lib/prelude/monad.rb in prelude-0.0.3 vs lib/prelude/monad.rb in prelude-0.0.5

@@ -21,50 +21,46 @@
 #     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 #++
 
 module Prelude
 
-  # $Id: monad.rb 13 2006-09-11 05:19:16Z prelude $
+  # $Id: monad.rb 34 2007-10-23 21:38:09Z prelude $
   #
+  # Defines monadic behavior for anything willing to include it.
   module Monad
-    State = {}
+    M_STATE = {}
 
     def wrap
-      State[object_id] = self
+      M_STATE[object_id] = self
       self
     end
 
     def unwrap
-      State[object_id]
+      M_STATE[object_id]
     end
 
     def empty
-      State[object_id] = nil
+      M_STATE[object_id] = nil
       self
     end
     
     def Monad.join(arr)
       r = []
       arr.each {|a| r.push *a}
       r
     end
 
     def bind(f=nil)
-      case
-      when f.kind_of?(Symbol) || f.kind_of?(Method) || f.kind_of?(Proc) :
-          State[object_id] = f.to_proc.call(State[object_id])
+      wrap unless M_STATE[object_id]
+      if f.kind_of?(Symbol) || f.kind_of?(Method) || f.kind_of?(Proc)
+        M_STATE[object_id] = f.to_proc.call(M_STATE[object_id])
         self
-        
-#      when f.kind_of?(Proc) :
-#          State[object_id] = f.call(State[object_id])
-#        self
-
       else
         f
-      end # case
+      end # if
     end # bind
 
-    alias << bind
+    alias >> bind
 
   end # Monad
 
 #   class Maybe < Monad