From: "David A. Black" <dblack@...>
Date: 2001-09-02T20:40:05+09:00
Subject: [ruby-talk:20697] Re: Iterating by links

Hi --

On Sun, 2 Sep 2001, Joel VanderWerf wrote:

> Also, nil (or false) terminates the enumeration without being included in 
> it, which is the classic linked list semantics.

True, but classically speaking, all you're looking for is a pointer or
nil.  The problem here is that nil or false could legitimately be the
next legitimate item in the list.

I wonder whether there's a layer missing -- something like a
"Linkable" module, which expected definitions of previous and next.
Otherwise it might be sort of like trying to describe a ternary state
with a binary operator.  (I'm not sure whether I mean that literally
or figuratively :-)


David

-- 
David Alan Black
usually dblack@candle.superlink.net
writing from dblack@saturn.superlink.net