Carrying a variable over to a ForGroup function

[averes]

Topic says it all... how might I carry a variable over to a ForGroup call? As far as I know there's no way function to return an already made group, unless its the last created one, which in this case it wont be, in order to attach a variable. I suppose it could be done with structs? But that poses the same problem above... theres nothing in that function to attach it to?

 

[AceHart]

Use a global variable...

And, if you don't want to create one, use one of those already there:
set bj_lastCreatedUnit = <some interesting unit>
call ForGroup(...)

 

[averes]

The only problem with that is that the trigger is part of a spell which needs to be MUI. Using global variables and have multiple instances of the spell fire off make some weirrddd stuff happen .

 

[Darius34]

You could attach that group to the triggering trigger, right? I think I've done that before, with GC functions.

For the record: Is it true that globals used in ForGroup loops can cause threading errors? I once heard of a case where two ForGroup loops were going on simultaneously, each damaging separate groups of units with separate sources, and units from the second group got damaged by the source of the first group. Was that caused by the globals used?

 

[Builder Bob]

If you set a global variable just before running a ForGroup, nothing outside of the ForGroup can change that variable before the ForGroup is complete.

If you call any functions within the ForGroup, those functions will be carried out on a first come, first serve basis. When they are finished, the rest of the ForGroup will continue. After the ForGroup comes the rest of the trigger. Only when all that is complete will another trigger be executed.

It's quite easy to know if the global is being overwritten or not. There's no randomness in it. If your global is not the same before and after a ForGroup, you know it has been changed in that ForGroup. No other trigger can have done it.

 

[SFilip]

> Is it true that globals used in ForGroup loops can cause threading errors?
It's not.
Using globals with ForGroup is safe. It is not possible for two ForGroup loops to run at the same time.

 

[Flare]

The only problem with that is that the trigger is part of a spell which needs to be MUI

If there is no wait in the ForGroup callback, it's still MUI.

 

[AceHart]

> If there is no wait in the ForGroup callback, it's still MUI.

If there is, you have more serious problems than MUI...

 

[The Undaddy]

As a workaround,what I do is (because I hate transferring too much data)

function ForGroupInside takes nothing returns nothing

local unit array picked
local group g = SomeGroup()
local integer a = 0

loop
    exitwhen IsUnitGroupEmptyBJ(g)
    if FirstOfGroup(g) --matches some conditions-- then (if you want to filter some units out) 
        set picked[a] = FirstOfGroup(g)
    endif
    call GroupRemoveUnit(g,FirstOfGroup(g))
endloop 

//and now for the "for group"

loop
    set a = a - 1
    exitwhen a < 0
    //do some stuff with 'picked[a]'
endloop

endfunction

 

[Sooda]

"I hate" doesn't mean others hate it too, I find using globals way faster and better than outdated FirstOfGroup trick.

 

[The Undaddy]

"I find" doesn't mean others find it the same way too,and they might prefer using an outdated FirstOfGroup trick...

 

[TheDamien]

"I find" doesn't mean others find it the same way too,and they might prefer using an outdated FirstOfGroup trick...

Actually the speed issue is completely independent from personal opinion. Neither ForGroup nor FirstOfGroup loop are optimal. Use the filter argument of whichever GroupEnum function you are using.

 

[SerraAvenger]

As a workaround,what I do is (because I hate transferring too much data)

function ForGroupInside takes nothing returns nothing

local unit array picked
local group g = SomeGroup()
local integer a = 0

loop
    exitwhen IsUnitGroupEmptyBJ(g)
    if FirstOfGroup(g) --matches some conditions-- then (if you want to filter some units out) 
        set picked[a] = FirstOfGroup(g)
    endif
    call GroupRemoveUnit(g,FirstOfGroup(g))
endloop 

//and now for the "for group"

loop
    set a = a - 1
    exitwhen a < 0
    //do some stuff with 'picked[a]'
endloop

endfunction

please change the

local integer a = 0

loop
    exitwhen IsUnitGroupEmptyBJ(g)

to

local integer a = 0
local integer unitsInGroup = CountUnitsInGroup( g )

loop
     exitwhen unitsInGroup <= 0
     set unitsInGroup = unitsInGroup - 1 //( bad manners, I know, but...)

 

[AceHart]

Given it's already using FirstOfGroup:

loop
set u = FirstOfGroup(...)
exitwhen u == null
...
endloop


There's really no point in using that array...