lib/transflow/publisher.rb in transflow-0.2.0 vs lib/transflow/publisher.rb in transflow-0.3.0

@@ -1,15 +1,36 @@
 require 'wisper'
+require 'kleisli'
 
+require 'transflow/errors'
+
 module Transflow
   class Publisher
     include Wisper::Publisher
 
     attr_reader :name
 
     attr_reader :op
 
+    def self.[](name, op, options = {})
+      type =
+        if options[:monadic]
+          Monadic
+        else
+          self
+        end
+      type.new(name, op)
+    end
+
+    class Monadic < Publisher
+      def call(*args)
+        op.(*args)
+          .or { |result| broadcast_failure(*args, result) and Left(result) }
+          .>-> value { broadcast_success(value) and Right(value) }
+      end
+    end
+
     class Curried < Publisher
       attr_reader :publisher
 
       attr_reader :arity
 
@@ -50,14 +71,27 @@
       op.is_a?(Proc) ? op.arity : op.method(:call).arity
     end
 
     def call(*args)
       result = op.call(*args)
-      broadcast(:"#{name}_success", result)
+      broadcast_success(result)
       result
-    rescue => err
-      broadcast(:"#{name}_failure", *args, err)
-      raise err
+    rescue StepError => err
+      broadcast_failure(*args, err) and raise(err)
     end
     alias_method :[], :call
+
+    def subscribe(listeners, *args)
+      Array(listeners).each { |listener| super(listener, *args) }
+    end
+
+    private
+
+    def broadcast_success(result)
+      broadcast(:"#{name}_success", result)
+    end
+
+    def broadcast_failure(*args, err)
+      broadcast(:"#{name}_failure", *args, err)
+    end
   end
 end