[patch] : Add more symantics to sort, partial_sort, nth_element

[chris jefferson]

Paolo Carlini wrote:

>chris jefferson wrote:
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>>Exactly what it says in the title. This is the non-contraversal part
>>of the patch I sent last week. I'm still tidying up the other half.
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>Ok, I'm going to apply to v7 the patch basically as-is, besides a few
>trivial reformattings and missing std:: qualifications: passes
>regtesting, and looks basically sane. Also, v7 is for experimental code
>and we can afford a little bit of risk, for now. I will study the code
>in better detail over the next days, anyway.
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(Famous last words) I feel fairly confident about all the code from an 
algorithmic viewpoint (I've stepped through it all in a debugger), 
although it's not totally impossible (I'm fairly confident however) that 
I haven't accidentally made a slight assumption I'm not permitted to 
use. I've been finding it fairly hard to find big pieces of C++ code 
which really push the standard library to be sure.

Sorry about the qualifications...

>However, a *necessary precondition* for even envisaging merging to
>mainline this code, is documentation on top of the new helper functions
>(like __introsort_partition for moveable, __unguarded_*). I know that
>comments are also lacking on top of some HP/SGI functions but we don't
>want to follow forever those bad examples ;) We are risking maintainance
>nightmares, otherwise.
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Yes, I should have documented that.. sorry. I'm going to take the time 
to step back and do a bit of cleaning now I think, before submitting 
stable_sort / inplace_partition (which are quite intrusive).

>Also, a trivial patch replacing everywhere __is_moveable::value with
>__value is *very* welcome: user code *can* define a value macro, remember.
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It looks like I don't have to now :) But sorry, I should still have done 
this some time ago!

Chris