[REBOL] Re: Business Object Versioning
From: g:santilli:tiscalinet:it at: 5-Apr-2002 21:18
Hi Robert,
On Friday, April 05, 2002, 10:42:53 AM, you wrote:
RMM> I really would like to have object manipulation functions for 1, 2 and 3. Where
RMM> 1 can be solved by short function;-).
Well, I think you already know we can only workaround currently.
:-) I see Romano has provided some, but they're using THIRD which
has big problems:
>> obj: context [a: 'word b: func [x] [print x]]
>> obj2: context third obj
** Script Error: word has no value
** Where: context
** Near: a: word b: func [x][print x]
>> obj/a: 1
== 1
>> obj2: context third obj
** Script Error: none is missing its x argument
** Where: context
** Near: b: func [x][print x]
etc. so I'll try with a different approach. :)
add-word: func [
"Create a new object like the old one but with a word added"
object [object!]
word [word!]
] [
make object reduce [to-set-word word none]
]
rename-word: func [
"Create a new object like the old one but with a word renamed"
object [object!]
old-word [word!]
new-word [word!]
/local template
] [
template: clear [] ; not recursive, use copy if you need it to recurse
; I cannot think of a simpler way, anyone?
; (if you don't mind creating two objs you could remove then add...)
foreach word next first object [
insert tail template to-set-word either word = old-word [new-word] [word]
]
insert tail template none
template: context template
foreach word next first template [
set/any in template word get/any in object either word = new-word [old-word] [word]
]
template
]
remove-word: func [
"Create a new object like the old one but with a word removed"
object [object!]
word [word!]
/local template
] [
template: clear [] ; see above
foreach old-word next first object [
if old-word <> word [insert tail template to-set-word old-word]
]
insert tail template none
template: context template
foreach word next first template [
set/any in template word get/any in object word
]
template
]
They work as follows:
>> obj: context [a: 1 b: 2 c: 'word d: func [x] [print x]]
>> probe add-word obj 'e
make object! [
a: 1
b: 2
c: 'word
d: func [x][print x]
e: none
]
>> probe rename-word obj 'd 'e
make object! [
a: 1
b: 2
c: 'word
e: func [x][print x]
]
>> probe remove-word obj 'c
make object! [
a: 1
b: 2
d: func [x][print x]
]
HTH,
Gabriele.
--
Gabriele Santilli <[g--santilli--tiscalinet--it]> -- REBOL Programmer
Amigan -- AGI L'Aquila -- REB: http://web.tiscali.it/rebol/index.r
