Passing a function as a variable and assigning it to an object still able to reference “self” in Lua

Question

So, I'm trying to write a function which accepts functions as its parameters and sets them as 'object' methods in Lua. Is there a specific syntax for this of which I'm not aware?

local function createObjectWithMethods(method1, method2)
    local object = {}
    object.meth1 = method1
    object:meth2 = method2 --this throws an error expecting parameters
    return object
end

Is there another way to go about this? I know that I could hardcode a method for the object, but this code needs to have functions passed as parameters, and some of those functions need to be able to reference self. Any ideas?

Answer 1

You need to write the passed-in methods without the automagic self syntax sugar.

That is you can't use:

function obj:meth1(arg1, arg2)
    -- code that uses self
end

(unless these functions are defined on some other object and being cross-applied to the new object).

Instead you need to write what the above is sugar for yourself.

function meth1(self, arg1, arg2)
    -- code that uses self
end
function meth2(self, arg1, arg2)
    -- code that uses self
end

Then you can just call the function normally and assign the functions normally.

local function createObjectWithMethods(method1, method2)
    local object = {}
    object.meth1 = method1
    object.meth2 = method2
    return object
end

createObjectWithMethods(meth1, meth2)