module.rb in attribute_predicates-0.1.1

- old
+ new
@@ -1,37 +1,81 @@
 module PluginAWeek #:nodoc:
   module AttributePredicates
-    module Module
-      def self.included(base) #:nodoc:
-        base.class_eval do
-          [:attr, :attr_reader, :attr_writer, :attr_accessor].each do |method|
-            alias_method_chain method, :predicates
+    module Extensions
+      # Adds support for automatically defining predicate methods using +attr_predicate+
+      # when defining attributes using +attr+, +attr_reader+, +attr_reader+, and
+      # +attr_accessor+.
+      # 
+      # == Examples
+      # 
+      # The predicate methods for attributes checks whether the value is blank?
+      # for determining whether true or false should be returned.  For example,
+      # 
+      #   class Person
+      #     attr_accessor :value
+      #   end
+      #   
+      #   p = Person.new
+      #   p.value = false
+      #   p.value?    # => false
+      #   
+      #   p.value = true
+      #   p.value?    # => true
+      #   
+      #   p.value = []
+      #   p.value?    # => false
+      #   
+      #   p.value = [false]
+      #   p.value?    # => true
+      module Module
+        def self.included(base) #:nodoc:
+          base.class_eval do
+            %w(attr attr_reader attr_writer attr_accessor).each do |method|
+              alias_method "#{method}_without_predicates", method
+              alias_method method, "#{method}_with_predicates"
+            end
           end
         end
-      end
-      
-      def attr_with_predicates(*args) #:nodoc:
-        attr_without_predicates(*args)
-        attr_predicate(args.first)
-      end
-      
-      [:attr_reader, :attr_writer, :attr_accessor].each do |method|
-        define_method("#{method}_with_predicates") do |*symbols|
-          send("#{method}_without_predicates", *symbols)
-          symbols.each {|symbol| attr_predicate(symbol)}
+        
+        # Defines a predicate method, using +attr_predicate+, in addition to the
+        # attribute accessors.  For example,
+        # 
+        #   module Mod
+        #     attr :is_okay
+        #   end
+        #   
+        #   Mod.instance-methods.sort # => ["is_okay", "is_okay?"]
+        def attr_with_predicates(*args)
+          attr_without_predicates(*args)
+          attr_predicate(args.first)
         end
-      end
-      
-      private
-        # Returns true if the specified variable is not blank, otherwise false
-        def attr_predicate(symbol)
-          define_method("#{symbol}?") do
-            !instance_variable_get("@#{symbol}").blank?
+        
+        [:attr_reader, :attr_writer, :attr_accessor].each do |method|
+          define_method("#{method}_with_predicates") do |*symbols|
+            send("#{method}_without_predicates", *symbols)
+            symbols.each {|symbol| attr_predicate(symbol)}
           end
         end
+        
+        private
+          # Returns true if the specified variable is not blank, otherwise false
+          def attr_predicate(symbol)
+            define_method("#{symbol}?") do
+              value = instance_variable_get("@#{symbol}")
+              if value.respond_to?(:blank?)
+                # Use ActiveSupport's implementation
+                !value.blank?
+              elsif value.respond_to?(:empty?)
+                !value.empty?
+              else
+                !!value
+              end
+            end
+          end
+      end
     end
   end
 end
 
 ::Module.class_eval do
-  include PluginAWeek::AttributePredicates::Module
+  include PluginAWeek::AttributePredicates::Extensions::Module
 end