[RBASE-L] - Re: TESTING FOR THE EXISTENCE OF A VARIABLE?

[A. Razzak Memon]

At 12:59 PM 3/4/2004 -0600, Steve in Memphis wrote:

Would anyone know of a way to test for the EXISTENCE of a variable?
That is, does it actually exist (been declared) regardless of its
(assigned) value, NULL or otherwise?
I thought that IFEXISTS() would do this, but, as far as I can tell,
it works pretty much like IFNULL().
Am I missing something?


Hmmmm ...

How about defining a check variable, such as vCheck (without
pre-defined data type).
Example:

SET VAR vCheck = (CTXT(.vTheVariableToChk))

Then, trap the -ERROR- variable!

If vTheVariableToChk exists, vCheck will not generate -ERROR-.
Otherwise, R:BASE will generate ERROR #2161 and ERROR #2179.
-ERROR- Unrecognized global variable in expression. (2161)
-ERROR- Expression cannot be evaluated. (2179)
Hope that helps!

Very Best R:egards,

Razzak.