From: Hugh Sasse Staff Elec Eng <hgs@...>
Date: 2003-09-12T01:40:09+09:00
Subject: Re: What *are* variables? Which are nil now?

On Fri, 12 Sep 2003, ts wrote:

> >>>>> "H" == Hugh Sasse Staff Elec Eng <hgs@dmu.ac.uk> writes:
>
> >> svg% ruby -e 'def nil.to_ary() [12] end; p []+nil'
> >> [12]
> >> svg%
>
> H> so why doesn't this give the TypeError then?
>
>  Because, like I've said, Array#+ call #to_ary and because I've defined
                            ^^^^^^^^^^^^^^^^^^^^
Ah, that was the bit I missed.  Hmm, it's only Array that defines
to_ary out of the box...  Ah, [RubyTalk:72563] explains why there is
a to_a and a to_ary.  This is much clearer now.

The only remaining aspect about this is why the traceback kept
flagging up the error as being in each rather than in the compact!
statement. ... Ah, that's because caller() means caller(1), not
caller(0).  I think I see what is happening here.

>  nil#to_ary it just work
>
> Guy Decoux
>


Thanks for your patience.
>
        Hugh
>
>