Report can define and retrieve columns

lib/open_food_network/reports/report.rb

@@ -1,3 +1,5 @@
+require 'open_food_network/reports/row'
+
 module OpenFoodNetwork::Reports
   class Report
     # -- API
@@ -5,10 +7,19 @@ module OpenFoodNetwork::Reports
       @@header
     end
 
+    def columns
+      @@columns.to_a
+    end
+
 
     # -- DSL
     def self.header(*columns)
       @@header = columns
     end
+
+    def self.columns(&block)
+      @@columns = Row.new
+      @@columns.instance_eval(&block)
+    end
   end
 end

lib/open_food_network/reports/row.rb

@@ -0,0 +1,16 @@
+module OpenFoodNetwork::Reports
+  class Row
+    def initialize
+      @columns = []
+    end
+
+
+    def column(&block)
+      @columns << block
+    end
+
+    def to_a
+      @columns
+    end
+  end
+end