Validate Client Name

Modern code practices is to have the code read like English.
Comments should be unnecessary - they are not executable - and
executable code can change without the comment changing, so the comment
becomes out of date. (Bob Martin's lectures, articles and book "Clean
Code" describes this and other smells.)

So if WifesMothersDog, WifesFathersDog, etc. is a more understandable
way of relaying intent within the main sections of code, then use them.
They are descriptive of the process intended and encapsulate the
functionality, whereas the BIF %CHECK is a primitive, and you need
language expertise in RPG to understand it's operation. And then some
additional thought to then understand the intent while reading the code.

Also, if there is ever a need is to do more validation than %CHECK, you
have already extracted the intent and assigned a name for the
functionality, so that a maintenance programmer will be just that far
ahead to introduce the enhanced edits needed. Maybe. Because
everything is relative. No pun intended.

Wouldn't I end up with another function validateAddress identical to

validateName? In fact, isn't validateName just

encapsulating the %CHECK BIF?

Why not therefore, instead of
validatClientName ( name ); which is self documenting,

// Validate client's name.
%CHECK ( ClientName : CLIENT_NAME_CHARACTERS ); with a comment.