Boolexpr question

[WereElf]

Okay, I'm thinking to start using a boolexpr for 1 of my systems.
However, I have a question.
After seeing this:

function GetUnitsInRangeOfLocMatching takes real radius, location whichLocation, boolexpr filter returns group
    local group g = CreateGroup()
    call GroupEnumUnitsInRangeOfLoc(g, whichLocation, radius, filter)
    call DestroyBoolExpr(filter)
    return g
endfunction

I started wondering what happens here. More specificly with the boolexpr.

If I do something like this:

function FilterFunc takes nothing returns boolean
    return IsUnitEnemy(GetFilterUnit(), udg_FilterPlayer)
endfunction

function test takes nothing returns nothing
    set udg_FilterPlayer = GetTriggerPlayer()
    set udg_TempGroup = GetUnitsInRangeOfLocMatching(1000.00, udg_TestPoint, Condition(function FilterFunc))
    call ForGroup(//.....

Will this be usable only once since the boolexpr is destroyed or will I be able to use it as many times as I want to? And if it's the latter - why?? Isn't the boolexpr getting destroyed? Or perhaps only a "link" to the boolexpr is getting destroyed?

 

[Emm-A-]

I think, each time, that function test is run, a new boolexpr is created and destroyed after the GroupEnum.
You can test this by storing the Condition(..) expression to a variable of type boolexpr and then simply ask at the end of the function test, whether this boolexpr is null or not.

 

[WereElf]

Okay, I tested it for a while:

function FilterFunc takes nothing returns boolean
    return IsUnitEnemy(GetFilterUnit(), udg_FilterPlayer)
endfunction

function Text takes nothing returns nothing
    //call BJDebugMsg("true")
endfunction

function Trig_Test_Actions takes nothing returns nothing
    local boolexpr bexpr = Condition(function FilterFunc)
    call BJDebugMsg(I2S(GetHandleId(bexpr)))
    //set udg_FilterPlayer = GetTriggerPlayer()
    //set udg_TempPoint = Location(0,0)
    //set udg_TempGroup = GetUnitsInRangeOfLocMatching(10000.00, udg_TempPoint, bexpr)
    call DestroyBoolExpr(bexpr)
    call BJDebugMsg(I2S(GetHandleId(bexpr)))
    //call ForGroup(udg_TempGroup, function Text)
    //call DestroyGroup(udg_TempGroup)
    set bexpr = null
endfunction

Seems like the boolexprs are something like links to the function, but not quite.
When a boolexpr is not destroyed - it always has the same HandleId, but when it's destroyed - it gets a new handle id the next time.

So I guess it kind a works like a global variable - if there is one - it's using it.
If there isn't one - it's creating it.

Anyways... I kind a did some other tests, but I didn't get the results I wanted:

function FilterFunc takes nothing returns boolean
    call BJDebugMsg("ran")
    return false
endfunction

function test takes nothign returns nothing
    call Condition(FilterFunc)
endfunction

But nothing happens =/

Do boolexprs run only when calling functions that actually use them?

 

[Bribe]

Condition(function func1) == Condition(function func2) will return true. The DestroyBoolE pr thing is a relic from a time when they used to leak when you called that function.

Edit:

Do boolexprs run only when calling functions that actually use them?

You have to add a boolexpr to a trigger and call TriggerEvaluate to run it.

 

[WereElf]

So they don't leak anymore, even if I don't destroy them?

 

[Bribe]

The ones created by And, Or or Not will leak, but the ones created by Filter and Condition do not. Filter is the exact same native as Condition, but is a shorter function name.