[boost] Re: [utility] question on prior(x,n)

From: Daniel Frey (daniel.frey_at_[hidden])
Date: 2004-02-26 04:45:28

David Abrahams wrote:
> Daniel Frey <daniel.frey_at_[hidden]> writes:
> 
>>>Incidentally, it's almost always possible to detect whether the first
>>>argument supports operator += or operator-=.  That might be a good way
>>>to decide whether to advance/regress it.
>>
>>If is_iterator yields false
> 
> There is no is_iterator trait AFAIK.  And I wasn't suggesting that.
> I was suggesting something more like is_+=able and is_-=able traits.
> 
>>this is good to distinguish the rest,

Sorry, during shortening my previous mail before posting, one sentence 
got lost :) I was suggesting to add is_iterator, because if it yields 
true we should IMHO use std::advance. Only if it yields false, we should 
use your suggestion to distinguish +=able types from ++able types to use 
an efficient O(1)-implementation when possible, an O(n)-implementation 
otherwise.

>>yes. But the first question is, whether we want to enhance the 2-arg
>>version of next/prior or if we simply rename them to
>>e.g. advanced/regressed. I'd be happy with the latter. Comments?
> 
> I find those names rather awful for functions; no offense intended.

No problem, the names are not important. The important part is, whether 
we want to make the 2-arg version iterator-only.

Regards, Daniel

-- 
Daniel Frey
aixigo AG - financial solutions & technology
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eMail: daniel.frey_at_[hidden], web: http://www.aixigo.de