function CountUnitsInGroup takes group g returns integer
    // 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

    set bj_groupCountUnits = 0
    call ForGroup(g, function CountUnitsInGroupEnum)

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

function CountUnitsInGroupEnum takes nothing returns nothing
    set bj_groupCountUnits = bj_groupCountUnits + 1
endfunction

function GroupPickRandomUnit takes group whichGroup returns unit
    // 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

    set bj_groupRandomConsidered = 0
    set bj_groupRandomCurrentPick = null
    call ForGroup(whichGroup, function GroupPickRandomUnitEnum)

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

function GroupPickRandomUnitEnum takes nothing returns nothing
    set bj_groupRandomConsidered = bj_groupRandomConsidered + 1
    if (GetRandomInt(1,bj_groupRandomConsidered) == 1) then
        set bj_groupRandomCurrentPick = GetEnumUnit()
    endif
endfunction