testing

lib/wukong/widget/reducers/improver.rb

@@ -0,0 +1,63 @@
+module Wukong
+  class Processor
+
+    # A base widget for building more complex improver widgets.
+    class Improver < Processor
+
+      # The current group of records.
+      attr_accessor :group
+
+      # Sets up this improver by defining an initial key (with a
+      # value that is unlikely to be found in real data) and calling
+      # `#zero` with no record.
+      def setup
+        @key = :__first_group__
+        zero
+      end
+
+      def recordize record
+        record.split("\t")
+      end
+
+      #
+      # All kinds of assumptions here,
+      # record is tab-delimited and the
+      # first field is a name of a function
+      # to call
+      #
+      def get_function record
+        record.first
+      end
+
+      # Processes the `record`.
+      def process(record)
+        fields = recordize(record)
+        func   = get_function(fields)
+        case func
+        when 'zero' then
+          yield zero
+        when 'accumulate' then
+          accumulate(fields[1..-1])
+        when 'improve' then
+          yield improve(fields.first, self.group)
+          self.group = []
+        else
+          raise NoMethodError, "undefined method #{func} for Improver"
+        end
+      end
+
+      # Starts accumulation for a new key. Return what you would
+      # with no improvements.
+      def zero
+        self.group = []
+      end
+
+      # Accumulates another +record+.
+      #
+      # @param [Object] record
+      def accumulate record
+        self.group << record
+      end
+    end
+  end
+end