World: r3wp
[XML] xml related conversations
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BrianH 24-Jun-2009 [708] | OOP in a prototype-based language with function values instead of methods is different. Classes are emulated if need be, but don't always need to be. In REBOL even delegation is explicit, unlike most other prototype-based object languages. For the best maintenance use factory functions that create objects based on standard specs. Beyond that, different models are better for different tasks. Sometimes you assign function values to fields, sometimes you use class objects, sometimes class names that are looked up at runtime. |
Maxim 24-Jun-2009 [709] | I usually creat myself a new function which calls make and the object init (wether class or prototype based) if that init needs to create new inner objects, then its responsible for doing so. in your case the make-xml-object could accept an xml string and then call make-xml-object recursively for each element it finds. |
Graham 24-Jun-2009 [710] | I guess I can set the init functions to none after they've done their jobs ? |
Maxim 24-Jun-2009 [711] | not much would really be gained, but it migh trigger some GC cleanup. |
Graham 24-Jun-2009 [712x2] | i wouldn't have 100s of init functions anymore .. :) |
Using your method of creating a special context is going to screw up my obj2xml function :( | |
Sunanda 24-Jun-2009 [714] | One way to do init is as open code in the object....That only "inits" the original object, not anything MAKEd from it. But it may be useful in some cirumstances, and it does not become part of the object: o: make object! compose [print "init" (a: 99) a: 1 b: 2] |
Graham 24-Jun-2009 [715] | huh? |
BrianH 24-Jun-2009 [716] | Code in the spec block doesn't get attached to the object. |
Maxim 24-Jun-2009 [717x2] | thats another ways of doing it... instead of storing reference objects you store reference spec blocks. |
that is how its done in GLayout to assign the same setup to many styles. | |
BrianH 24-Jun-2009 [719] | The spec block is like an init function that goes away after it runs, without needing to assign none to any fields. |
Maxim 24-Jun-2009 [720] | so graham... instead of doing: ; note this is an object, context is a shortcut for make object! , like func is a shortcut for make function! addressobj: context [ number: 666 street: "styx lane" city: "pandemonium" ] pharmacy: context [ address: make addressobj [ ] ] you do: ; note this is a block addressobj: [ number: 666 street: "styx lane" city: "pandemonium" ] pharmacy: context [ address: context addressobj ] |
Graham 24-Jun-2009 [721] | I'm having to create nested objects 7 levels deep ... |
Maxim 24-Jun-2009 [722x2] | in the later, you can add code in the addressobj which will be executed everytime you create an object using it. for example: addressobj: [ number: 666 street: "styx lane" city: "pandemonium" address: rejoin [number " " street " " city] ] |
does the xml structure change a lot (lists of data, alternative or optional elements, etc) or is it really static? | |
Graham 24-Jun-2009 [724] | static largely |
Maxim 24-Jun-2009 [725x4] | cause with rebol its easy to hack stuff up using out of the box tricks..... |
something like... | |
>> probe load replace {#[object! [a: #[object! [b: #[object! [c: "%VALUE%"]]]]]]} "%VALUE%" "tadam!" make object! [ a: make object! [ b: make object! [ c: "tadam!" ] ] ] | |
;-) | |
Graham 24-Jun-2009 [729x2] | A hack. |
The XSD I'm looking at has about 30-40 complex data types | |
Maxim 24-Jun-2009 [731] | my client has a few thousand data types to cope with ;-) rebxml allows you to load that up pretty quickly...but not using the xsd obviously. its parser builds up a string and then loads it. I found it to be quite fast actually. its MUCH faster than firefox, for example. |
Graham 24-Jun-2009 [732x2] | I'm creating the XML from scratch .. and not reading it in. |
Maybe I need to use the factory way .. | |
Maxim 24-Jun-2009 [734x3] | you only need to output xml? then that is very easy. |
MUCH easier than loading it. | |
what is the source of data? | |
Graham 24-Jun-2009 [737x3] | well, output is first, reading is the next task :) |
it's all in a DB. | |
this is part of the xsd .. found an example http://stackoverflow.com/questions/790118/jaxb-types-problem | |
Maxim 24-Jun-2009 [740x2] | what I can suggest is that you build your objects like so: xml-attribute: context [ name: "someattr" value: "somevalue" ] xml-tag: context [ name: "FileID" content: [] ; a block of inner xml-tag objects attributes: [] ; a block of xml-attribute names ] then all you do is nest objects in objects, filling them up item by item recursively using DB data. |
the downside is that access either needs a wrapper func, or is done via indexes... actually attributes could be an object, since their names are mutually exclusive within an element. | |
Graham 24-Jun-2009 [742] | Let me understand this .. if I have an object that needs other objects more than 1 deep .. I can't use that to clone other objects without creating references instead of copies. |
Maxim 24-Jun-2009 [743] | you can just do a mold/all load, that will in effect copy the whole tree along with all the series too. |
Graham 24-Jun-2009 [744] | I was just thinking that. |
Maxim 24-Jun-2009 [745x2] | ex: load mold/all make object! [ a: make object! [ b: make object! [ c: "tadam!" ] ] ] will effectively create a complete duplicate of the whole object tree. |
but remember to use mold/ALL cause otherwise you end up with gibberish... | |
Graham 24-Jun-2009 [747x2] | So, I can continue to make the objects as I have been doing. But just before I use it ... I load mold/all on it to ensure I have unique objects |
ie. I load a serialized form of the object | |
Maxim 24-Jun-2009 [749] | yes. |
Graham 24-Jun-2009 [750x2] | ahh ... well problem solved :) |
seems not :( >> pharmacy: make object! [ [ name: none [ init: func [ n ][ [ self/name: n [ ] [ ] >> a: load mold/all make pharmacy [] >> probe a make object! [ name: none init: func [n][ self/name: n ] ] >> a/init "testing" ** Script Error: self has no value ** Where: init ** Near: self/name: n | |
Maxim 24-Jun-2009 [752x2] | if you have a function inside, I think you have to do it instead of load it. |
functions cannot be serialized... so they have to be bound somehow. | |
Sunanda 24-Jun-2009 [754] | Why not remove the self ? [not a metaphysical question in this context] ph: make object! [ name: none init: func [n][ name: n ] ] |
Maxim 24-Jun-2009 [755] | seems functions can be serialized, but I don't understand why the self isn't being bound to the object..that is strange. |
Graham 24-Jun-2009 [756] | because it won't work? |
Maxim 24-Jun-2009 [757] | ok, to use do, you must forget the /all. so the above, minus the /all should work with self... (it does in my tests) |
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