On 01/08/2008, at 2:13 AM, Adam Glauser wrote:
If you add a *NOPASS parameter to a procedure interface, you
technically
only need to rebind the callers that use the new parameter. I'm not
sure what would happen if you removed a parameter without rebinding
the
callers.
If you add a new parameter you MUST make it optional unless you are
prepared to modify all callers and recompile.
If you add a new parameter and it is optional then you only need to
rebind those callers that use the new parameter.
If you remove a parameter from a procedure that is currently passed
by a caller nothing bad will happen. It will be put on the stack and
made available but the receiving procedure will ignore it. Subsequent
maintenance programmers might become confused but the prototype will
catch the extra parameter when they compile and it can be removed at
that time. (Still better to remove the parameter from all callers at
the same time as you modify the receiver.)
If you make a previously required parameter optional then you need to
ensure the procedure correctly handles it when not supplied but you
do not have to rebind or recompile any callers.
If you make a given parameter optional then ALL parameters that
follow it must also be optional.
If you want a new parameter to be required and still allow previous
parameters to be "not supplied" then you must make those previous
parameters omissable. Optional and omissable are not the same thing
nor are they mutually exclusive.
Regards,
Simon Coulter.
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