you can type cocreate in J console, and it will tell you that it is 18!:3.
Then look up those foreign definitions.
cocreate will create an empty numbered locale. If you look at the conew
definition, you will see that it uses cocreate to start off the process.
inl sets a locale to run code in, then evals (".) the x code string
] list =. cocreate &> 5$ a: makes 5 new objects (without anyone needing
definitions for a particular class file)
you probably want:
list =: conew &> 5$ <'GameObject'
----- Original Message -----
From: Jon Hough <[email protected]>
To: "[email protected]" <[email protected]>
Cc:
Sent: Tuesday, June 3, 2014 9:28:00 AM
Subject: Re: [Jprogramming] Strange Object Behaviour in J
Thanks for replying.
THere are a few things in your answer I don't understand unfortunately.
inl_z_ =: (cocurrent@] ".@] [)"1 0
What does the above verb do?
] list =. cocreate &> 5$ a:
What is the purpose of the above code? We already created our list of objects,
right? Also I'm not familiar with "cocreate", it is not in the OOP part of the
J guide. http://www.jsoftware.com/help/learning/25.htm
Regards
> Date: Tue, 3 Jun 2014 06:14:59 -0700
> From: [email protected]
> To: [email protected]
> Subject: Re: [Jprogramming] Strange Object Behaviour in J
>
> 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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