Re: Could RPG become quasi-immune to level checks (was: Are level checks still useful?)

[Jeff Crosby <jlcrosby@xxxxxxxxxxxxxxxx>]

Shucks, even OPNQRYF won't get level checks.

:)



On Thu, Nov 1, 2012 at 12:53 PM, Alan Campin <alan0307d@xxxxxxxxx> wrote:

> I have been thinking the same thing for years but the whole issue is really
> mute now. Programs should be coded with SQL. All these issues vanish and we
> get so much more.
>
>
> On Thu, Nov 1, 2012 at 10:43 AM, Jeff Crosby <jlcrosby@xxxxxxxxxxxxxxxx
> > wrote:
>
> > > The reason you don't have level checks in PHP (and similar
> environments)
> > > is because they don't have hard-coded from/to positions in fields in
> the
> > > record.  When you compile an RPG program, the compiler reads the
> > > external definition, and hard-codes the from/to positions of fields in
> > > the record into the program.  You have to recompile for it to update
> > > these -- and therefore, level checks are an important safeguard.
> Without
> > > them, if the file changes, you'll end up reading (or worse, writing)
> > > incorrect data at incorrect places in the record, causing a big huge
> > mess.
> > >
> >
> > Scott's post got me thinking.
> >
> > Theoretically, could RPG be enhanced such that the from/to positions are
> > _not_ hard-coded at compile time?  Instead, based on field name (whether
> > renamed or not), the from/to positions would be established at run time.
> >  If so, one would also have to code updates properly, i.e., either  via
> > "Update RecordName %Fields(blah:blah:blah);" or making sure the O specs
> > have no end position.
> >
> > Even though I have absolutely no experience whatsoever in compiler
> writing
> > (and don't want any), I can imagine how this would fundamentally affect
> the
> > compiler.
> >
> >
> > --
> > Jeff Crosby
> > VP Information Systems
> > UniPro FoodService/Dilgard
> > P.O. Box 13369
> > Ft. Wayne, IN 46868-3369
> > 260-422-7531
> > www.dilgardfoods.com
> >
> > The opinions expressed are my own and not necessarily the opinion of my
> > company.  Unless I say so.
> > --
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