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How do I save objects so they inherit on reload

 [1/2] from: bobr:dprc at: 22-Jan-2001 17:40

At 08:47 AM 1/21/01 -0800, [jeff--rebol--net] wrote:
> Using parse block, it's pretty easy to make little > formatting dialects to experiment with. Someone might make > a dialect that just handles the many numerous ways to FORM, > MOLD and print dates and times.
in an unrelated (to dates) matter I would like to play with [which ever] things so that 'save and 'mold do not print object! as the datatype every time. specifically I would like to modify 'save or 'mold to be able to inherit from a named type other than object! on a load. I thought of doing a 'replace on "object!" after a 'mold but that breaks down for internal sub- object!(s) . perhaps I need to make up my own 'mold function (but can I guarantee 'save will call it?) And further, what would my own mold function look like? Would somebody show me how to write my own 'mold which, unless the object implements a particular /refinement, calls the original system one? Did I miss a lesson on dialecting? for those of you wondering if I am gonna grade the responses to this one the answer is no. I do want others to know how to grow your own 'mold (pun - ouch!) that inherits behavior from the system. I can tell some others here were trying similar things. I have been writing an internal corporate note on it and was waiting for somebody to suggest dialecting.

 [2/2] from: jeff:rebol at: 25-Jan-2001 11:32

Why modify mold? Just use delegation inheritance. REBOL [ Title: "Delegation Object inheritence" Comment: "Much the way CLOS works" Author: "Jeff Kreis" ] make-child: func [ "Make a delegating child" definition [block!] "Child object definition" 'parnt "Word that refers to parent object" /local par chl pass parent chld child parental-responsibilities ][ ;-Make sure of parent if any [not parent: get parnt not object? parent][ make error! reform [ "This is a poor excuse for a parent:" parent ] ] ;-determine what the parent can do ; (what functions) parental-responsibilities: copy [] par: next first parent foreach word par [ if any-function? get in parent word [ append parental-responsibilities word ] ] ;-determine what the child can do chl: copy [] chld: make object! definition foreach word next first chld [ if any-function? get in chld word [ append chl word ] ] ;- build the child containing ; linkage to unique parent functions child: copy [parent: none] foreach word exclude parental-responsibilities chl [ ;- build the parent calling mechanism repend child [to-set-word word 'func args: get-args get in parent word] append/only child compose [return (to-path reduce ['parent word]) (args)] ] ;- rewrite overloaded child functions ; to pass up to parent on failure foreach word intersect parental-responsibilities chl [ append child reduce [ to-set-word word 'function args: get-args fun: get in chld word [child result] ;- first class function value compose/deep [ ;- args ;- body child: func [(first :fun)] [(second :fun)] either result: child (args) [result][ (to-path reduce ['parent word]) (args) ] ] ] ] ; remake the child with new definition ;- add reference to parent and child: make chld child child/parent: get parnt child ] get-args: func [ "Get function args up to first refinement" args [any-function!] /local nargs ][ args: first :args nargs: copy [] forall args [ either word? args/1 [ append nargs args/1 ][if refinement? args/1 [return nargs]] ] nargs ] ;-- Kermit the frog example frog: make object! [ color: does [0.255.0] sound: does ["ribbit ribbit"] skin: does ["slippery"] species: does ["amphibian"] food: [ fly yummy water-bug mmmmm ] eat: func [thing][ select food thing ] animals: [ flys loves goats ignores bats hates ] likes: func [animal][ select animals animal ] ] kermit: make-child [ ;- overload what we like color: does [0.188.12] sounds: [ "Welcome to the show!" "It ain't easy being green" ["Today's number is" random 12] ] sound: func [/what] [ either block? what: pick sounds random 6 [ reform what ][what] ] skin: does ["foam"] animals: [ pig loves puppets loves humans tolerates ] likes: func [animal][ select animals animal ] food: [ hamburger gulp ] eat: func [thing][ select food thing ] ] frog ;-- Add some more food to parent append frog/food [grass yuck] print ["Does kermit eat grass?" kermit/eat 'grass] ;- save kermit the normal way save %kermit-frog.r kermit ;- see what kermit can do ; then reload kermit and ; see if kermit is still ; the same frog did: no loop 2 [ foreach [item][ [kermit/likes 'goats] [kermit/likes 'puppets] [kermit/sound] [kermit/species] [kermit/skin] [kermit/color] [kermit/eat 'fly] [kermit/eat 'hamburger] ][ prin [form to-block first item #] if pick item 2 [ prin join form next item "? " ] print item ] if not did [ unset 'kermit print "Reloading fresh kermit" ;- load the normal way kermit: do load %kermit-frog.r did: yes ] ] ;-- Does kermit still dislike grass? print ["Does kermit eat grass?" kermit/eat 'grass] { ;-- results in: Does kermit eat grass? yuck ;-(base method) kermit likes goats? ignores ; " " kermit likes puppets? loves kermit sound ribbit ribbit ; " " kermit species amphibian ; " " kermit skin foam kermit color 0.188.12 kermit eat fly? yummy ; " " kermit eat hamburger? gulp Reloading fresh kermit kermit likes goats? ignores ; " " kermit likes puppets? loves kermit sound It ain't easy being green kermit species amphibian ; " " kermit skin foam kermit color 0.188.12 kermit eat fly? yummy ; " " kermit eat hamburger? gulp Does kermit eat grass? yuck ; " " }