Question about function basics

[alleycat 28]

If I want to pack code into a function how would I do that? I have looked at the keydown functions but I am not sure of the correct syntax and what type of compile to use.

_unassigned_players = []; 
{ 
 if ((_x isKindOf "Man") and (side _x == west)) then 
 { 
	  _unassigned_players set [count _unassigned_players, _x]; 
 }; 
} forEach Allunits; 
diag_log text format["_unassigned_players: %1", count _unassigned_players];

I use this a lot and I would like to pack this into a reusable function.

[IndeedPete 1038]

You could simply put that in your init.sqf in two ways:

// Either directly put the code here:
ALY_fnc_countUnassignedPlayers = {
_unassigned_players = []; 
{ 
	 if ((_x isKindOf "Man") and (side _x == west)) then 
	 { 
		  _unassigned_players set [count _unassigned_players, _x]; 
	 }; 
} forEach Allunits; 
diag_log text format["_unassigned_players: %1", count _unassigned_players];
};

// Or you put it in an external .sqf file and then compile it:
ALY_fnc_countUnassignedPlayers = compile(preProcessFileLineNumbers "countUnassignedPlayers.sqf");

// And execute via:
call ALY_fnc_countUnassignedPlayers;

[alleycat 28]

Thanks, 2 questions about this:

1. If I call the function, will the game execute that function and wait for it to be finished or simply start it and continue with the next statement? So far I avoided functions because i was not sure how that works.

Example:

statement;

function call;

statement;

2. What is the advantage of compiling and preprocessing? Is it performane gain and does that even matter on something small as my example?

[Väinämöinen 0]

1. If you aren't suspending the script, the next statement will run in parallel with the function call. You can use the waituntil command to control that.

2. Preprocessing and compiling to a variable saves hard disk time. Everything runs from the memory. If you are calling the function frequently you should preprocess and compile your code. On a small scale it really doesn't matter.

[lappihuan 178]

The first one is not true.

As long as you use call Function the script will wait for it to return.

With spawn Function the script will continue.

[IndeedPete 1038]

Have to agree with Lappihuan. From my understanding there are three ways to execute .sqf scripts.

1. execVM - Will read in the script file then compile and then execute it line by line. Script's return value is a handle which for example can be used like this: "waitUntil {scriptDone _handle}" or "terminate _handle".

2. call - Needs the script to be preprocessed / compiled already. Executes the code and waits until it's done. Returns a value instead of a handle. When the code contains sleeps or waitUntils it must be executed within a scheduled environment. (Correct me when I'm wrong.)

3. spawn - Also needs the script to be preprocessed / compiled already. Executes the code like with execVM and returns a handle which can be used like described above.

The decision call vs. spawn/execVM is in my opinion dependant on in which environment you want to run it. Run a script containing sleep or waitUntil from a trigger or init line? Use spawn or execVM as it's not scheduled and won't wait until the script is done. Executing a function within a script (that may be executed by spawn or execVM) to calculate some value? Use call because you would want to have the result returned. Furthermore, I read somewhere spawn and execVM open new threads while call functions within the thread from where it is executed. Please, someone with better knowledge may correct me.