Implement Recipe{.,#}compose_macro

features/recipe_compose_macro.feature

@@ -0,0 +1,15 @@
+Feature: `compose_macro' recipe keyword
+
+  Scenario: allows macro composition
+    Given a recipe with:
+      """
+      macro :hello do |prefix, *args|
+        echo 'hello %s %s' % [prefix, args.join(', ')]
+      end
+
+      compose_macro :hello_composed, :hello, 'composed'
+
+      hello_composed :foo, :bar
+      """
+    When I successfully execute the recipe
+    Then the output must contain "hello composed foo, bar"

lib/producer/core/recipe.rb

@@ -5,6 +5,10 @@ module Producer
         def define_macro(name, block)
           define_method(name) { |*args| task name, *args, &block }
         end
+
+        def compose_macro(name, meth, *base_args)
+          define_method(name) { |*args| send meth, *(base_args + args) }
+        end
       end
 
       attr_reader :env, :tasks
@@ -27,11 +31,17 @@ module Producer
       end
 
       def macro(name, &block)
-        define_singleton_method(name) do |*args|
+        define_singleton_method name do |*args|
           task "#{name}", *args, &block
         end
       end
 
+      def compose_macro(name, meth, *base_args)
+        define_singleton_method name do |*args|
+          send meth, *(base_args + args)
+        end
+      end
+
       def test_macro(name, &block)
         Condition.define_test(name, block)
       end