class Middleman::CoreExtensions::Collections::LazyCollectorStep

def value(ctx=nil)
  data = @parent.value(ctx)
  original_block = @block
  if original_block
    b = if ctx
      ::Proc.new do |*args|
        ctx.instance_exec(*args, &original_block)
      end
    else
      original_block
    end
  end
  data.send(@name, *@args.deep_dup, &b)
end