[REBOL] Re: [subject: error and trial]
From: reboler:programmer at: 5-Mar-2002 12:41
How about a new value confusing?
As in confusing? 'undefined? ==> true :)
I think I'm starting to see the difference.
>> probe new-word
** Script Error: new-word has no value
** Where: halt-view
** Near: probe new-word
>> value? 'new-word
== false
>> undefined? 'new-word
== false
Is this the answer you want for 'undefined? ? Seems that this should give 'true ?
Or is this the usage, undefined? 'word ==>true means that it is defined but has no value
? (makes the word 'undefined? confusing!)
While value? 'word ==> false means that it is not defined (and therefore cannot have
a value) ?
How does one define a new word but give it no value.
I still can't wrap my mind around the following...
>> nn: none
== none
>> probe nn
none
== none
>> value? 'nn
== true
>> undefined? 'nn
== false
>> unset 'nn
>> value? 'nn
== false
>> undefined? 'nn
== false
And how about the following. Doesn't your example just show a deficiency in using 'first?
>> set in rebol/words 'end! 1
== 1
>> probe end!
1
== 1
>> value? 'end!
== true
>> undefined? 'end!
== false
>> unset end!
>> unset 'end!
>> value? 'end
== false
>> undefined? 'end
== false
Here is another example from a fresh console session, without using 'first.
>> undefined? (in rebol/words 'end!)
== false
