Report can define nested rules

lib/open_food_network/reports/rule.rb

@@ -1,5 +1,7 @@
 module OpenFoodNetwork::Reports
   class Rule
+    attr_reader :next
+
     def group(&block)
       @group = block
     end
@@ -8,9 +10,13 @@ module OpenFoodNetwork::Reports
       @sort = block
     end
 
+    def organise(&block)
+      @next = Rule.new
+      @next.instance_eval &block
+    end
+
     def to_h
       {group_by: @group, sort_by: @sort}
     end
-
   end
 end

spec/lib/open_food_network/reports/report_spec.rb

@@ -2,43 +2,57 @@ require 'open_food_network/reports/report'
 
 module OpenFoodNetwork::Reports
   class TestReport < Report
-    header 'One', 'Two', 'Three'
+    header 'One', 'Two', 'Three', 'Four'
 
     columns do
       column { |o| o[:one] }
       column { |o| o[:two] }
       column { |o| o[:three] }
+      column { |o| o[:four] }
     end
 
     organise do
       group { |o| o[:one] }
       sort  { |o| o[:two] }
+
+      organise do
+        group { |o| o[:three] }
+        sort  { |o| o[:four] }
+      end
     end
   end
 
   describe Report do
     let(:report) { TestReport.new }
     let(:rules_head) { TestReport.class_variable_get(:@@rules_head) }
-    let(:data) { {one: 1, two: 2, three: 3} }
+    let(:data) { {one: 1, two: 2, three: 3, four: 4} }
 
     it "returns the header" do
-      report.header.should == %w(One Two Three)
+      report.header.should == %w(One Two Three Four)
     end
 
     it "returns columns as an array of procs" do
       report.columns[0].call(data).should == 1
       report.columns[1].call(data).should == 2
       report.columns[2].call(data).should == 3
+      report.columns[3].call(data).should == 4
     end
 
     describe "rules" do
       let(:group_by) { rules_head.to_h[:group_by] }
       let(:sort_by) { rules_head.to_h[:sort_by] }
+      let(:next_group_by) { rules_head.next.to_h[:group_by] }
+      let(:next_sort_by) { rules_head.next.to_h[:sort_by] }
 
-      it "constructs a linked list of rules" do
+      it "constructs the head of the rules list" do
         group_by.call(data).should == 1
         sort_by.call(data).should == 2
       end
+
+      it "constructs nested rules" do
+        next_group_by.call(data).should == 3
+        next_sort_by.call(data).should == 4
+      end
     end
   end
 end

spec/lib/open_food_network/reports/rule_spec.rb

@@ -14,5 +14,10 @@ module OpenFoodNetwork::Reports
       rule.sort &proc
       rule.to_h.should == {group_by: nil,  sort_by: proc}
     end
+
+    it "can define a nested rule" do
+      rule.organise &proc
+      rule.next.should be_a Rule
+    end
   end
 end