Re: Why you shouldn't be afraid to use VARCHAR in RPGLE

About that: "boolVal = (a = b ? 0: 1);"

Could that be implemented by "boolVal = (a = b)"? 
Am I missing something in the C-like syntax? It's been a long time since I looked at C. 

--Alan Cassidy


> On 12/11/2025 9:14 AM EST Javier Sanchez <[email protected]> wrote:
> 
> BTW, I have wondered a lot why you guys have not yet implemented the C-like
> expression as:
> boolVal = (a = b ? 0: 1);
> This is not only necessary for modern RPG but it should have been provided
> long time ago! :-)
> JS
> 
> El mié, 10 dic 2025 a las 22:04, Barbara Morris (<[email protected]>)
> escribió:
> 
> > On 2025-12-10 12:25 p.m., James H. H. Lampert via RPG400-L wrote:
> > > On 12/10/25 4:06 AM, Infodorado InfoDorado via RPG400-L wrote:
> > >> The RPG compiler is a single-pass compiler
> > >
> > > No, it can't be pure single-pass. If it were, then a program in which a
> > > variable is NOT defined in a D-spec, nor in the first C-spec in which it
> > > appears, would not compile, much less run. And it's trivially simple to
> > > construct an example of this (it took me about 2 minutes), and it
> > > compiles and runs just fine. I'd quote the source here, but it would
> > > likely be mangled beyond recognition.
> > >
> >
> > It's a single pass through the source but it gathers information that it
> > can use multiple times.
> >
> > The compiler usually allows forward-referencing, so you can code LIKE(x)
> > where x is defined later.
> >
> > But for free-form definitions, the compiler requires the parameter for
> > the data-type keywords to be defined before the keyword is seen.
> >
> >     dcl-s x char(con1);  // bad, con1 not defined yet
> >     dcl-c con1 5;
> >     dcl-s y char(con1);  // ok, con1 is defined
> >
> > Where it becomes extra fun is when you have a data structure that LOOKS
> > defined.
> >
> >     dcl-ds ds1;
> >        subf char(10);
> >     end-ds;
> >     dcl-s x char(%size(ds1));  // %size(ds1) is not defined. WHAT???
> >
> > RPG allows you to define the length of a data structure later, either
> > due to being on an I spec, possible an externally-described I spec, or
> > on a C spec.
> >
> >       C            MOVE    *blanks       ds1        50
> >
> > Almost certainly wrong columns, but you get what I mean. I'm defining
> > DS1 to have a length of 50 here, not the length of 10 that it looked
> > like it should have. Shenanigans? Yep, but upward-compatible R Us.
> >
> > We have a H-spec/CTL-OPT keyword for that: DLCOPT(*NOCHGDSLEN). With
> > that keyword, the compiler doesn't allow you to change the length of the
> > data structure like that, so it's considered defined as soon as all the
> > subfields are defined.
> >
> > --
> > Barbara
> >
> > --
> > This is the RPG programming on IBM i (RPG400-L) mailing list
> > To post a message email: [email protected]
> > To subscribe, unsubscribe, or change list options,
> > visit: https://lists.midrange.com/mailman/listinfo/rpg400-l
> > or email: [email protected]
> > Before posting, please take a moment to review the archives
> > at https://archive.midrange.com/rpg400-l.
> >
> > Please contact [email protected] for any subscription related
> > questions.
> >
> >
> -- 
> This is the RPG programming on IBM i (RPG400-L) mailing list
> To post a message email: [email protected]
> To subscribe, unsubscribe, or change list options,
> visit: https://lists.midrange.com/mailman/listinfo/rpg400-l
> or email: [email protected]
> Before posting, please take a moment to review the archives
> at https://archive.midrange.com/rpg400-l.
> 
> Please contact [email protected] for any subscription related questions.
-- 
This is the RPG programming on IBM i (RPG400-L) mailing list
To post a message email: [email protected]
To subscribe, unsubscribe, or change list options,
visit: https://lists.midrange.com/mailman/listinfo/rpg400-l
or email: [email protected]
Before posting, please take a moment to review the archives
at https://archive.midrange.com/rpg400-l.

Please contact [email protected] for any subscription related questions.