[REBOL] Re: reduce [unset!] compose [(unset!)]
From: rotenca:telvia:it at: 23-May-2004 18:22
Hi Anton,
> >> reduce [unset! either none [][]]
> == [unset! unset]
>
> Why was the first unset! molded and the second formed?
The difference is that:
reduce [unset!]
is a block! with a word! and when you evaluate it, the word get its value,
which is the datatype! unset!.
while:
reduce [either none [][]]
is a block with an expression which, when evaluated, returns an unset value
(not the datatype unset!).
You can see also:
>> type? either none [][]
== unset!
>> type? unset!
== datatype!
> I like the above compose behaviour, it is useful, but
> why doesn't the following unset value also disappear?
>
> >> compose [(unset!)]
> == [unset!]
The same here.
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Ciao
Romano
