[open-cobol-list] Re: Redefines question

[Keisuke Nishida]

This is not that hard.  Try the attached patch.

AFAIK, this change is not standard compliant.  Don't
forget to make it optional (possibly with -std=mf),
and add a test for this change.

Cheers,
Keisuke

Roger While wrote:
> I have had several requests to support redefines whereby
> the redefining field is larger than the original field.
> Most compilers accept this (with a warning) and it is
> allowed in the standards.
> Here is an example :
>        IDENTIFICATION DIVISION.
>        PROGRAM-ID. redef.
>        ENVIRONMENT DIVISION.
>        DATA DIVISION.
>        WORKING-STORAGE SECTION.
>        01  rxwmain            pic x(16).
>        01  rxwmain2 redefines rxwmain.
>            03  filler         pic xxxx.
>            03  rxw03lev.
>                05  rxw051     pic xx.
>                05  rxw052 redefines rxw051  pic xxx.
>            03  filler         pic xxxx.
>            03  filler         pic xxxx.
>            03  filler         pic xx.
>        Procedure division.
>            display "rxwmain  " length of rxwmain.
>            display "rxwmain2 " length of rxwmain2.
>            display "rxw03lev " length of rxw03lev.
>            display "rxw051   " length of rxw051.
>            display "rxw052   " length of rxw052.
>            stop run.
>
> MF produces 2 warnings for the redefines and executes :
> rxwmain  16
> rxwmain2 17
> rxw03lev 3
> rxw051   2
> rxw052   3
>
> Notice the sizes have bubbled up. (rxw03lev and rxwmain2)
> Notice the main 01 level (rxwmain) has not changed in size BUT it's storage
> allocation is now 17.
>
> Any ideas how we can implement this?
> Looking at field.c this does not appear to be that easy.
>
> Roger
--- field.c.~1.15.~     2005-04-13 01:09:37.000000000 +0900
+++ field.c     2005-04-15 23:52:53.000000000 +0900
@@ -518,6 +518,9 @@
            {
              c->offset = c->redefines->offset;
              compute_size (c);
+             /* increase the size if redefinition is larger */
+             if (c->size > c->redefines->size)
+               size += c->size - c->redefines->size;
            }
          else
            {
@@ -629,6 +632,7 @@
        }
     }
 
+#if 0
   /* the size of redefining field should not be larger than
      the size of redefined field unless the redefined filed
      is level 01 and non-external */
@@ -638,6 +642,7 @@
          > f->redefines->size * f->redefines->occurs_max))
     cb_error_x (CB_TREE (f), _("size of '%s' larger than size of '%s'"),
                f->name, f->redefines->name);
+#endif
 
   return f->size;
 }