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[REBOL] Re: Obscure? You be the judge!

From: lmecir:mbox:vol:cz at: 15-May-2002 1:10

Hi Joel, <<From: "Joel Neely">> ... As Larry Wall said: Just because something is obviously happening doesn't mean that something obvious is happening. ;-) However, I'm still left with a puzzled look on my face over one aspect of this... ...
> when you 'make an 'object!, all strings, blocks and functions are > copied. > that allows for example in 'layout : > box with[append init[my-inits]] > without destroying the original in box. > also blocks, like functions, are rebound. > so [make child-proto []] gives a copy of 'dataref, not the original. > but objects are not copied, > so the 'face/feel are all the same after [make face[]]. > or in your case,
... (Oh, by the way, did you find this documented anywhere, did you just figure it out for yourself, or is there another path to enlightenment? ;-) <</Joel>> <<L>> I think, that he figured it out for himself... <</L>> <<Joel>> ... Thanks to your explanation, I have a more compact example... gub?: make object! [ data: [1] proto: make object! [ number: 0 dataref: data speak: func [] [print [number mold dataref]] ] things: [] append things make proto [number: 1] append things make proto [number: 2 dataref: data] tweak-n-speak: func [blk [block!]] [ insert data blk foreach thing things [thing/speak] ] ] ...which behaves as follows...
>> gub?/tweak-n-speak ["OK,"]
1 [1] 2 ["OK," 1] My remaining puzzlement is over this contrast: If I accept the description that (during the construction of GUB?/PROTO) GUB?/DATA is copied and GUB?/PROTO/DATAREF is set to refer to the copy, then that explains the behavior of GUB?/THING/1 . However, during the construction GUB?/THING/2 the additional spec block *also* refers to GUB?/DATA , but apparently the copy behavior does *not* occur (even though the referenced data value is still only a block). <</Joel>> <<L>> That "apparently" is incorrect. Here is a Rebol model of the MAKE PROTO behaviour: (testing appreciated) make-proto: function [ {MAKE PROTO simulation} proto [object!] spec [block!] ] [set-words object sw word value spc body] [ set-words: copy [] ; get local words from proto foreach word next first proto [ append set-words to set-word! word ] ; append all set-words from SPEC parse spec [ any [ copy sw set-word! (append set-words sw) | skip ] ] ; create a blank object with the desired local words object: blank-object set-words ; set 'self in object to refer to the object object/self: object ; copy the contents of the proto repeat i (length? first proto) - 1 [ word: pick next first proto i any-type? set/any 'value pick next second proto i any [ all [string? get/any 'value set in object word copy value] all [block? get/any 'value set in object word bind/copy value in object word] all [ function? get/any 'value spc: load mold third :value body: bind/copy second :value in object word set in object word func spc body ] any-type? set/any in object word get/any 'value ] ] ; bind the SPEC to the object bind spec in object 'self ; evaluate it spec-eval spec ; return the value of 'self as the result return get/any in object 'self ] <</L>>