[boost] Re: Fusion plan [was Re: tuple patch (constructing from apair)]

From: Jonathan Turkanis (technews_at_[hidden])
Date: 2005-02-15 15:53:28

Joel de Guzman wrote:
> Jonathan Turkanis wrote:
>> Joel de Guzman wrote:

>>> 5) Provide a tuple TR1 interface on top of fusion.
>>> 6) Provide a backward compatible interface (for old tuples) on
>>>    top of fusion.

>> Also, I think having both 5) and 6) will be confusing. I'd prefer to
>> get rid of 6). This will obviously break some code, but it will be
>> much easier to adapt old code to the new interface than it was,
>> e.g., to adapt code to use the new iterator adaptors.
>
> 5 and 6 will have to either-or through a PP define. Yes, it
> can't be both at the same time. We can deprecate 6 and
> phase it out in the future. We can't simply kill it now.
> TR1 deos not provide a way to extend a tuple, for example.

Okay, I thought people who used cons lists were relying on an implementation
detail, but I see that it is  documented under "advanced features."

Still, I'm not sure why you can't eliminate 6) at the same time you introduce
fusion. People who need extensible tuples can use fusion sequences.

Jonathan