On 21/10/2007, Dan Yoder <dan@[...].com>  wrote:
>  module Kernel
>    def with(object,&block)
>      object.instance_eval &block
>    end
>  end
> 
>  with([1,2,3]) { length } # => 3

You could even do something like this:

module Kernel
  def with_block(*args, &block)
    send(*args) { |obj| obj.instance_eval &block }
  end
end

['asdf', 'jkl', 'semicolon'].with_block(:map) { length } # =>  [4, 3, 9]

That would allow something like this:
<% with_block(:form_for, :user, @user) { %> 
  <%= text_field :name %> 
  <%= text_field :email %> 
  <%= password_field :password %> 
<% } %> 

It may or may not be useful, but it's fun.