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native!, action!, unset!, symbol!, end!, and context!

 [1/3] from: xy:cai:msa:hinet at: 21-Jul-2004 1:47


Hi, I am curious about the difference between native! and action! I would also like to know what symbol! and unset! are used for. In REBOL 2.5.7.3.1, when I probed the variable "datatypes", I found end! and context!. Anyone has any info about the two datatypes. Thank you. Sincerely, Jerry Tsai
>> probe datatypes
[end! unset! error! datatype! context! native! action! routine! op! function! object! struct! library! port ! any-type! any-word! any-function! number! series! any-string! any-block! symbol! word! set-word! get-word ! lit-word! refinement! none! logic! integer! decimal! money! time! date! char! pair! event! tuple! bitset! string! issue! binary! file! email! url! image! tag! block! paren! path! set-path! lit-path! hash! list!] == [end! unset! error! datatype! context! native! action! routine! op! function! object! struct! library! p ort! any-type! any-word!...

 [2/3] from: g:santilli:tiscalinet:it at: 21-Jul-2004 11:54


Hi Jerry, On Tuesday, July 20, 2004, 7:47:53 PM, you wrote: xc> I am curious about the difference between native! and action! ACTION!s are "methods" for datatypes. xc> I would also like to know what symbol! and unset! are used for. UNSET! is the value that words "with no value" have. It is also the value returned by expression that "don't return anything".
>> type? get/any 'undefined-word
== unset!
>> type? print "hello"
hello == unset!
>> type? do []
== unset! SYMBOL! is an internal type. xc> In REBOL 2.5.7.3.1, when I probed the variable xc> "datatypes", I found end! and xc> context!. xc> Anyone has any info about the two datatypes. They are internal types too. CONTEXT! is the internal value that is used to represent contexts; you can think of it as being very similar to a OBJECT! (or, to be more precise, you can think of OBJECT! as being a CONTEXT! exposed to user space :). Regards, Gabriele. -- Gabriele Santilli <[g--santilli--tiscalinet--it]> -- REBOL Programmer Amiga Group Italia sez. L'Aquila --- SOON: http://www.rebol.it/

 [3/3] from: nitsch-lists::netcologne::de at: 21-Jul-2004 16:36


On Dienstag, 20. Juli 2004 19:47, xy.cai wrote:
> Hi, > > I am curious about the difference between native! and action! > > I would also like to know what symbol! and unset! are used for. >
Most are for internal use. But i highlight unset!, thats when a word has no value. its a very good typo-finder, and when you forget to initialize something. Its rarely used directly, but if you want, you can unset words with unset 'word or unset [word1 word2]
> In REBOL 2.5.7.3.1, when I probed the variable "datatypes", I found end! > and context!.
<<quoted lines omitted: 14>>
> function! object! struct! library! p > ort! any-type! any-word!...
-Volker

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