Report can define basic rules

lib/open_food_network/reports/report.rb

@@ -1,4 +1,5 @@
 require 'open_food_network/reports/row'
+require 'open_food_network/reports/rule'
 
 module OpenFoodNetwork::Reports
   class Report
@@ -21,5 +22,10 @@ module OpenFoodNetwork::Reports
       @@columns = Row.new
       @@columns.instance_eval(&block)
     end
+
+    def self.organise(&block)
+      @@rules_head = Rule.new
+      @@rules_head.instance_eval(&block)
+    end
   end
 end

lib/open_food_network/reports/rule.rb

@@ -0,0 +1,16 @@
+module OpenFoodNetwork::Reports
+  class Rule
+    def group(&block)
+      @group = block
+    end
+
+    def sort(&block)
+      @sort = block
+    end
+
+    def to_h
+      {group_by: @group, sort_by: @sort}
+    end
+
+  end
+end

spec/lib/open_food_network/reports/report_spec.rb

@@ -9,10 +9,16 @@ module OpenFoodNetwork::Reports
       column { |o| o[:two] }
       column { |o| o[:three] }
     end
+
+    organise do
+      group { |o| o[:one] }
+      sort  { |o| o[:two] }
+    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} }
 
     it "returns the header" do
@@ -24,5 +30,15 @@ module OpenFoodNetwork::Reports
       report.columns[1].call(data).should == 2
       report.columns[2].call(data).should == 3
     end
+
+    describe "rules" do
+      let(:group_by) { rules_head.to_h[:group_by] }
+      let(:sort_by) { rules_head.to_h[:sort_by] }
+
+      it "constructs a linked list of rules" do
+        group_by.call(data).should == 1
+        sort_by.call(data).should == 2
+      end
+    end
   end
 end

spec/lib/open_food_network/reports/rule_spec.rb

@@ -0,0 +1,18 @@
+require 'open_food_network/reports/rule'
+
+module OpenFoodNetwork::Reports
+  describe Rule do
+    let(:rule) { Rule.new }
+    let(:proc) { Proc.new {} }
+
+    it "can define a group proc and return it in a hash" do
+      rule.group &proc
+      rule.to_h.should == {group_by: proc, sort_by: nil}
+    end
+
+    it "can define a sort proc and return it in a hash" do
+      rule.sort &proc
+      rule.to_h.should == {group_by: nil,  sort_by: proc}
+    end
+  end
+end