module vs. class

app/models/report/filter.rb

@@ -1,17 +1,15 @@
 require "set"
 
-module Report::Filter
-  extend self
-
-  def all
+class Report::Filter
+  def self.all
     @all ||= Set[]
   end
 
-  def all_grouped
+  def self.all_grouped
     all.group_by { |f| f.applies_for }.to_a.sort { |a,b| a.first.to_s <=> b.first.to_s }
   end
 
-  def from_hash
+  def self.from_hash
     raise NotImplementedError
   end
 end

app/models/report/filter/base.rb

@@ -1,4 +1,4 @@
-module Report::Filter
+class Report::Filter
   class Base < Report::Chainable
     Report::Operator.load
 

app/models/report/group_by/ruby_aggregation.rb

@@ -1,4 +1,4 @@
-module Report::GroupBy
+class Report::GroupBy
   module RubyAggregation
     def responsible_for_sql?
       false

app/models/report/group_by/singleton_value.rb

@@ -1,4 +1,4 @@
-module Report::GroupBy
+class Report::GroupBy
   class SingletonValue < Base
     dont_display!
   end

app/models/report/group_by/sql_aggregation.rb

@@ -1,4 +1,4 @@
-module Report::GroupBy
+class Report::GroupBy
   module SqlAggregation
     def responsible_for_sql?
       true