diff --git a/lib/referator/machine.rb b/lib/referator/machine.rb
index 6f2dde1..3c8b3f1 100644
--- a/lib/referator/machine.rb
+++ b/lib/referator/machine.rb
@@ -12,60 +12,10 @@ module Referator
     end
 
     def call(command)
-      case command.name
-      ##################
-      # Administrative #
-      ##################
-      when :exit
-        exit
-      when :ping
-        :pong
-      ##########
-      # Config #
-      ##########
-      when :register_script
-        @config.scripts.register(**command.data.transform_keys(&:to_sym))
-        nil
-      when :register_category
-        @config.categories.register command.data
-        nil
-      when :register_format
-        @config.formats.register(**command.data.transform_keys(&:to_sym))
-        nil
-      when :register_ref
-        @config.repo.register_ref(**command.data.transform_keys(&:to_sym))
-        nil
-      ########
-      # Info #
-      ########
-      when :ref
-        @config.freeze
-        @config.repo[command.data['category'], command.data['id']].to_h
-      ############
-      # Creation #
-      ############
-      when :make_ref
-        @config.freeze
-        @footnotes.make_ref(command.data['category'], command.data['id']).to_h
-      #############
-      # Rendering #
-      #############
-      when :fetch_footnotes
-        @config.freeze
-        @footnotes.fetch_footnotes
-      when :fetch_note
-        @config.freeze
-        @footnotes.fetch_note(command.data['category'], command.data['id']).to_h
-      when :render_footnotes
-        @config.freeze
-        String @footnotes.render_footnotes command.data
-      when :render_cite_sup
-        @config.freeze
-        String \
-          @footnotes.render_cite_sup(**command.data.transform_keys(&:to_sym))
-      else
-        raise 'Invalid command'
-      end
+      method_name = "do_#{command.name}"
+      raise 'Invalid command' unless respond_to? method_name, true
+
+      send method_name, command
     end
 
   private
@@ -77,5 +27,83 @@ module Referator
 
       @workdir = workdir
     end
+
+    ##################
+    # Administrative #
+    ##################
+
+    def do_exit(_command)
+      exit
+    end
+
+    def do_ping(_command)
+      :pong
+    end
+
+    ##########
+    # Config #
+    ##########
+
+    def do_register_script(command)
+      @config.scripts.register(**command.data.transform_keys(&:to_sym))
+      nil
+    end
+
+    def do_register_category(command)
+      @config.categories.register command.data
+      nil
+    end
+
+    def do_register_format(command)
+      @config.formats.register(**command.data.transform_keys(&:to_sym))
+      nil
+    end
+
+    def do_register_ref(command)
+      @config.repo.register_ref(**command.data.transform_keys(&:to_sym))
+      nil
+    end
+
+    ########
+    # Info #
+    ########
+
+    def do_ref(command)
+      @config.freeze
+      @config.repo[command.data['category'], command.data['id']].to_h
+    end
+
+    ############
+    # Creation #
+    ############
+
+    def do_make_ref(command)
+      @config.freeze
+      @footnotes.make_ref(command.data['category'], command.data['id']).to_h
+    end
+
+    #############
+    # Rendering #
+    #############
+
+    def do_fetch_footnotes(_command)
+      @config.freeze
+      @footnotes.fetch_footnotes
+    end
+
+    def do_fetch_note(command)
+      @config.freeze
+      @footnotes.fetch_note(command.data['category'], command.data['id']).to_h
+    end
+
+    def do_render_footnotes(command)
+      @config.freeze
+      String @footnotes.render_footnotes command.data
+    end
+
+    def do_render_cite_sup(command)
+      @config.freeze
+      String @footnotes.render_cite_sup(**command.data.transform_keys(&:to_sym))
+    end
   end
 end