(j3.2006) (SC22WG5.5077) Fwd: Sorting and searching in Fortran

[Van Snyder]

On Wed, 2013-08-14 at 15:49 -0600, Dan Nagle wrote:
> Hi,
> 
> The originator of this proposal has coauthored a book on Fortran,
> and is generally well-respected in the community.
> 
> He has made a suggestion for new features for Fortran.
> I told him I would forward this to the wg5 list, so here 'tis.

I would rather spend our time doing stuff that's not trivial to do with
procedures, especially ones that have existed for fifty years.

> 
> Begin forwarded message:
> 
> > Is this what you would need as a starting point, or should I embellish them some more?
> > 
> > Regards,
> > 
> > Walter
> > 
> > ---------------------------------------------------------------------------
> > 
> > Basic sorting requirements:
> > ===========================
> > 
> > - An intrinsic function form that can be used in expressions (ala
> >   HPF 2.0 sort_up and sort_down - sans the complicated DIM argument),
> > 
> > - A 'graded' intrinsic function which returns a permutation array of
> >   integers which can be used to permute the input array (again, ala
> >   HPF grade_up and grade_down - sans the complicated DIM argument),
> > 
> > - An intrinsic subroutine form that supports 'in-place' sorts,
> > 
> > - Support INTEGER, REAL, and CHARACTER(*) types directly, e.g. without
> >   requiring a user-defined comparison function,
> > 
> > - Support both ascending and descending sorts,
> > 
> > - CHARACTER sorts support either 'default' or 'ASCII' collating
> >   sequence,
> > 
> > - Optional argument for a user-supplied comparison function for support
> >   of derived types, non-standard collating sequences, etc.
> > 
> > 
> > Basic binary search requirements:
> > =================================
> > 
> > - Intrinsic function which returns the index of the location of a value
> >   in a pre-sorted array.  If a match is not found, return 0.
> > 
> > - Support INTEGER, REAL, and CHARACTER(*) types directly, e.g. without
> >   requiring a user-defined comparison function,
> > 
> > - Support both ascending and descending sorted input arrays
> > 
> > - CHARACTER search supports either 'default' or 'ASCII' collating
> >   sequence
> > 
> > - Optional argument for a user-supplied comparison function for search
> >   of derived types, non-standard collating sequences, tolerance in
> >   floating point comparisons, etc.
>