Re: QSORT question

[Barbara Morris <bmorris@xxxxxxxxxx>]

Chris Pando wrote:
> Which would get deeply nested for a bunch of keys. I have a generic
> file comparison report, which needs to be able to compare 1 to n key
> fields; I do it like:
> ...
>   DoU ($I = keyCnt Or memcmpstr <> 0);
>      $I = $I + 1;
>      memcmpstr = memcmp( @bfr1@($I)
>                        : @bfr2@($I)
>                        : @fldLnB($I)
>                        );
> ...

The deep nesting can be easily avoided (see below).  The problem with
comparing by memcmp is that it doesn't compare correctly for many data
types.  For example, 
   packed data: -99999 < 12345, but x'99999d' > x'12345f'
   varying length:  'abc' < 'd', but x'0003818283??????' >
x'000184????????????'
   etc.

Here's Jon's code reduced to a single select, with no extra nesting. 
The nested select is a bit nicer, but I think this is ok too.
       select;
           // compare the year first
           when E1.Year < E2.Year;
                return -1;
           when E1.Year > E2.Year;
                return 1;

           // year is equal; compare the month next
           when E1.Month < E2.Month;
                return -1;
           when E1.Month > E2.Month;
                return 1;

           // everything is equal
                return 0;
       endsl;