lib/craft.rb in craft-0.0.2 vs lib/craft.rb in craft-0.1.0

@@ -5,58 +5,61 @@
 #
 # Examples
 #
 #   module Transformations
 #     IntegerTransform = lambda { |n| Integer n.text }
+#     Timestamp        = lambda { Time.now }
 #   end
 #
 #   class Person < Craft
 #     include Transformations
 #
 #     one :name, 'div.name'
 #     one :age, 'div.age', IntegerTransform
 #     many :friends, 'li.friend', Person
+#     stub :created_at, Timestamp
 #   end
 #
 class Craft
   class << self
-    # We alias call to new so that crafted objects may nest themselves or other
-    # crafted objects as transformations.
-    alias call new
+    # Returns an Array of names for the attributes defined in the class.
+    attr :attribute_names
 
-    # Define a method that extracts a collection of values from a parsed
+    # Define an attribute that extracts a collection of values from a parsed
     # document.
     #
-    # name  - The Symbol name of the method.
+    # name  - The Symbol name of the attribute.
     # paths - One or more String XPath of CSS queries. An optional Proc
     #         transformation on the extracted value may be appended. If none is
     #         appended, the default transformation returns the stripped String
     #         value of the node.
     #
-    # Returns an Array.
+    # Returns nothing.
     def many(name, *paths)
-      transform = pop_transformation paths
+      transform = pop_transform_from_paths paths
+      @attribute_names << name
 
       define_method name do
-        @node.search(*paths).map { |node| transform.call node }
+        @node.search(*paths).map { |node| instance_exec node, &transform }
       end
     end
 
-    # Define a method that extracts a single value from a parsed document.
+    # Define an attribute that extracts a single value from a parsed document.
     #
-    # name  - The Symbol name of the method.
+    # name  - The Symbol name of the attribute.
     # paths - One or more String XPath of CSS queries. An optional Proc
     #         transformation on the extracted value may be appended. If none is
     #         appended, the default transformation returns the stripped String
     #         value of the node.
     #
-    # Returns an Object.
+    # Returns nothing.
     def one(name, *paths)
-      transform = pop_transformation paths
+      transform = pop_transform_from_paths paths
+      @attribute_names << name
 
       define_method name do
-        transform.call @node.at(*paths)
+        instance_exec @node.at(*paths), &transform
       end
     end
 
     # Parse a document.
     #
@@ -65,27 +68,60 @@
     # Returns an instance of its self.
     def parse(body)
       new Nokogiri body
     end
 
+    # Define an attribute that returns a value without parsing the document.
+    #
+    # name  - The Symbol name of the attribute.
+    # value - Some value the attribute should return. If given a Proc, the
+    #         value will be generated dynamically (default: nil).
+    #
+    # Returns nothing.
+    def stub(name, value = nil)
+      @attribute_names << name
+
+      define_method name do
+        value.respond_to?(:call) ? instance_exec(&value) : value
+      end
+    end
+
+    def to_proc
+      klass = self
+      ->(node) { klass.new node, self }
+    end
+
     private
 
-    def pop_transformation(array)
-      if array.last.respond_to? :call
+    def inherited(subclass)
+      subclass.instance_variable_set :@attribute_names, []
+    end
+
+    def pop_transform_from_paths(array)
+      if array.last.respond_to? :to_proc
         array.pop
       else
-        Module.new do
-          def self.call(node)
-            node.text.strip if node
-          end
-        end
+        ->(node) { node.text.strip if node }
       end
     end
   end
 
+  attr :parent
+
   # Craft a new object.
   #
   # node - A Nokogiri::XML::Node.
-  def initialize(node)
+  def initialize(node, parent = nil)
     @node = node
+    @parent = parent
+  end
+
+  # Returns the Hash attributes.
+  def attributes
+    Hash[attribute_names.map { |key| [key, self.send(key)] }]
+  end
+
+  # Returns an Array of names for the attributes on this object.
+  def attribute_names
+    self.class.attribute_names
   end
 end