From 85f8cd019dd275fb3ed0f4c0197d3a0c2d719e99 Mon Sep 17 00:00:00 2001
From: Kim Burgess <kim@acaprojects.com>
Date: Wed, 24 Oct 2018 23:53:58 +1000
Subject: [PATCH 1/8] (aca:rooms) initial component framework

---
 modules/aca/rooms/base.rb              | 23 +++++++
 modules/aca/rooms/collab.rb            | 26 ++++++++
 modules/aca/rooms/component_manager.rb | 87 ++++++++++++++++++++++++++
 modules/aca/rooms/components/io.rb     | 38 +++++++++++
 modules/aca/rooms/components/power.rb  | 11 ++++
 5 files changed, 185 insertions(+)
 create mode 100644 modules/aca/rooms/base.rb
 create mode 100644 modules/aca/rooms/collab.rb
 create mode 100644 modules/aca/rooms/component_manager.rb
 create mode 100644 modules/aca/rooms/components/io.rb
 create mode 100644 modules/aca/rooms/components/power.rb

diff --git a/modules/aca/rooms/base.rb b/modules/aca/rooms/base.rb
new file mode 100644
index 00000000..1661dd22
--- /dev/null
+++ b/modules/aca/rooms/base.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+load File.join(__dir__, 'component_manager.rb')
+
+module Aca; end
+module Aca::Rooms; end
+
+class Aca::Rooms::Base
+    include ::Orchestrator::Constants
+    include ::Aca::Rooms::ComponentManager
+
+    # ------------------------------
+    # Callbacks
+
+    def on_load
+        on_update
+    end
+
+    def on_update
+        self[:name] = system.name
+        self[:type] = self.class.name.demodulize
+    end
+end
diff --git a/modules/aca/rooms/collab.rb b/modules/aca/rooms/collab.rb
new file mode 100644
index 00000000..32ec1b5d
--- /dev/null
+++ b/modules/aca/rooms/collab.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'ostruct'
+
+::Orchestrator::DependencyManager.load('Aca::Rooms::Base', :logic)
+
+class Aca::Rooms::Collab < Aca::Rooms::Base
+    descriptive_name 'ACA Collaboration Space'
+    generic_name :System
+    implements :logic
+    description <<~DESC
+        Logic and external control API for collaboration spaces.
+
+        Collaboration spaces are rooms / systems where the design is centered
+        around a VC system, with the primary purpose of collaborating with both
+        people in room, as well as remote parties.
+    DESC
+
+    components :Power, :Io
+
+    def on_update
+        super
+        logger.debug "Methods are: #{self.methods}"
+        logger.debug ::Aca::Rooms::Base.new.methods
+    end
+end
diff --git a/modules/aca/rooms/component_manager.rb b/modules/aca/rooms/component_manager.rb
new file mode 100644
index 00000000..7b8a6365
--- /dev/null
+++ b/modules/aca/rooms/component_manager.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+module Aca; end
+module Aca::Rooms; end
+
+module Aca::Rooms::Components; end
+
+module Aca::Rooms::ComponentManager
+    module Composer
+        Hook = Struct.new :before, :during, :after
+
+        def compose_with(component, &extensions)
+            # Nested hash of { components => { method => Hook } }
+            const_set :HOOKS, {} unless const_defined? :HOOKS
+            hooks = const_get :HOOKS
+            hooks[component] ||= Hash.new { |h, k| h[k] = Hook.new }
+
+            # Mini-DSL for defining cross-component behaviours
+            composer = Class.new do
+                Hook.members.each do |position|
+                    define_method position do |method, &action|
+                        hooks[component][method][position] = action
+                    end
+                end
+            end
+
+            composer.new.instance_eval(&extensions)
+
+            self
+
+            # HOOKS = {
+            #     Power: {
+            #         powerup: ...
+            #     }
+            # }
+            #
+            # HOOKS = {
+            #     powerup: [...]
+            # }
+        end
+    end
+
+    module Mixin
+        def components(*components)
+            modules = components.map do |component|
+                fqn = "::Aca::Rooms::Components::#{component}"
+                ::Orchestrator::DependencyManager.load fqn, :logic
+            end
+
+            # Include the component methods
+            include(*modules)
+
+            # Get all cross-component behaviours for the loaded components
+            hooks = modules.select   { |mod| mod.singleton_class < Composer }
+                           .flat_map { |mod| mod::HOOKS.values_at(*components) }
+                           .compact
+
+            # Map [{ method => Hook }] to { method => [Hook] }
+            hooks = hooks.reduce { |a, b| a.merge(b) { |_, x, y| [*x, *y] } }
+                         .transform_values!          { |x| Array.wrap x }
+
+            overrides = Module.new do
+                hooks.each do |method, hook_list|
+                    define_method method do |*args|
+                        actions = [
+                            [hook_list.map(&:before)],
+                            [hook_list.map(&:during), -> { super }],
+                            [hook_list.map(&:after)]
+                        ]
+
+                        actions.reduce do
+
+                        end
+                    end
+                end
+            end
+
+            prepend overrides
+        end
+    end
+
+    module_function
+
+    def included(other)
+        other.extend Mixin
+    end
+end
diff --git a/modules/aca/rooms/components/io.rb b/modules/aca/rooms/components/io.rb
new file mode 100644
index 00000000..0dbca74c
--- /dev/null
+++ b/modules/aca/rooms/components/io.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+module Aca::Rooms::Components::Io
+    def show(source, on: default_outputs)
+        source = source.to_sym
+        target = Array(on).map(&:to_sym)
+
+        logger.debug "Showing #{source} on #{target.join ','}"
+
+        connect source => target
+    end
+
+    protected
+
+    def connect(signal_map)
+        logger.debug 'called connect'
+    end
+
+    def blank(outputs)
+        logger.debug 'called blank'
+    end
+
+    def default_outputs
+        []
+    end
+end
+
+Aca::Rooms::Components::Io.extend ::Aca::Rooms::ComponentManager::Composer
+
+Aca::Rooms::Components::Io.compose_with :Power do
+    during :powerup do
+        connect {} # config.default_routes
+    end
+
+    during :shutdown do
+        connect {}
+    end
+end
diff --git a/modules/aca/rooms/components/power.rb b/modules/aca/rooms/components/power.rb
new file mode 100644
index 00000000..49d63afe
--- /dev/null
+++ b/modules/aca/rooms/components/power.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Aca::Rooms::Components::Power
+    def powerup
+
+    end
+
+    def shutdown
+
+    end
+end

From 73a87d2d9abfb65ea0da4e6c0874c2d3455f7abd Mon Sep 17 00:00:00 2001
From: Kim Burgess <kim@acaprojects.com>
Date: Tue, 20 Nov 2018 17:50:17 +1000
Subject: [PATCH 2/8] (aca:rooms) refactor component composition

---
 modules/aca/rooms/component_manager.rb | 56 +++++++++++++-------------
 1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/modules/aca/rooms/component_manager.rb b/modules/aca/rooms/component_manager.rb
index 7b8a6365..61ca8da7 100644
--- a/modules/aca/rooms/component_manager.rb
+++ b/modules/aca/rooms/component_manager.rb
@@ -7,19 +7,18 @@ module Aca::Rooms::Components; end
 
 module Aca::Rooms::ComponentManager
     module Composer
-        Hook = Struct.new :before, :during, :after
+        Hook = Struct.new :method, :position, :action
 
         def compose_with(component, &extensions)
-            # Nested hash of { components => { method => Hook } }
+            # Hash of { component => [Hook] }
             const_set :HOOKS, {} unless const_defined? :HOOKS
-            hooks = const_get :HOOKS
-            hooks[component] ||= Hash.new { |h, k| h[k] = Hook.new }
+            hooks = const_get(:HOOKS)[component] = []
 
             # Mini-DSL for defining cross-component behaviours
             composer = Class.new do
-                Hook.members.each do |position|
+                [:before, :during, :after].each do |position|
                     define_method position do |method, &action|
-                        hooks[component][method][position] = action
+                        hooks << Hook.new(method, position, action)
                     end
                 end
             end
@@ -27,16 +26,6 @@ def compose_with(component, &extensions)
             composer.new.instance_eval(&extensions)
 
             self
-
-            # HOOKS = {
-            #     Power: {
-            #         powerup: ...
-            #     }
-            # }
-            #
-            # HOOKS = {
-            #     powerup: [...]
-            # }
         end
     end
 
@@ -54,22 +43,33 @@ def components(*components)
             hooks = modules.select   { |mod| mod.singleton_class < Composer }
                            .flat_map { |mod| mod::HOOKS.values_at(*components) }
                            .compact
+                           .flatten
 
-            # Map [{ method => Hook }] to { method => [Hook] }
-            hooks = hooks.reduce { |a, b| a.merge(b) { |_, x, y| [*x, *y] } }
-                         .transform_values!          { |x| Array.wrap x }
+            # Map from [Hook] to { method => { position => [action] } }
+            hooks = hooks.each_with_object({}) do |hook, h|
+                ((h[hook.method] ||= {})[hook.position] ||= []) << hook.action
+            end
 
             overrides = Module.new do
-                hooks.each do |method, hook_list|
+                hooks.each do |method, actions|
                     define_method method do |*args|
-                        actions = [
-                            [hook_list.map(&:before)],
-                            [hook_list.map(&:during), -> { super }],
-                            [hook_list.map(&:after)]
-                        ]
-
-                        actions.reduce do
-
+                        result = nil
+
+                        sequence = [
+                            actions[:before],
+                            [
+                                proc { result = super(*args) },
+                                *actions[:during]
+                            ],
+                            actions[:after]
+                        ].compact!
+
+                        sequence.reduce(thread.finally) do |prev, succ|
+                            prev.then do
+                                thread.all(succ.map { |x| instance_exec(*args, &x) })
+                            end
+                        end.then do
+                            result
                         end
                     end
                 end

From d186add4480bd919adcfe9e2c17bba644cc8e71b Mon Sep 17 00:00:00 2001
From: Kim Burgess <kim@acaprojects.com>
Date: Mon, 26 Nov 2018 01:15:22 +1000
Subject: [PATCH 3/8] (aca:rooms) fix component compositions stacking with
 every reload

---
 modules/aca/rooms/component_manager.rb | 98 +++++++++++++++-----------
 1 file changed, 56 insertions(+), 42 deletions(-)

diff --git a/modules/aca/rooms/component_manager.rb b/modules/aca/rooms/component_manager.rb
index 61ca8da7..5dbbd30d 100644
--- a/modules/aca/rooms/component_manager.rb
+++ b/modules/aca/rooms/component_manager.rb
@@ -7,75 +7,89 @@ module Aca::Rooms::Components; end
 
 module Aca::Rooms::ComponentManager
     module Composer
-        Hook = Struct.new :method, :position, :action
-
+        # Mini-DSL for defining cross-component behaviours.
+        #
+        # With the block provided `before`, `during`, or `after` can be used
+        # to insert additional behaviour to methods that should only exist when
+        # both components are in use. The result of the original method will
+        # be preserved, but will be deferred until the completion of any
+        # composite behaviours.
         def compose_with(component, &extensions)
-            # Hash of { component => [Hook] }
-            const_set :HOOKS, {} unless const_defined? :HOOKS
-            hooks = const_get(:HOOKS)[component] = []
+            # Build out a module heirachy so that <base>::Compositions::<other>
+            # exists and can be used to house any behaviour extensions to be
+            # applied when both components are in use.
+            overlay = [:Compositions, component].reduce(self) do |context, name|
+                if context.const_defined? name, false
+                    context.const_get name
+                else
+                    context.const_set name, Module.new
+                end
+            end
+
+            hooks = {}
 
-            # Mini-DSL for defining cross-component behaviours
+            # Eval the block to populate hooks with the overlay actions as
+            # method => { position => [actions] }
             composer = Class.new do
                 [:before, :during, :after].each do |position|
                     define_method position do |method, &action|
-                        hooks << Hook.new(method, position, action)
+                        ((hooks[method] ||= {})[position] ||= []) << action
                     end
                 end
             end
 
             composer.new.instance_eval(&extensions)
 
+            # Build the overlay Module for prepending
+            hooks.each do |method, actions|
+                # FIXME: this removes visibility of original args
+                overlay.send :define_method, method do |*args|
+                    result = nil
+
+                    sequence = [
+                        actions[:before],
+                        [
+                            proc { |*x| result = super(*x) },
+                            *actions[:during]
+                        ],
+                        actions[:after]
+                    ].compact!
+
+                    sequence.reduce(thread.finally) do |a, b|
+                        a.then do
+                            thread.all(b.map { |x| instance_exec(*args, &x) })
+                        end
+                    end.then do
+                        result
+                    end
+                end
+            end
+
             self
         end
     end
 
     module Mixin
         def components(*components)
+            # Load the associated module
             modules = components.map do |component|
                 fqn = "::Aca::Rooms::Components::#{component}"
                 ::Orchestrator::DependencyManager.load fqn, :logic
             end
 
-            # Include the component methods
+            # Include the component
             include(*modules)
 
-            # Get all cross-component behaviours for the loaded components
-            hooks = modules.select   { |mod| mod.singleton_class < Composer }
-                           .flat_map { |mod| mod::HOOKS.values_at(*components) }
-                           .compact
-                           .flatten
-
-            # Map from [Hook] to { method => { position => [action] } }
-            hooks = hooks.each_with_object({}) do |hook, h|
-                ((h[hook.method] ||= {})[hook.position] ||= []) << hook.action
-            end
+            # Compose cross-component behaviours
+            overlays = modules.flat_map do |base|
+                next unless base.const_defined? :Compositions, false
 
-            overrides = Module.new do
-                hooks.each do |method, actions|
-                    define_method method do |*args|
-                        result = nil
-
-                        sequence = [
-                            actions[:before],
-                            [
-                                proc { result = super(*args) },
-                                *actions[:during]
-                            ],
-                            actions[:after]
-                        ].compact!
-
-                        sequence.reduce(thread.finally) do |prev, succ|
-                            prev.then do
-                                thread.all(succ.map { |x| instance_exec(*args, &x) })
-                            end
-                        end.then do
-                            result
-                        end
-                    end
+                components.each_with_object([]) do |component, compositions|
+                    next unless base::Compositions.const_defined? component
+                    compositions << base::Compositions.const_get(component)
                 end
             end
-
-            prepend overrides
+            prepend(*overlays.compact)
         end
     end
 

From dbfb426b267bcb6826c52e3d78c3785f666f8132 Mon Sep 17 00:00:00 2001
From: Kim Burgess <kim@acaprojects.com>
Date: Mon, 26 Nov 2018 01:41:30 +1000
Subject: [PATCH 4/8] (aca:rooms) move construction of overlay modules to its
 own method

---
 modules/aca/rooms/component_manager.rb | 32 +++++++++++++++-----------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/modules/aca/rooms/component_manager.rb b/modules/aca/rooms/component_manager.rb
index 5dbbd30d..a7234eb2 100644
--- a/modules/aca/rooms/component_manager.rb
+++ b/modules/aca/rooms/component_manager.rb
@@ -15,16 +15,7 @@ module Composer
         # be preserved, but will be deferred until the completion of any
         # composite behaviours.
         def compose_with(component, &extensions)
-            # Build out a module heirachy so that <base>::Compositions::<other>
-            # exists and can be used to house any behaviour extensions to be
-            # applied when both components are in use.
-            overlay = [:Compositions, component].reduce(self) do |context, name|
-                if context.const_defined? name, false
-                    context.const_get name
-                else
-                    context.const_set name, Module.new
-                end
-            end
+            overlay = overlay_module_for component
 
             hooks = {}
 
@@ -55,18 +46,33 @@ def compose_with(component, &extensions)
                         actions[:after]
                     ].compact!
 
-                    sequence.reduce(thread.finally) do |a, b|
+                    exec_actions = sequence.reduce(thread.finally) do |a, b|
                         a.then do
                             thread.all(b.map { |x| instance_exec(*args, &x) })
                         end
-                    end.then do
-                        result
                     end
+
+                    exec_actions.then { result }
                 end
             end
 
             self
         end
+
+        private
+
+        # Build out a module heirachy so that <base>::Compositions::<other>
+        # exists and can be used to house any behaviour extensions to be
+        # applied when both components are in use.
+        def overlay_module_for(component)
+            [:Compositions, component].reduce(self) do |context, name|
+                if context.const_defined? name, false
+                    context.const_get name
+                else
+                    context.const_set name, Module.new
+                end
+            end
+        end
     end
 
     module Mixin

From 7b99ad5594a39a435e746e085519fec1d1d0a1ce Mon Sep 17 00:00:00 2001
From: Kim Burgess <kim@acaprojects.com>
Date: Fri, 30 Nov 2018 00:20:24 +1000
Subject: [PATCH 5/8] (aca:rooms) add support for defining component settings

---
 modules/aca/rooms/base.rb              | 17 ++++++++++
 modules/aca/rooms/component_manager.rb | 47 ++++++++++++++++++++++++--
 modules/aca/rooms/components/io.rb     |  2 ++
 modules/aca/rooms/components/power.rb  |  9 +++--
 4 files changed, 70 insertions(+), 5 deletions(-)

diff --git a/modules/aca/rooms/base.rb b/modules/aca/rooms/base.rb
index 1661dd22..70b2303c 100644
--- a/modules/aca/rooms/base.rb
+++ b/modules/aca/rooms/base.rb
@@ -9,6 +9,11 @@ class Aca::Rooms::Base
     include ::Orchestrator::Constants
     include ::Aca::Rooms::ComponentManager
 
+    def self.setting(hash)
+        previous = @default_settings || {}
+        default_settings previous.merge hash
+    end
+
     # ------------------------------
     # Callbacks
 
@@ -19,5 +24,17 @@ def on_load
     def on_update
         self[:name] = system.name
         self[:type] = self.class.name.demodulize
+
+        @config = Hash.new do |h, k|
+            h[k] = setting(k) || default_setting[k]
+        end
     end
+
+    protected
+
+    def default_setting
+        self.class.instance_variable_get :@default_settings
+    end
+
+    attr_reader :config
 end
diff --git a/modules/aca/rooms/component_manager.rb b/modules/aca/rooms/component_manager.rb
index a7234eb2..3c7f2b5d 100644
--- a/modules/aca/rooms/component_manager.rb
+++ b/modules/aca/rooms/component_manager.rb
@@ -77,13 +77,20 @@ def overlay_module_for(component)
 
     module Mixin
         def components(*components)
+            component_settings = {}
+
             # Load the associated module
             modules = components.map do |component|
-                fqn = "::Aca::Rooms::Components::#{component}"
-                ::Orchestrator::DependencyManager.load fqn, :logic
+                mod, settings = load component
+
+                component_settings.merge! settings do |key, _, _|
+                    raise "setting \"#{key}\" declared in multiple components"
+                end
+
+                mod
             end
 
-            # Include the component
+            # Include the components
             include(*modules)
 
             # Compose cross-component behaviours
@@ -96,6 +103,40 @@ def components(*components)
                 end
             end
             prepend(*overlays.compact)
+
+            # Bubble up settings definitions
+            setting component_settings
+        end
+
+        private
+
+        # Load a component, returning a reference to the Module and the
+        # settings it defines.
+        #
+        # Settings may be defined by using the 'setting' keyword within the
+        # component module. Support for this is temporarily mixed in during
+        # load below.
+        def load(component)
+            fqn = "::Aca::Rooms::Components::#{component}"
+
+            settings = {}
+
+            mod = if ::Aca::Rooms::Components.const_defined? component
+                      ::Aca::Rooms::Components.const_get component
+                  else
+                      ::Aca::Rooms::Components.const_set component, Module.new
+                  end
+
+            mod.define_singleton_method :setting do |hash|
+                settings.merge! hash do |key, _, _|
+                    raise "\"#{key}\" declared multiple times in #{fqn}"
+                end
+            end
+
+
+            ::Orchestrator::DependencyManager.load fqn, :logic
+
+            [mod, settings]
         end
     end
 
diff --git a/modules/aca/rooms/components/io.rb b/modules/aca/rooms/components/io.rb
index 0dbca74c..8c7cb19a 100644
--- a/modules/aca/rooms/components/io.rb
+++ b/modules/aca/rooms/components/io.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 module Aca::Rooms::Components::Io
+    setting default_routes: {}
+
     def show(source, on: default_outputs)
         source = source.to_sym
         target = Array(on).map(&:to_sym)
diff --git a/modules/aca/rooms/components/power.rb b/modules/aca/rooms/components/power.rb
index 49d63afe..c1e9c5f3 100644
--- a/modules/aca/rooms/components/power.rb
+++ b/modules/aca/rooms/components/power.rb
@@ -1,11 +1,16 @@
 # frozen_string_literal: true
 
 module Aca::Rooms::Components::Power
-    def powerup
+    setting powerup_actions: {}
+
+    setting shutdown_actions: {}
 
+    def powerup
+        logger.debug 'in power mod'
+        :online
     end
 
     def shutdown
-
+        :shutdown
     end
 end

From f6ceabcaf5fcf81b6cee238040a4d8af5ca87de9 Mon Sep 17 00:00:00 2001
From: Kim Burgess <kim@acaprojects.com>
Date: Fri, 30 Nov 2018 18:25:46 +1000
Subject: [PATCH 6/8] (aca:rooms) move generic name and module type def into
 base class

---
 modules/aca/rooms/base.rb   | 3 +++
 modules/aca/rooms/collab.rb | 6 ------
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/modules/aca/rooms/base.rb b/modules/aca/rooms/base.rb
index 70b2303c..0c7b6333 100644
--- a/modules/aca/rooms/base.rb
+++ b/modules/aca/rooms/base.rb
@@ -9,6 +9,9 @@ class Aca::Rooms::Base
     include ::Orchestrator::Constants
     include ::Aca::Rooms::ComponentManager
 
+    generic_name :System
+    implements   :logic
+
     def self.setting(hash)
         previous = @default_settings || {}
         default_settings previous.merge hash
diff --git a/modules/aca/rooms/collab.rb b/modules/aca/rooms/collab.rb
index 32ec1b5d..bdf49d2a 100644
--- a/modules/aca/rooms/collab.rb
+++ b/modules/aca/rooms/collab.rb
@@ -1,13 +1,9 @@
 # frozen_string_literal: true
 
-require 'ostruct'
-
 ::Orchestrator::DependencyManager.load('Aca::Rooms::Base', :logic)
 
 class Aca::Rooms::Collab < Aca::Rooms::Base
     descriptive_name 'ACA Collaboration Space'
-    generic_name :System
-    implements :logic
     description <<~DESC
         Logic and external control API for collaboration spaces.
 
@@ -20,7 +16,5 @@ class Aca::Rooms::Collab < Aca::Rooms::Base
 
     def on_update
         super
-        logger.debug "Methods are: #{self.methods}"
-        logger.debug ::Aca::Rooms::Base.new.methods
     end
 end

From 98752523f6e211fdf4d512fcee83ddb02daaa784 Mon Sep 17 00:00:00 2001
From: Kim Burgess <kim@acaprojects.com>
Date: Fri, 30 Nov 2018 18:26:47 +1000
Subject: [PATCH 7/8] (aca:rooms) auto extend composer from component loader

---
 modules/aca/rooms/component_manager.rb | 1 +
 modules/aca/rooms/components/io.rb     | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/modules/aca/rooms/component_manager.rb b/modules/aca/rooms/component_manager.rb
index 3c7f2b5d..84f48a6b 100644
--- a/modules/aca/rooms/component_manager.rb
+++ b/modules/aca/rooms/component_manager.rb
@@ -133,6 +133,7 @@ def load(component)
                 end
             end
 
+            mod.extend Composer
 
             ::Orchestrator::DependencyManager.load fqn, :logic
 
diff --git a/modules/aca/rooms/components/io.rb b/modules/aca/rooms/components/io.rb
index 8c7cb19a..10126df8 100644
--- a/modules/aca/rooms/components/io.rb
+++ b/modules/aca/rooms/components/io.rb
@@ -27,7 +27,7 @@ def default_outputs
     end
 end
 
-Aca::Rooms::Components::Io.extend ::Aca::Rooms::ComponentManager::Composer
+# Aca::Rooms::Components::Io.extend ::Aca::Rooms::ComponentManager::Composer
 
 Aca::Rooms::Components::Io.compose_with :Power do
     during :powerup do

From ac5a69bda3359531ba51ef0f2a006ac0bcabb8f0 Mon Sep 17 00:00:00 2001
From: Kim Burgess <kim@acaprojects.com>
Date: Fri, 30 Nov 2018 18:31:42 +1000
Subject: [PATCH 8/8] (aca:rooms) add docs

---
 modules/aca/rooms/component_manager.rb | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/modules/aca/rooms/component_manager.rb b/modules/aca/rooms/component_manager.rb
index 84f48a6b..0e0f2bb3 100644
--- a/modules/aca/rooms/component_manager.rb
+++ b/modules/aca/rooms/component_manager.rb
@@ -127,6 +127,9 @@ def load(component)
                       ::Aca::Rooms::Components.const_set component, Module.new
                   end
 
+            # Inject a `setting` class method that pushes back into settings
+            # here via a closure. This enables any settings used by the
+            # component to be declared as `setting key: <default>`.
             mod.define_singleton_method :setting do |hash|
                 settings.merge! hash do |key, _, _|
                     raise "\"#{key}\" declared multiple times in #{fqn}"