1 files changed, 74 insertions, 0 deletions
diff --git a/lib/rake/task_arguments.rb b/lib/rake/task_arguments.rb
new file mode 100644
index 0000000000..ab404d67f5
--- /dev/null
+++ b/lib/rake/task_arguments.rb
@@ -0,0 +1,74 @@
+module Rake
+
+  ####################################################################
+  # TaskArguments manage the arguments passed to a task.
+  #
+  class TaskArguments
+    include Enumerable
+
+    attr_reader :names
+
+    # Create a TaskArgument object with a list of named arguments
+    # (given by :names) and a set of associated values (given by
+    # :values).  :parent is the parent argument object.
+    def initialize(names, values, parent=nil)
+      @names = names
+      @parent = parent
+      @hash = {}
+      names.each_with_index { |name, i|
+        @hash[name.to_sym] = values[i] unless values[i].nil?
+      }
+    end
+
+    # Create a new argument scope using the prerequisite argument
+    # names.
+    def new_scope(names)
+      values = names.collect { |n| self[n] }
+      self.class.new(names, values, self)
+    end
+
+    # Find an argument value by name or index.
+    def [](index)
+      lookup(index.to_sym)
+    end
+
+    # Specify a hash of default values for task arguments. Use the
+    # defaults only if there is no specific value for the given
+    # argument.
+    def with_defaults(defaults)
+      @hash = defaults.merge(@hash)
+    end
+
+    def each(&block)
+      @hash.each(&block)
+    end
+
+    def method_missing(sym, *args, &block)
+      lookup(sym.to_sym)
+    end
+
+    def to_hash
+      @hash
+    end
+
+    def to_s
+      @hash.inspect
+    end
+
+    def inspect
+      to_s
+    end
+
+    protected
+
+    def lookup(name)
+      if @hash.has_key?(name)
+        @hash[name]
+      elsif @parent
+        @parent.lookup(name)
+      end
+    end
+  end
+
+  EMPTY_TASK_ARGS = TaskArguments.new([], [])
+end