From: MikkelFJ <mikkelj-anti-spam@...1.dknet.dk>
Date: 2001-09-02T22:11:32+09:00
Subject: [ruby-talk:20699] Re: RCR: non-bang equivalent to []=


"Tobias Reif" <tobiasreif@pinkjuice.com> wrote in message
news:3B911E57.8090306@pinkjuice.com...
> Hi David,

> Would the following make sense?

I think it makes perfect sense. It relates to functional programming and the
concept of "referential transparency" (the non-bang version).

Arrays are perhaps not the most brilliant example of non-destructive update,
but if you look at a set or a list, where you can have two versions sharing
most of the non-modified datastructure, it starts to make sense.

But it would complicate the internals of Ruby because it would either have
to track usage count on datastructures, or assume that datastructures are
not modified by default - which isn't very rubish.

A non-destructive update that performs a full copy each time is generally
not very useful. An explicit duplication is probably better here, as someone
suggested.

Even so - it is nice to have the semantics in place.

Mikkel