Tables always get me...

Questions
41

@Ignatz
This works. You need something that creates a unique key though, such as a physics body call. Not sure how else you could this if you weren’t using physics.

function setup()
    t={} --create two instances
    a("alive") a("doomed")
    for i,v in pairs(t) do
        print(v.status) --prints alive, doomed
        if v.status=="doomed" then v:kill() end
    end
    for i,v in pairs(t) do
        print(v.status) --prints alive
    end
end

a=class()

function a:init(status)
    self.status=status
    self.body=physics.body(CIRCLE, 10)
    t[self.body]=self --take advantage of unique memory address returned by body
end

function a:kill()
    self.body:destroy()
    t[self.body]=nil
end
42

@Ignatz on second thoughts, you can just index it with the self, you don’t need a physics body. This seems to work:

function setup()
    t={} --create two instances
    a("alive") a("doomed")
    for i,v in pairs(t) do
        print(v.status) --prints alive, doomed
        if v.status=="doomed" then v:kill() end
    end
    for i,v in pairs(t) do
        print(v.status) --prints alive
    end
end

a=class()

function a:init(status)
    self.status=status
    t[self]=self 
end

function a:kill()
    t[self]=nil
end
43

@yojimbo2000 - yes it does, but mine doesn’t

The difference, when you think about it, is that in my code, t is indexed by 1 and 2, not by the self variables. So t[self]=nil doesn’t do anything, of course. It would need to be t[1]=nil or t[2]=nil.

If I define my table like this, it works.

    local s1,s2=a("alive"), a("doomed")
    t={}
    t[s1],t[2]=s1,s2