🚀 go-pugleaf

John,

thanks for your quick answer. I've taken today's luch break
to test your remarks. I think there's been a misunderstanding.

You state the D' attribute was designed especially for the
purpose I had in mind. Well - it does not test whether a field
will be defined - it only tests whether or not a field has been
defined prior to the D' attribute reference.

This is a very useful feature, but in this case, I need to know
in advance whether or not invocation of the mapping macro
will or will not generate a given field. D' does not tell in advance,
not even in open code....

I think Roland Schiradin was closer by stating that it is impossible
to check in advance. I'll have to create my own solution.

Thanks,
Abe.
===

----- Original Message -----
From: "John R. Ehrman (408-463-3543 T/543-)" <ehrman@vnet.ibm.com>
To: <ASSEMBLER-LIST@LISTSERV.UGA.EDU>
Sent: Tuesday, October 03, 2006 8:46 PM
Subject: Look-ahead question


> The D' attribute reference will return 0 if the symbol is not
> defined, or 1 if it is; both tests are made at the position in
> the program where the attribute reference occurs. D' is meant
> to do just what you need (and was invented for that purpose).
>
> John Ehrman
>    (------------------ Referenced Note Follows --------------------)
> Date:         Tue, 3 Oct 2006 20:37:53 +0200
> From: Abe Kornelis <abe@bixoft.nl>
>
> Does anybody know of a way to tell in advance whether or not a
> specific field will be defined before its mapping macro is invoked?
>
> I have not been able to find a solution.
>
> After a field has been defined (DS or DC) I can of course use the
> D' attribute. But to my knowledge, this will not work *before* the
> field in question has been defined.
>
> I need to take action before the field is actually defined...
>
>
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