"Andrei Alexandrescu" <[EMAIL PROTECTED]> writes:
> "David Abrahams" <[EMAIL PROTECTED]> wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
>
>> Yeah, I haven't always been very comfortable with the
>> value-per-character of mpl::for_each -- it seems to have similar
>> properties to std::for_each in that way. It's got certain advantages
>> for re-use:
>>
>> 1. You can use different sequence types (I know Andrei doesn't buy
>> this one, but I still do; the concept of tuple-as-type-sequence
>> being one motivator)
>
> My understanding is that front and pop_front work with different sequence
> types, isn't that so?
Yeah, but I don't think a vector turns to void_ after you've popped
everything off the front ;-)
> If that's the case, (1) illustrates no advantage of the complicated
> version over the simple version.
It's all in the non-generic termination condition.
>> I've been talking with Aleksey recently about how to improve the
>> syntactic situation without losing the separation of concerns that we
>> get, but we didn't come up with anything convincingly better.
>
> The template pattern matching just makes it too easy... :o)))
It's easy if you can think that way, but not neccessarily clear.
--
David Abrahams
[EMAIL PROTECTED] * http://www.boost-consulting.com
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