Re: And another crm114 script language question about 'isolate'

Bill Y <[email protected]>
Newsgroups gmane.mail.spam.crm114
Message-ID <[email protected]>
   From: "Ger Hobbelt" <[email protected]>

     isolate <default> (:var:) //

   to make sure the :var: is always there for the remainder of the code,
   even when the commandline abuser didn't specify it.


   Q: are these incantations _intended_ to be exactly the same?

     isolate (:var:)

   (Note the lack of /.../ there)

   and

     isolate <default> (:var:) //


   Verdict please? Yes (identical, and intentional) / No (not).

Yes, identical and intentional, as the default value on an ISOLATE
with no slash args is to use the prior value, and if there is no
prior value, then the null string is used.

The difference only becomes obvious if you _might_ have a prior
value (i.e. "2048") but also want a default value (say, "1024").  
Then, the results look like this:

 isolate (:var:)   --> keeps prior value, makes isolated, default value NULL
 isolate (:var:) /value/  -->  makes isolated, forces value.
 isolate (:var:) /value/ <default> --> makes isolated, applies value ONLY IF
		 NO PRIOR VALUE (and NULL is a prior value!)     

Your case (isolate <default> (:var:) // ) is a redundant case, in
that it specifies a NULL as the default value 


   yes? ... because to me it looks like they are after looking into the
   crm114 implementation details + QUICKREF accompaniment. (Hadn't
   expected that, but then documentation reading skills are apparently
   not my forte. I 'read' the code and believed

     isolate (:var:)

   wasn't doing what it actually _did_. My bad. I expected it to be
   shorthand for

     isolate (:var:) //

Nope - if a variable already has a value, ISOLATE copies it to it's own
area but keeps the value.

     - Bill Yerazunis

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