From: MonkeeSage <MonkeeSage@...>
Date: 2007-12-03T18:25:00+09:00
Subject: Re: question about iterator

On Dec 3, 1:57 am, Robert Klemme <shortcut...@googlemail.com> wrote:
> 2007/12/2, MonkeeSage <MonkeeS...@gmail.com>:
>
>
>
> > On Dec 2, 12:20 am, Paul Private <paulus4...@gmail.com> wrote:
> > > THanks Jordan
> > > this was exactly what I was looking for
>
> > > Paul
>
> > Hi Paul,
>
> > Glad to help. One more thing: it would probably look nicer to hide
> > that behind <=>
>
> > class Cursus
> >   ...
> >   def <=>(other)
> >     self.to_s <=> other.to_s
> >   end
> > end
>
> > ...then you can call cursussen.sort w/o the block.
>
> Just a few picky remarks. :-)  Sorting on the string representation,
> while it may work, is unstable.  It's better to sort based on members
> because with your approach you create a dependency between to_s and
> sorting which is neither necessary nor obvious.
>
> Also, I would only implement this in the class if it is the /default/
> order for instances of Cursus.
>
> Kind regards
>
> robert
>
> --
> use.inject do |as, often| as.you_can - without end

I agree with you. In fact, I would have probably implemented the
courses (Cursus) as ostructs or hashes in the backend. But given to
current implementation, sorting on to_s amounts sorting on @naam,
which is, I think, what the OP was asking for. So, while it is
unstable, generally speaking; here, it amounts to a stable sort on a
(default) instance variable.

Regards,
Jordan