Allow touching of records on update positioning

lib/positioning.rb

@@ -18,7 +18,7 @@ def positioning_columns
         @positioning_columns ||= {}
       end
 
-      def positioned(on: [], column: :position)
+      def positioned(on: [], column: :position, touch: false)
         unless base_class?
           raise Error.new "can't be called on an abstract class or STI subclass."
         end
@@ -43,17 +43,17 @@ def positioned(on: [], column: :position)
             end
           end
 
-          define_method(:"prior_#{column}") { Mechanisms.new(self, column).prior }
-          define_method(:"subsequent_#{column}") { Mechanisms.new(self, column).subsequent }
+          define_method(:"prior_#{column}") { Mechanisms.new(self, column, touch).prior }
+          define_method(:"subsequent_#{column}") { Mechanisms.new(self, column, touch).subsequent }
 
           redefine_method(:"#{column}=") do |position|
             send :"#{column}_will_change!"
             super(position)
           end
 
-          before_create { Mechanisms.new(self, column).create_position }
-          before_update { Mechanisms.new(self, column).update_position }
-          before_destroy { Mechanisms.new(self, column).destroy_position }
+          before_create { Mechanisms.new(self, column, touch).create_position }
+          before_update { Mechanisms.new(self, column, touch).update_position }
+          before_destroy { Mechanisms.new(self, column, touch).destroy_position }
 
           define_singleton_method(:"heal_#{column}_column!") do |order = column|
             Healer.new(self, column, order).heal

lib/positioning/mechanisms.rb

@@ -1,8 +1,9 @@
 module Positioning
   class Mechanisms
-    def initialize(positioned, column)
+    def initialize(positioned, column, touch)
       @positioned = positioned
       @column = column.to_sym
+      @touch = touch
     end
 
     def prior
@@ -106,13 +107,21 @@ def move_out_of_the_way
     end
 
     def expand(scope, range)
-      scope.where(@column => range).update_all "#{quoted_column} = #{quoted_column} * -1"
+      records = scope.where(@column => range)
+      records.update_all "#{quoted_column} = #{quoted_column} * -1"
       scope.where(@column => ..-1).update_all "#{quoted_column} = #{quoted_column} * -1 + 1"
+      if @touch
+        records.find_each { it.touch }
+      end
     end
 
     def contract(scope, range)
-      scope.where(@column => range).update_all "#{quoted_column} = #{quoted_column} * -1"
+      records = scope.where(@column => range)
+      records.update_all "#{quoted_column} = #{quoted_column} * -1"
       scope.where(@column => ..-1).update_all "#{quoted_column} = #{quoted_column} * -1 - 1"
+      if @touch
+        records.find_each { it.touch }
+      end
     end
 
     def solidify_position