Add HashWithStructAccess#has? and HashWithStructAccess#lookup!

lib/confstruct/hash_with_struct_access.rb

@@ -91,6 +91,20 @@ def deferred! &block
       Deferred.new(&block)
     end
 
+    def has? key_path
+      val = self
+      keys = key_path.split(/\./)
+      keys.each do |key|
+        return false if val.nil?
+        if val.respond_to?(:has_key?) and val.has_key?(key.to_sym)
+          val = val[key.to_sym]
+        else
+          return false
+        end
+      end
+      return true
+    end
+
     def inspect
       r = self.keys.collect { |k| "#{k.inspect}=>#{self[k].inspect}" }
       "{#{r.compact.join(', ')}}"
@@ -100,8 +114,18 @@ def is_a? klazz
       klazz == @@hash_class or super
     end
 
-    def values
-      keys.collect { |k| self[k] }
+    def lookup! key_path
+      val = self
+      keys = key_path.split(/\./)
+      keys.each do |key|
+        return nil if val.nil?
+        if val.respond_to?(:has_key?) and val.has_key?(key.to_sym)
+          val = val[key.to_sym]
+        else
+          return nil
+        end
+      end
+      return val
     end
 
     def method_missing sym, *args, &block
@@ -144,6 +168,10 @@ def symbolize key
       self.class.symbolize(key)
     end
 
+    def values
+     keys.collect { |k| self[k] }
+    end
+
     protected 
     def do_deep_merge! source, target
       source.each_pair do |k,v|

spec/confstruct/hash_with_struct_access_spec.rb

@@ -67,6 +67,16 @@
       end
     end
 
+    it "should properly respond to #has?" do
+      @hwsa.has?('github.url').should be_true
+      @hwsa.has?('github.foo.bar.baz').should be_false
+    end
+
+    it "should properly respond to #lookup!" do
+      @hwsa.lookup!('github.url').should == @hash[:github][:url]
+      @hwsa.lookup!('github.foo.bar.baz').should be_nil
+    end
+
     it "should provide introspection" do
       @hwsa.should_respond_to(:project)
       @hash.keys.each do |m|