[REBOL] Re: Refinements
From: joel:neely:fedex at: 14-Nov-2002 9:48
Hi, Jan,
RDOIT! (REBOL Does Its Own Thing!)
See below...
Jan Skibinski wrote:
> Joel,
>
> > That leads me to wonder about giving each refinement an explicit
> > logical value ...
>
> I have recently come to a similar conclusion, but for a bit
> different reason: one cannot do direct logical operations on
> refinements...
>
> I ended up defining the corresponding local logical variables
> instead, so I can or- them together if needed...
Although OR is picky about the types of its arguments (for no good
reason that I can understand, as IF and EITHER allow NONE to proxy
for FALSE), you can use ANY instead as a "generalized OR", and ALL
as a "generalized AND" with either LOGIC! or NONE values ...
tester: func [/ref0 /ref1] [
print [
"ref0 was" either ref0 ["set"]["absent"] newline
"ref1 was" either ref1 ["set"]["absent"] newline
either any [ref0 ref1] [
either all [ref0 ref1] [
"both were set"
][
"one was set"
]
][
"neither was set"
]
]
]
... which behaves as ....
>> tester
ref0 was absent
ref1 was absent
neither was set
>> tester/ref0
ref0 was set
ref1 was absent
one was set
>> tester/ref1
ref0 was absent
ref1 was set
one was set
>> tester/ref0/ref1
ref0 was set
ref1 was set
both were set
HTH!
-jn-
--
----------------------------------------------------------------------
Joel Neely joelDOTneelyATfedexDOTcom 901-263-4446
