in your list, you are making 5 copies of the same object. (return value of 5
copies of the same locale)
this should be what you want.
list =: conew &> 5$ <'GameObject' NB. should return 5 distinct locales
inl_z_ =: (cocurrent@] ".@] [)"1 0
] list =. cocreate &> 5$ a:
┌─┬─┬─┬─┬─┐
│5│6│7│8│9│
└─┴─┴─┴─┴─┘
'px =: ' (, ":)"1 0 i.5
px =: 0
px =: 1
px =: 2
px =: 3
px =: 4
('px =: ' (, ":)"1 0 i.5) inl"1 0 list
0 1 2 3 4
'px' inl list
0 1 2 3 4
'px' inl {: list
4
px__go [go =. {: list
4
----- Original Message -----
From: Jon Hough <[email protected]>
To: "[email protected]" <[email protected]>
Cc:
Sent: Tuesday, June 3, 2014 8:42:36 AM
Subject: [Jprogramming] Strange Object Behaviour in J
I'm currently experimenting with OOP J. Creating objects and playing with
them.This is my code:
NB. My class def
coclass 'GameObject' px =: 0 py =: 0 pz =: 0 movex =: 3 : 'px =:
y' destroy =: codestroy
NB. lets make instances and play.
cocurrent 'base' go =: conew 'GameObject'
px__go
0 NB. returned 0, that is what I expected!
NB. move the px value...
movex__go 5
5 px__go
5 NB. again this is what I expect.
NB. create a list of GameObjects...
list =: 5 $ conew 'GameObject' NB. I don't understand the output here. list
┌─┬─┬─┬─┬─┐│2│2│2│2│2│└─┴─┴─┴─┴─┘
NB. anyway let's at least try to get a hold of one of the objects.
go =. 0{list px__go
0 NB. Wow, it worked!
movex__go 5
5 px__go
5 go2 =: 1{list px__go2
5
The very end, "px__go2" is troubling, because this object's px value is 5! The
only way this can be is if(a) 1{list and 0{list somehow point to the same
object,(b) px is a static variable.
I'm going to guess (a), but I would like to know what is going on here.
Secondly, in my object definition, I would like to have a "create" verb which
does the following:
create_go 1 4 5
this will set px to 1, py to 4 and pz to 5. I'm not sure how to do multiple
assignments in J with on function.
I think if it wasn't a class function I could do (for three arbitrary variables)
'px py pz' =: 3 NB. sets all vars to 3, not really what I want, but it's a
start.
or something like that, but for class functions I don't know how to do this.
Any help appreciated.
Regards.
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