[Trigger] What does this command do? :P just wondering

[Dynasti]

• Custom script: set bj_wantDestroyGroup = true

 

[Squiggy]

it destroys a unit group created via 'pick every unit in...' after doing the 'pick and do'-action
that way you don't have to assign a variable

 

[Yddohu]

You may also ask Why would I want to assign it to a variable?
Because if you don't do that and also don't use custom script that you showed, then you got leaks. Leaks makes your map laggy. That code is there to prevent that, simply.

 

[Squiggy]

Right - in that case use:

• Set unitgroup_variable = Units in blah
• Pick evey unit in unitgroup_variable and do things
• Custom script: call DestroyGroup(udg_unitgroup_variable)

 

[Dynasti]

so instead of the call DestroyGroup at the end it destroys it at the end of the lopp, right?
+ rep

 

[Yddohu]

function ForGroupBJ takes group whichGroup, code callback returns nothing
    // If the user wants the group destroyed, remember that fact and clear
    // the flag, in case it is used again in the callback.
    local boolean wantDestroy = bj_wantDestroyGroup
    set bj_wantDestroyGroup = false

    call ForGroup(whichGroup, callback)

    // If the user wants the group destroyed, do so now.
    if (wantDestroy) then
        call DestroyGroup(whichGroup)
    endif
endfunction

When you call Pick Every Unit blah blah... you are calling the jass function of ForGroupBJ

So, what this function does is actually checking the boolean variable of bj_wantDestroyGroup first. If it's true, which means you want to destroy the group, it simply destroys the group after his job is done with them.

By the way, when you call Pick Every Unit function, you set bj_wantDestroyGroup to false again. So you need to set bj_wantDestroyGroup to true everytime before you use Pick Every Unit blah blah function.