Trigger Bug?

[Sertica 18]

There is a thisList passed from a trigger to a function.  The function assumes it is an array, as it should be according to trigger documentation.  But I'm getting an error saying it is an object.

civCred = { // check player credibility as civilian
	params["_civList"];
	{
		if ("" != primaryWeapon _x) then {
			_x call joinRes;
		}
		else { if ("" != secondaryWeapon _x) then {
			_x call joinRes;
		}
		else { if ("" != handgunWeapon _x) then {
			_x call joinRes;
		}}};
	} forEach _civList;
};
area setTriggerStatements [
	"this",
	"thisList call civCred",
	"hint 'trigger off'"
];

Spoiler

 1:18:34 Error in expression <apon _x) then {
_x call joinRes;
}}};
} forEach _civList;
};
airport1 setTrigger>
 1:18:34   Error position: <forEach _civList;
};
airport1 setTrigger>
 1:18:34   Error foreach: Type Object, expected Array
 1:18:34 File H:\Storage\Win7-64\C - Home Basic\Arma 3\missions\Checkpoints.Altis\init.sqf..., line 31
 1:18:34 Error in expression <apon _x) then {
_x call joinRes;
}}};
} forEach _civList;
};
airport1 setTrigger>
 1:18:34   Error position: <forEach _civList;
};
airport1 setTrigger>
 1:18:34   Error Generic error in expression
 1:18:34 File H:\Storage\Win7-64\C - Home Basic\Arma 3\missions\Checkpoints.Altis\init.sqf..., line 31

 

[beno_83au 1362]

You're already parsing an array into the function (thisList is an array, yes). Then, by using params, you're selecting the first argument of that array (being whatever unit is first in the array) and trying to use that unit as the forEach loop. The trigger works as it should, and the easy way to fix your code is:

 

"thisList call civCred" //old
"[thisList] call civCred" //new

OR

params["_civList"]; //old
private _civList = _this; //new

 

Pick one, but not both.

[killzone_kid 1326]

forEach _this

[Sertica 18]

What is [] in an argument?  That is not documented anywhere.

[POLPOX 766]

What do you mean? That's just an empty array.

[Sertica 18]

5 hours ago, beno_83au said:

 

"thisList call civCred" //old
"[thisList] call civCred" //new

 

 

[POLPOX 766]

That's an array. Long story short, params["_civList"]; in your script picks the first element of the array, which is thislist. That's why it won't work, so use beno_83au's either solution.

[Sertica 18]

It sinks in now.  Passing it in array makes it index=0 instead of array.  SQF is very confusing coming from Java.  I thought params was like the para definition in void myMethod(Object[] myArray).

[Harzach 2505]

When in doubt, look it up!

 

https://community.bistudio.com/wiki/params

 

[Sertica 18]

That page does not explain what the elements are.

[opusfmspol 273]

Can be anything.  An array can be viewed as a list and can contain any data types, including nested arrays (lists).

 

When your trigger runs "thisList call civCred", it is passing an array (thisList) to your civCred function, which civCred receives as _this.  The elements within the array are objects in the trigger.

 

When civCred runs "params["_civList"];" on the received list _this, it is taking the first element from the list and defining it as _civList.  civCred then runs forEach on that element, not the array.  That's why you get the object error, the element is an object from the list, not the list itself.

 

But civCred needs to run the forEach on _this, the received list itself.  The forEach then cycles each element of the array.

 

Hope that's more clear.

[Harzach 2505]

4 hours ago, Sertica said:

That page does not explain what the elements are.

It literally does just that, in the first sentence.

[Sertica 18]

1 hour ago, Harzach said:

It literally does just that, in the first sentence.

I put you on my ignore list.

 

3 hours ago, opusfmspol said:

Can be anything.  An array can be viewed as a list and can contain any data types, including nested arrays (lists).

 

When your trigger runs "thisList call civCred", it is passing an array (thisList) to your civCred function, which civCred receives as _this.  The elements within the array are objects in the trigger.

 

When civCred runs "params["_civList"];" on the received list _this, it is taking the first element from the list and defining it as _civList.  civCred then runs forEach on that element, not the array.  That's why you get the object error, the element is an object from the list, not the list itself.

 

But civCred needs to run the forEach on _this, the received list itself.  The forEach then cycles each element of the array.

 

Hope that's more clear.

I have a long time programming with Java.  I know arrays.  But params is baffling.  After staring and drooling for a while I think it may have clicked.  It sees the entire function argument as 1 array.  So a single array needs to be wrapped inside another array before passing to function. 😵

[opusfmspol 273]

6 hours ago, Sertica said:

So a single array needs to be wrapped inside another array before passing to function.

 

 

 

Params command always applies the alternative syntax.  When using main syntax, it uses _this as argument for the alternative syntax.  And when _this is not an array it gets placed into an array, but if already an array it remains as is.  So yes, you wrap a single array argument when you want the given variable defined with the array intact.  When you want the array's element(s) assigned to given variable(s), you don't wrap.

 

 

 

[Dedmen 2588]

params just parses the array you give to it (or that it grabs from _this) according to the parameters you specify.

if you give it an array, and one parameter, it takes the first element of that array as parameter.

thus if you pass thisList, the _civList is the first element in the array, not the array itself.

 

This is literally explained down in the notes on the wiki page, by me, 3,5 years ago.