RE: Prototyped Procedures

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> From: Simon Coulter
> 
> Bad idea for a number of reasons.

Most of which are opinions (with which I disagree).


> 1) The only reason you get away with it is because the code is
> in-house.

Yep.  API sales.  This one matters to people who sell APIs.


> 2) Consumers only need the prototypes. They have no business looking
at
> the implementation in a properly designed interface.

If I'm debugging, I had better be able to see the source code of the
modules I'm calling.

 
> 3) If someone forgets the proper DEFINE they get the source copied
into
> the program leading to all manner of peculiar behaviour:

If someone forgets a semicolon in /free, they get all kinds of peculiar
behavior.  If someone forgets the "F" in an F-spec, they get all kinds
of peculiar behavior.


> 4) It's just plain ugly to require the consumer to decide whether they
> want the code or not.

Eye of the beholder.  Personally, I LIKE the fact that all my prototype
includes are nicely encapsulated inside a /DEFINE PROTOTYPE and a
/UNDEFINE PROTOYPE.


> /copy rpgleinc,fbnmath
> /copy rpgleinc,fbnstring
> /copy rpgleinc,fbndate
> 
> is much cleaner than forcing the consumer to remember to code
> /define prototypes
> /copy rpgleinc,fbnmath
> /copy rpgleinc,fbnstring
> /copy rpgleinc,fbndate
> /undefine prototypes

"much cleaner"?  How?


> 5) Having a separate define for each prototype name is even uglier.

Not sure who brought this up.  Not me.


On the other hand, there are real reasons to use the /DEFINE PROTOTYPE
method.  I may want to define an area in the caller and not in the
callee.  That area may need a predefined layout, such as a data
structure.  With the use of the /DEFINE, the source member can define
the data structure in both places as based, but actually define data for
it in the caller:

D MyParmDS        s                   based(pMyParmDS)
  (...) DS Subfield definitions
D MyProcedure     PR
D   pDS                           *

 /IF DEFINED(PROTOTYPE)
DwMyParmDS         s                  like(MyParmDS)
DpMyParmDS         s              *   inz(%addr(wMyParmDS))
 /EOF
 /ENDIF

In the single include technique, I'd have to hand-code those last two
lines.  Two lines may not be much, but it gets more involved with more
complex structures.  Whether you like this technique or dislike it, it
can only be done with a single include member.

Joe