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Re: use of AND and Or in presentation specs

>CLIM 1.1, Lucid 4.0.
>
>Could someone enlighten me concerning the use of AND and OR presentation
>specifiers? That is, where are they supposed to be used?
>
>We would like to be able to use them in commands ...
>
>  (define-test-window-command (BEEP-ON-A-OR-B-PRESENTATIONS)
>      ((presentation '(or a b) :gesture :select))
>    (clim:beep)
>    (format *standard-output* "~%You found an A or B."))
>
>... and/or as presentation specifiers ...
>
>  (with-output-as-presentation
>      (:stream stream :object 'bbb :type '(and a b))
>      ...)
>
>... but we get ...
>
>  >>Error: No applicable method exists for the generic-function
>  CLIM::PRESENTATION-TYPEP-METHOD when called with these arguments: 
>  (#<{Instance?} #X11B13036> NIL B A)
>
>or variations thereof. What is "{Instance?}"? 
>[We've tried '(or a b) and (or 'a 'b). Test file available on request.]
>--------------------------------------------------
> Dan Suthers           | LRDC, room 505A
> suthers+@pitt.edu     | 3939 O'Hara Street
> (412) 624-7036 office | University of Pittsburgh
> (412) 624-9149 fax    | Pittsburgh, PA 15260
>--------------------------------------------------

I'm still pretty new at CLIM (and finding the docs of little help), but
from what I understand so far, the way to do what you want would be
to define presentation command translators for a and b. Then, as the 
frame's command loop is accepting things of type 'command, both
a and b will become sensitive.

I think the 'and and 'or are better used in other cases, like
(accept '(or integer string)), rather than for trying to accept a
command.
Rick Duffy
duffy@pogo.den.mmc.com
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