RE: Using STATIC

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> From: James Rich
>
> I am saying that returning a pointer to private storage is bad design and
> using static to fix that problem continues the bad design.  static has
> good uses.  Using it to keep your storage around so you can return a
> pointer to it is not one of them.

What do you consider "private storage"?  If you are talking about internal
state-holding variables, then certainly it's a bad idea to expose them.  On
the other hand, there are a number of times when a subprocedure might need
to return a pointer to internal storage.  These are typically called
"factory" methods, and a typical example is a connection pool.  While
certainly not as common in RPG as in OO languages, the idea of a factory
class is still perfectly valid.  Let's take Nathan Andelin's template-based
HTML generation, for example.  It would make a ton of sense to have a
factory method that loads and caches these templates, returning pointers to
them on request.

The argument might be that a pool of objects returned from a factory are not
"private storage".  While true from a "common sense" standpoint, there is no
particular attribute that automatically indicates that a given object is
"private storage" or "public storage".  It's pretty much a matter of
definition.

There are other reasons to return a pointer to private storage.  Again, I'm
talking in general terms rather than specifically in RPG terms, but it is
much easier (and faster) to compare two pointers to structures rather than
to compare the entire contents of the structure.  Let's say a method is
designed to return one of several structures.  It can either create a new
clone of the structure each time, or a pointer to an internally defined
structure.  If this method always returns a pointer to a specific internally
defined structure, a programmer may use a much more efficient pointer
comparison to determine equality.

Anyway, my point is that determining whether a given technique is "right" or
"wrong" really depends upon the implementation and the reason.

Joe