RE: RPG - conversion vs re-write

["Hans Boldt" <hboldt@xxxxxxxxxxxx>]

Bob Cozzi <BobCozzi@ibm.net> wrote
>Okay, here's some code that saves absolutely nothing, but is more
>English-like that %NULLID(ddd)=*ON
>
>
>     D IsNULL          PR             1S 0
>     D   TestDate                      L   Const
>
>     PIsNULL           B                   Export
>     D IsNull          PI             1S 0
>     D  TestDate                       L   Const
>     C                   Return    (%NULLID(TestDate)=*ON)
>     PIsNULL           E
>
>Using this procedure, you can then do this in Calcs
>
>C                  If            IsNull(MyDateFld)
>C                  /*  do your null-date routine here */
>C                  endif
>
>
>This would be the same as:
>
>C                  If            %NullID(MyDateFld)=*ON
>C                  /*  do your null-date routine here */
>C                  endif
>
>
>Now, I suppose the thing that might byte me is the return type on the
>procedures. I used a 1-digit signed numeric. I don't know if Indicators can
>automatically be cast to zoned decimals, so if it doesn't work, do a Z-ADD
>deal right before the return, or similar.


Bob:  Have you actually tried coding this?  Here's a hint:  It won't
compile!  The expression in the IF statement must return an indicator
value.  Your procedure "IsNULL" returns a numeric value.

Here's another hint:  Since the built-in function %NULLIND returns an
indicator value, you just have to code:

          C                 IF        %NULLIND(MyDateField)
          C                   /* stuff */
          C                 ENDIF

(This is described on page 342 of the RPG Reference Manual.)

Cheers!  Hans

Hans Boldt, ILE RPG Development, IBM Toronto Lab, hboldt@vnet.ibm.com
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