From: Dave Thomas <Dave@...>
Date: 2000-12-04T00:38:46+09:00
Subject: [ruby-talk:6769] Re: printing/accessing arrays and hashes

matz@zetabits.com (Yukihiro Matsumoto) writes:

> Probably Hash#fetch equivalent for Array is good answer.  What do you
> guys think is the best name for it?  Array#get? Array#fetch?

at (for the Smalltalkers out there).

> This is iteresting comment.  Let's discuss.  If index is out of
> bound, what should [] return?  nil or empty array?

We need to choose an underlying semantic.

For me, the primitive operation here is array element indexing,
a[]. Everything else is defined in terms of it.

  a[x..y] should return [ a[x] + a[x.succ] ...a[y] ]

So, if a = [9, 8, 7]

   a[0] = 9
   a[1] = 8
   a[2] = 7
   a[3] = nil
   a[4] = nil

   a[1,2] = [ a[1], a[2] ]             => [ 8, 7 ]
   a[1,4] = [ a[1], a[2], a[3], a[4] ] => [ 8, 7, nil, nil ]
   a[5,2] = [ a[5], a[6] ]             => [ nil, nil ]

   a[2..5] = [ a[2], a[3], a[4], a[5]] => [ 7, nil, nil, nil ]

Regards


Dave



ps. How did the conference go? Will anyone be posting a report?