From: Rick DeNatale <rick.denatale@...>
Date: 2008-05-08T21:58:15+09:00
Subject: Re: Why can't I redefine "<<" method to allow two parameters?

On Thu, May 8, 2008 at 8:42 AM, Iņaki Baz Castillo <ibc@aliax.net> wrote:
> Hi, very exrtange:
>
>
>  class MyArray < Array
>   alias original_add <<
>   def <<(n,k)
>     original_add "#{n}: #{k}"
>   end
>  end
>
>  my_array = MyArray.new
>  => []
>
>  my_array << ("Header", "Value")
>
>  SyntaxError: compile error
>  (irb):25: syntax error, unexpected ',', expecting ')'
>  my_array << ("Header", "Value")

The parser sees the << OPERATOR as taking a left and right argument,
and turns that into a message send to the left argument.  If you want
to use additional arguments you need to be a bit more explicit and use
a little less syntactic sugar:

my_array.<<("Header","Value") # => ["Header: Value"]

-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/