From: "Iñaki Baz Castillo" <ibc@...>
Date: 2008-05-03T18:41:09+09:00
Subject: Re: How to access to an Array element without doing "find" each time

El Sábado, 3 de Mayo de 2008, David A. Black escribió:

> > So "hdr_from" is like a pointer to header("From"), but it's not valid for
> > me since I need the possibility of doing a re-assignement:
> >
> >  header("From") = header("To")
>
> That's not legal Ruby. A method call isn't an lvalue.

Oh, yes, you are right!
Please, let me know if I understand correctly why:

header("From") returns a value so I'm trying to do:
  value1 = value2
that is not legal, is it?


> My advice is to try to learn to think in Ruby, so that you don't keep
> experiencing frustration because of what you perceive Ruby as not
> having. Believe me, Ruby is definitely feature-rich enough to parse
> headers :-)

Well, in fact I've already done the parser (using TreeTop magic). But it's not 
enought with parsing headers (as it would be in HTTP protocol) since I'm 
doing a SIP stack and it can be a proxy (so some headers are modified, new 
added, some deleted... and the rest of message remains equal and is forwarded 
to other server.
That's why I need an efficient way of accessing the @header array of Header 
objets, parse just one of them and keep the whole message as it arrived.



> A lot of Ruby objects need to change their state or contents, without
> changing what object they are. Methods like Array#replace,
> String#replace, and many others, do exactly that. Maybe your message
> objects could "replace" headers with each other, or something like
> that.

Ok, so you mean that I should avoid using "=" and use objects methods to 
replace their content. Nice to know.


Thanks a lot.






-- 
Iñaki Baz Castillo