more random Perl6::Documentable::Registry hackery

Author: moritz

lib/Perl6/Documentable/Registry.pm

@@ -2,9 +2,28 @@ use v6;
 use Perl6::Documentable;
 
 class Perl6::Documentable::Registry {
-    has @!documentables;
+    has @.documentables;
+    has Bool $.composed = False;
+    has %!cache;
+    has %!grouped-by
     method add-new(*%args) {
+        die "Cannot add something to a composed registry" if $.composed;
         @!documentables.push: Perl6::Documentable.new(|%args);
         1;
     }
+    method compose() {
+        $!composed = True;
+    }
+    method grouped-by(Str $what) {
+        die "You need to compose this registry first" unless $.composed;
+        %!grouped-by ||= @!documentables.classify(*."$what"());
+    }
+    method lookup(Str $what, Str :$by!) {
+        unless %!cache.exists($by) {
+            for @!documentables -> $d {
+                %!cache{$by}{$d."$by"()}.push: $d;
+            }
+        }
+        %!cache{$by}{$d};
+    }
 }