ZScript Discussion

[Graf Zahl]

You cannot override a function in its own class - only in a subclass.

[Ed the Bat]

Can something like this be done?

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// "MyActor" has an int variable PL.
Actor t = Spawn("MyActor",pos);

let s = t;

if (s)
{
    s.PL = 1;
} 

Because this doesn't work. PL isn't recognized.

I ask because I have an array of Class<Actor>s to determine randomly which actor to spawn, and I haven't found a working solution to auto-resolve the class fully without requiring yet another cast to be around it.

Something tells me I need the list of actors to inherit from someone with the variable...

Instead of let, try this:

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MyActor s = MyActor(t);

[FelipeO_O]

What the zscript keyword "let" does? I cant remember very well.

[Ed the Bat]

Attempts to automatically choose a type for the variable being defined, I believe.

[Graf Zahl]

'let assigns the type of the right-side expression of the '=' operator to the variable, it's meant as a shorthand for stuff where otherwise some repetition would be needed or where exact knowledge of the type is not needed and it' just supposed to match a variable.
'let a = Inventory(b)' is the same as 'Inventory a = Inventory(b)'.

Other example:

let v = thing.vel; thing.VelFromAngle(); thing.vel += v;

There's no need to know what precise type this is, as long as it's compatible with the following operation.

Essentially it's equivalent to C++'s auto keyword.

[ZZYZX]

[11:40 AM] ZZYZX: I wrote this
[11:40 AM] ZZYZX: http://pastebin.com/4W9MXAnt
[11:40 AM] ZZYZX: problem is
[11:40 AM] ZZYZX: it says no function GetClassName
[11:40 AM] ZZYZX: While I'm currently looking at base.txt and actor.txt
[11:40 AM] ZZYZX: from gzdoom.pk3
[11:41 AM] ZZYZX: And see that Actor : Thinker, and Thinker : Object, and Object has native Name GetClassName();

What's wrong here?

[Fishytza]

What's the difference between this:

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if(target is "DoomPlayer")

and this:

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if(DoomPlayer(target))

?

[Rachael]

The last typecasts "target" into DoomPlayer. If the cast fails (i.e. target cannot be casted into DoomPlayer) it returns "nullptr" or false.

I am not sure exactly what conditions trigger a successful casting condition, but I would imagine any class that inherits from DoomPlayer would successfully trigger the condition specified in the if statement.

[Fishytza]

@ZZYZX

At the time of making this post, GetClassName isn't present in the latest dev build. (GZDoom g2.3pre-1072-ga37db1c)
That's probably why you're getting the error.

EDIT: ActorIterator won't do anything if the search TID is 0. What you want to do instead is use ThinkerIterator.
IE replace this

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ActorIterator ai = ActorIterator.Create(0);

with this

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ThinkerIterator ai = ThinkerIterator.Create();

Also make sure to typecast ai.Next() into Actor.

[Graf Zahl]

What's the difference between this:

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if(target is "DoomPlayer")

and this:

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if(DoomPlayer(target))

?

None. The main difference is that the first expression is a boolean result and the second one a pointer to the target type, but that only matters if you need to work with the pointer - inside an 'if' it doesn't matter.

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(target is "DoomPlayer")

is just shorthand for

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(DoomPlayer(target) != null)

The main difference is that the 'is' operator does not need a type constant to check. You can also do

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if (target is tracer.GetClass())

for example.

[Graf Zahl]

The last typecasts "target" into DoomPlayer. If the cast fails (i.e. target cannot be casted into DoomPlayer) it returns "nullptr" or false.

I am not sure exactly what conditions trigger a successful casting condition, but I would imagine any class that inherits from DoomPlayer would successfully trigger the condition specified in the if statement.

It's just like in C++. You can cast a pointer to a type if the referenced object is a subclass of that type.

[ZZYZX]

Is there any way to get the name of an object's class though? I need to somehow obtain at least RELATIVELY unique human readable data to see what actors are affected...
Also, GetClassName seems to be implemented for me here

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DEFINE_ACTION_FUNCTION(DObject, GetClassName)
{
	PARAM_SELF_PROLOGUE(DObject);
	ACTION_RETURN_INT(self->GetClass()->TypeName);
}

Might be that I'm looking at more recent code revision here than the one built at DRDTeam. Sorries in that case.

[Graf Zahl]

Just implemented yesterday: GetClassName()

[ZZYZX]

EDIT: ActorIterator won't do anything if the search TID is 0. What you want to do instead is use ThinkerIterator.
IE replace this

Code: Select all

ActorIterator ai = ActorIterator.Create(0);

with this

Code: Select all

ThinkerIterator ai = ThinkerIterator.Create();

Also make sure to typecast ai.Next() into Actor.

ThinkerIterator.Create("Actor") works, thanks.
Complete code looks like this now:

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		ThinkerIterator ti = ThinkerIterator.Create("Actor");
		Actor mo;
		while (mo = Actor(ti.Next()))
		{
			A_Log(mo.GetClassName());
		}

[Ed the Bat]

Just implemented yesterday: GetClassName()

YES! This is an absolute lifesaver! This satisfies my queries from before about how to get the name of a player's class! Thank you so much, Graf!