Re: issorted & sortrows

[Jaroslav Hajek]

On Thu, Feb 12, 2009 at 9:02 AM, John W. Eaton <address@hidden> wrote:
> On 11-Feb-2009, David Bateman wrote:
>
> | Jaroslav Hajek wrote:
> | > On Wed, Feb 11, 2009 at 7:29 PM, John W. Eaton <address@hidden> wrote:
> | >
> | >> On 11-Feb-2009, Jaroslav Hajek wrote:
> | >>
> | >> | Here, this is not so easily possible. The type of
> | >> | octave_sort<T>::compare is bool (*) (T, T), not bool (*) (const T&,
> | >> | const T&), so you'd get a type mismatch. The first form is probably
> | >> | more suitable for simple built-in types, the latter for complex ones.
> | >> | Supporting both would be possible but somewhat complicated.
> | >>
> | >> I don't see why it shouldn't use "const T&".  Doing that shouldn't
> | >> cause trouble for built-in types, and has some advantage for aggregate
> | >> types like Complex or some other class or structure that we may use
> | >> later.  I don't understand why it was ever defined to just use T.
> | >>
> | >>
> | >
> | > Apparently it was David who did it; presumably because he thought it'd
> | > be faster for the simple types. Now, because for the simple types the
> | > comparison is inlined anyway, even this vague reason is probably gone,
> | > so I'm all for changing that to const T&, const T&, presumably
> | > together with a typedef inside octave_sort (as suggested in the
> | > following mail).
> | >
> | > If you  want to do it, please go ahead, otherwise I'll do it in near 
> future.
> | >
> | Hey its a few years back that I did this so all I can say is that you
> | are probably right on the reason..
>
> OK.  I checked in the following changeset that uses some template
> magic to allow us to use "T const&" for the parameters of these
> functions if T is a class type, and to use "T" if T is not a class
> type.  It also simplifies some declarations with typedefs and removes
> the strange comparison functions for octave_value objects from the
> src/TEMPLATE-INST/Array-tc.cc file.
>
>  http://hg.savannah.gnu.org/hgweb/octave/rev/d5af326a3ede
>
> jwe
>

Just when I was compiling my own version ... :)
But yours is better - I've been long missing lo-traits.h, I just
lacked the courage to create it (my version puts the traits to
oct-sort.h). I guess maybe some of the stuff inside oct-inttypes.h can
be moved here, so I'll abandon my version.


cheers

-- 
RNDr. Jaroslav Hajek
computing expert
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz