From: dblack@...
Date: 2007-07-07T21:04:28+09:00
Subject: Re: Array#values_at bug?

Hi --

On Sat, 7 Jul 2007, John Lam (CLR) wrote:

> There's also similar behavior in other range-like entities in strings:
>
> "foo"[3,0] == ""
>
> But
>
> "foo"[4,0] == nil
>
> Do folks depend on this kind of behavior? I'll need to add a special
> case to my string implementation to replicate this behavior in
> IronRuby. Or should I do the correct thing and make "foo"[3,0] ==
> nil?

The slippery slope :-)  I admit I'm a compatability fan, even for
corner cases (though not for bugs, so obviously if Matz rules it a bug
that's a different matter).

Meanwhile, I'm wondering whether the behavior is based on the idea
that "foo"[3] is a position to the right of the second 'o' but to the
left of the end-of-string (in the regex manner), so that you're still
looking at the string (not nil) but at a point where there are zero
characters left.  So asking for 0 characters from that point gives you
a string rather than nil, just as "foo"[1,0] would.  I don't know
whether that was how it was designed but I think it might be.


David

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