From: zhoujing@... (TOTO)
Date: 2003-01-02T22:49:36+09:00
Subject: Re: How to extend Hash

matz@ruby-lang.org (Yukihiro Matsumoto) wrote in message news:<1041481402.405681.3205.nullmailer@picachu.netlab.jp>...
> Hi,
> 
> In message "How to extend Hash"
>     on 03/01/02, TOTO <zhoujing@comp.nus.edu.sg> writes:
> 
> |I am trying to extend the Hash class so that I can "Insert the content
> |of a Hash object to another Hash object".
> |
> |However, the internal code for Hash is written in c. Is it possible to
> |extend the class using ruby itself? How, since we don't know the
> |internal data structures of class Hash.
> 
> It is possible, just like other Ruby-defined classes.  But first you
> can check out "update" method for Hash class.
> 
> 							matz.
> 
> ------------------------------------------------------------ Hash#update
>      hsh.update( anOtherHash ) -> hsh
> ------------------------------------------------------------------------
>      Adds the contents of anOtherHash to hsh, overwriting entries with
>      duplicate keys with those from anOtherHash.
>         h1 = { "a" => 100, "b" => 200 }
>         h2 = { "b" => 254, "c" => 300 }
>         h1.update(h2)   #=> {"a"=>100, "b"=>254, "c"=>300}


Thanks. Yes. That is exactly what I wanted.

However, I still don't understand how I can add methods to class Hash
with Ruby, since I don't know the internal structure of it.

Thank you very much!