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On 12/11/2025 9:14 AM EST Javier Sanchez <javiersanchezbarquero@xxxxxxxxx> 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 (<bmorris@xxxxxxxxxx>)
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
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