Structs extends, what can they all be used for ? :S

[Komaqtion]

Hello

I have now been coding with vJass for quite some time, but there are still a huge amount of different stuff which I have never used myself, such as delegate, modules, interfaces, and many of the different prefixes like [ljass]stub[/ljass] or such (That might not be the most important one, but itäs one of them XD).

Ok, so to my actual question now.
I know that structs can extend arrays to be usable as arrays, but one things I have never used here is other types of extends :S

What can be the benefits of extending other stuff, let's say [ljass]unit[/ljass] or [ljass]player[/ljass] ?

 

[kingkingyyk3]

No...

struct Human
    integer age
endstruct
struct Adult extends Human
    boolean isMarried
endstruct
struct Kids extends Human
    integer mathsMark
endstruct

When you allocate either Adult/Kids, their index will be allocated from Human, but not from the allocator in struct itself.

 

[Komaqtion]

I know how you can extend other structs, but what about other stuff (As I said) ?

 

[the Immortal]

Erm, you can't extend native types. Only other structs and "arrays", although the latter simply means the struct will act as an array and not create automatically allocate/deallocate methods.

Structs extending arrays are used when you don't use (de)allocates - when indexing objects, when willing to write your own allocator or something similar.

Structs extending other structs are used when.. well, you have a type of object that specifies another type. Like 'Kid' is a type of 'Human'. When kid extends human, and you 'create' a new kid (lolz..) you will have access to all variable members in Human and all methods and such that Human has. So calling [ljass]Kid.age[/ljass] will be perfectly fine.

 

[Komaqtion]

Oh, ok XD Sorry then...

Anyways, thanks both of you

 

[Bribe]

It would be nice to be able to extend both an array and an interface.

 

[kingkingyyk3]

For the extending the native thingy, I think you meant the dynamic array.

type PlayerArray extends player array [6]
//The methods are just like struct.
// PlayerArray.create() -> instance
// set vars[0] = Player(0)
// vars.destroy(), for destruction.
// Member :
// PlayerArray.size -> return size of array.

It is useful for structs with extended array, like AIDS struct.

struct UnitData extends array
    real array pos [3] //x,y,z
    //! runtextmacro AIDS()
endstruct
//Jasshelper does not allow this.

Solution

type RealArray extends real array [3]

struct UnitData extends array
    RealArray pos

    method AIDS_onCreate takes nothing returns nothing
        set .pos = RealArray.create()//Initialize the dynamic array.
        set .pos[0] = 0.//set the value to 0.
    endmethod

    method AIDS_onDestroy takes nothing returns nothing
        call .pos.destroy()//Destroy the dynamic array when unit is deindexed.
    endmethod
    //! runtextmacro AIDS()
endstruct