From: "Brian Schröder" <ruby.brian@...>
Date: 2005-09-01T19:49:07+09:00
Subject: Re: implementing the "each" method for own classes

On 01/09/05, Robert Klemme <bob.news@gmx.net> wrote:
> Brian Schr�der wrote:
> > On 01/09/05, Philipp Huber <huber.philipp@gmail.com> wrote:
> >> actually i did test it with a queue filled with a few elements. as
> >> you said the condition for the while loop should be testet at the
> >> beginning, otherwise nil could be returned.
> >> so my code looks like this:
> >>
> >> def each
> >>   node=@head
> >>   while node=node.next
> >>    yield node.content
> >>   end
> >> end
> >>
> >> do you have an example for the second remark, as i don't quite
> >> understand what you mean
> 
> Just put "return self" or just "self" in the last line of your method
> #each.
> 
> > Sorry for posting something that untested. But as I look again you
> > continue to have bugs in your code.
> >
> > You are missing the first element. The following should work and also
> > return self. That allows you to do something like the following:
> 
> That's only true if head is nil for an empty queue.  There are
> implementations out there (for example java.util.LinkedList) where the
> first element is never null.  It might be though that it makes sense only
> for a doubly linked list.
> 
> > queue.each do | element | element.seen += 1 end.each do | element |
> > puts element end
> >
> > Beware that the above example does not make that much sense, but I do
> > not have a better example ready.
> >
> > def each
> >   node=@head
> >   while node
> >     yield node.content
> >     node=node.next
> >   end
> >   self
> > end
> 
> That's what I suggested, isn't it?

It is - I'm sorry, I'm task-switching in my mind too fast at the
moment. I will concentrate on my thesis now ...

best regards,

Brian

> 
> Kind regards
> 
>     robert
> 
> 
> 


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