Simple Unit Event Handler

[Pinzu]

I've made this simple event handler for damage detection and deaths in a spell of mine but... There is a theoretical scenario where the units alive in .gr never become 0 and therefore refresh would never happen, so how do I fix my refresh method so that alive (?) units are re-included into addUnit, and what do I have to keep in mind?

struct EventHandler 
        group        gr = CreateGroup()
        trigger      trg = null
        code         func
        unitevent    uEvent
        boolean      active = false
    
        static method addUnit takes unit u returns nothing
            if not active then
                call .refresh()
                set .active = true
            endif
            if not IsUnitInGroup(u, .gr) then
                call GroupAddUnit(.gr, u)
                call TriggerRegisterUnitEvent(.trg, u, .uEvent)
            endif
        endmethod
        
        static method refresh takes nothing returns nothing
            if .trg != null then
                call DestroyTrigger(.trg)
            endif
            set .trg = CreateTrigger()
            call TriggerAddCondition(.trg, Condition(.func))
            call GroupClear(.gr)
        endmethod
        
        static method create takes unitevent ue, code c returns EventHandler
            local thistype tmp = .allocate()
            set .uEvent = ue
            set .func = c
            return tmp
        endmethod
    endstruct

I'm not sure the above concept even works, oh unitevent and code cant be a array. What about saving them inside a hash or something and loading them that way? Right... I can't save those two in a hash, only the trigger... Forget about this.

 

[PurgeandFire]

I'm not sure if I'm following 100%, but for that scenario, you would just change your refresh method so that it: (1) destroys the trigger (2) iterates through the group (3) registers all alive units with their respective unit event/etc. (4) discards all the non-alive units from the group (GroupRemoveUnit).

Also, why are your addUnit and refresh methods static?

 

[Pinzu]

I'm not sure if I'm following 100%, but for that scenario, you would just change your refresh method so that it: (1) destroys the trigger (2) iterates through the group (3) registers all alive units with their respective unit event/etc. (4) discards all the non-alive units from the group (GroupRemoveUnit).

Also, why are your addUnit and refresh methods static?

I realised that you can't have an array of unitevent or code so the whole point of the struct above fails. ;(

For the functions, whats the difference between a static and none static method isn't all funciton calls static?

 

[edo494]

static method is such a function that has no idea of the instances of given struct(can be given one explicitly in the body), and it has sense of the struct's scope. Non-static method is such function that has known information about the instance being passed in, and also has sense of the struct's scope.

I checked, and you can indeed have unitevent arrays, code is the only disallowed type

 

[Dr Super Good]

For the functions, whats the difference between a static and none static method isn't all funciton calls static?

JASS as a language only knows "static" function calls. However vJASS pre-compiler allows for non-static methods using some trickery. By keeping all struct instances inside an array (using parallel arrays for the members) you can pass an a reference in the form of the array index to the particular struct instance. This is similar to C objects but provided in a a way more like C++.

Abstract methods can also be supported like this with a hidden "object type" member (usually called vtable or Virtual Method Table). This can be used to determine what the concrete method implementation to call is. vJASS implements this using triggers or dynamic function calls with global variables passing the function arguments.

If you want multiple instances of variables then use a struct. If you want only a single instance (eg a singleton object) then a scope or library with globals is sufficient.