Re: *LOVAL in arithmetic expression

[Reeve <rfritchman@xxxxxxxxx>]

Eric, you made my point.  If *LOVAL "depends upon the data-type it's being
assigned to..." the compiler should know, based upon the properties of the
result field, what's being requested and therefore how it should be
presented.  But a better example is *HIVAL: if I use *HIVAL to populate a
5p0 field, I get 99999.  If I use *HIVAL to populate a 5a field, I get
x'FFFFFFFF'.

The ILE RPG compiler casts ("temporarily converts") *HIVAL correctly, into
numeric or alpha, in both cases.  It seems to me that the compiler, when
evaluating an  arithmetic expression, should be able to handle *LOVAL (as
negative 9's) and *HIVAL (as positive 9's) either in assignments or in
expressions.

Here's what the V5R4 manual (page 126) says:
"Figurative constants can be specified in factor 1 and factor 2 of the
calculation specifications."

There's no mention of the use of figurative constants in expressions.
"Cast" doesn't even show up in the V5R4 ILE manual, even though there's
often (automatic) casting going on when RPG and Java talk.

Casting is a key concept of modern programming languages like C# and Java.
Boxing and unboxing, more sophisticated forms of casting, provide the
ability to treat value types (like integers, which live on the stack) as
reference types (i.e. objects, which live in heap storage).  C# handles
boxing automatically but Java requires wrapper types like Integer and Float.
If ILE RPG can't figure out how to handle *HIVAL and *LOVAL in expressions,
I'll be disappointed.  But we can't get free-form "F", "D", or "O" specs
either!

-rf


On 8/16/07, DeLong, Eric <EDeLong@xxxxxxxxxxxxxxx> wrote:
> Reeve,
>
> *LOVAL is a special value that depends on the data-type it is being
> assigned to / compared with.  In an expression, the compiler has no idea
> what type to use, so it just fails.
>
> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Reeve
> Sent: Thursday, August 16, 2007 5:12 PM
> To: RPG programming on the AS400 / iSeries
> Subject: *LOVAL in arithmetic expression
>
>
> You can do this-
>
> AoRBN = *loval;
> but not this:
>
> AoRBN = (0 - *loval);
>
> It looks like RPG doesn't understand casting or implicit conversions.  I
> know the workaround...
>
> -rf
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