From: brabuhr@...
Date: 2009-11-25T01:36:22+09:00
Subject: Re: Difference between << and += for Strings and Arrays. Bug?

On Tue, Nov 24, 2009 at 11:11 AM, Pieter Hugo <pieter@internext.co.za> wrote:
> Thanks for the quick responses and insights. While I understand the
> issue now I must confess that it perturbs my 'least surprise'
> expectation. Why was it decided that '<<' should reference the original
> object but '+' should create a new object.

Consider that b+=a is just a nice shorthand for b = b + a (or b = b.+(a)).

a = [1, 2]
b = [3, 4]
c = b + a

Would it be desirable for the :+ message to modify the object represented by b?