-    my $db = DB::PostDB.new: meta => $meta;
+    my $db = DB::PostDB.init: $meta;
 
     if $force {
         $db-file.spurt: $db.to-json, :create-only;

lib/DB.rakumod

@@ -10,10 +10,17 @@ use DB::Post;
 use DB::BlogMeta;
 use DB::MarkdownPost;
 use DB::IdrisPost;
+use DB::PlaceholderPost;
 
-class Posts is json(:dictionary(:keyof(Int:D), MarkdownPost:D, IdrisPost:D)) {}
+class Posts is json(
+    :dictionary()
+        :keyof(Int:D),
+        MarkdownPost:D,
+        IdrisPost:D,
+        PlaceholderPost:D,
+    )) {}
 
-subset PostTypes where MarkdownPost:D | IdrisPost:D;
+subset PostTypes where MarkdownPost:D | IdrisPost:D | PlaceholderPost:D;
 
 #| The top level posts database
 class PostDB is json(:pretty) {
@@ -21,6 +28,8 @@ class PostDB is json(:pretty) {
    has BlogMeta:D $.meta is required;
    #| A mapping from post ids to posts
    has %.posts is Posts;
+   #| The post id to use for placeholder posts
+   has Int $.placeholder-id = 0;
 
    method TWEAK() {
        %!posts := Posts.new unless %!posts;
@@ -41,4 +50,14 @@ class PostDB is json(:pretty) {
        %!posts{$id} = $post;
        $id
    }
+
+   #| Initialize a new database
+   method init(BlogMeta:D $meta --> PostDB:D) {
+       my %posts is Posts = Posts.new;
+       %posts{0} = PlaceholderPost.empty;
+       PostDB.new(
+           meta => $meta,
+           posts => %posts,
+       )
+   }
 }

lib/DB/PlaceholderPost.rakumod

@@ -0,0 +1,32 @@
+use v6.e.PREVIEW
+
+use Pandoc;
+use JSON::Class:auth<zef:vrurg>;
+
+use DB::Post;
+
+#| An empty placeholder post
+unit class PlaceholderPost does Post is json;
+
+#| Marker for disambiguation between post types in json representation, the
+#| cheaty way
+has Bool:D $.placeholder = True;
+
+method title(--> Str:D) {
+    "Placeholder Article"
+}
+
+#| Shortcut for creating an empty placeholder post
+method empty(--> PlaceholderPost:D) {
+    PlaceholderPost.new(
+        source => "/dev/null".IO,
+        posted-at => DateTime.now,
+        hidden => True,
+    )
+}
+
+# Override the all-slugs method to return an empty array, we don't want the
+# placeholder article to be refered to as anything but its id
+method all-slugs(--> Array[Str:D]) {
+    Array[Str:D].new
+}