From: Marcin 'Qrczak' Kowalczyk <qrczak@...>
Date: 2002-11-17T19:22:41+09:00
Subject: Re: Array#next - Enumerable#next ?

Fri, 15 Nov 2002 10:41:45 +0900, ahoward <ahoward@fsl.noaa.gov> pisze:

> i don't view this as a problem - you are viewing the next method as an
> iterator, which in definitively is not.  it is an instance method of Array,
> and uses instance variables.  i would define Array#next as the the next
> object the Array is willing to give me.

It puts the state of an iteration over the array inside the array,
which is evil, even if looks convenient. Traps:

- Iteration within another iteration.
- Iteration from different threads.
- Aborting an iteration early and then starting it again without
  resetting the iteration state.

> if you call a method manipulating Array#size, from another method
> manipulating Array#size - would you be suprised that size had
> changed?

No, because I'm changing the array. But in the above I'm not changing
the array, only iterate over it. In other words it turns a non-destructive
operation of iterating over the array into a destructive operation which
modifies the array.

-- 
  __("<      Marcin Kowalczyk
  \__/     qrczak@knm.org.pl
   ^^    http://qrnik.knm.org.pl/~qrczak/