Range returning an array

[Joseph Rushton Wakeling]

On 04/09/2013 10:37 PM, H. S. Teoh wrote:
> Congratulations! You've created your first transient range. :)

:-)

Well, the problem isn't transience per se.  It's acceptable that popFront()
overwrite previous returned values -- the problem is strictly that in deciding
that the range is empty, the 'last' value is overwritten.

> Personally, my preference is to let the user code call .dup to copy the
> value instead of aliasing it. The crux of the issue is that returning an
> array is by reference, so it's equivalent to returning a reference.  If
> you were calling a ref function, you'd be careful about assuming whether
> its value would change afterwards. The problem is that the range API
> conflates by-ref and by-value .front's, and there's currently no way to
> tell them apart aside from knowing the specifics of the range you're
> dealing with.

I'll give the take-by-dup rather than return-by-dup option a go just to see if
it can work.  Unfortunately in practice it's a bit more complex because some of
my use cases might want to return a more complex data structure than just an
array (e.g. a struct containing one or two arrays and some values).

Thanks for the thoughts and especially for the in-depth explanation on
transience! :-)