Saving static data between class methods.

Zelgod · July 2013

Admittedly I am new-ish to Object programming and i am new to lua, i come from programming in javascript and PHP. Previously i've been using appcelerator for my projects, which is fine but sub-par for games. The forum has been helpful up to this point however im having difficulty understanding a few basic concepts that maybe someone(s) can shed some light on.

I guess the first is understanding classes despite scouring the internet and reading through articles.

What is the best practice method of creating static class variables? ex.

myclass.lua
-------
MyClass = Core.class()

function MyClass:init()
self.mystatic = 1
end

function: MyClass:someOtherMethod()
self.mystatic2 = self.mystatic2
end
------

I've seen a local table being used as storage but is this correct? should i be storing other objects in the same way?

local storage = {
myvar1 = "something"
refobj = someobject
}

My other thought is the use of metatables but honestly at this point i don't know what the best practice or simplest approaches are.

Any explanation is greatly appreciated.

atilim · July 2013

Hi,

For static variables you can use:

MyClass = Core.class()
 
MyClass.mystatic1 = 1
 
function MyClass:init()
    MyClass.mystatic2 = 1
end
 
function MyClass:someOtherMethod()
    MyClass.mystatic3 = MyClass.mystatic4
end

And use local as much as possible (Lua is global by default).

And I highly recommend Programming in Lua (2nd ed) to learn all the details of Lua 5.1.

Zelgod · July 2013

I guess my second question has now become is there a reason i cannot access a executed lua file (containing a class or module) using that method?. ex

MyClass.mystatic1 = MyExternalClass.new()

I get thrown a "attempt to index global 'MyExternalClass' (a nil value)" even though the file has not been excluded from execution (myexternalclass.lua).

Mells · July 2013

@Zelgod did you check the order of execution? ("Code dependencies", access it the same way as "Exclude from execution")

vitalitymobile · July 2013

@Zelgod and maybe name of class in myexternalclass.lua is not MyExternalClass?

Can you try this: (copy and modify from @atilim post above)

MyExternalClass= Core.class()
 
MyExternalClass.mystatic1 = 1
 
function MyExternalClass:init()
    MyExternalClass.mystatic2 = 1
end
 
function MyExternalClass:someOtherMethod()
    MyExternalClass.mystatic3 = MyExternalClass.mystatic4
end

Howdy, Stranger!

Categories

In this Discussion

Top Posters

Saving static data between class methods.

Comments

Howdy, Stranger!

Quick Links

Categories

In this Discussion

Top Posters

Saving static data between class methods.

Comments