ZScript Discussion

[Graf Zahl]

I think the problem is fixed. (that is, the software side of it) Some tildes in &= ~flag assignments were missing.
Unfortunately it's a hardware problem. The key combination to produce the tilde character does not work right anymore on my computer. I guess I need a new keyboard.

Aside from that: @Nash: You GetClass checks are dead wrong! Either you test the pointer against null or don't test at all. Class types will always error out if you try to specify a non-existent class, if you have the pointer initialized it will always be valid. Running GetClass on a null pointer is a crashable offense, on the other hand.

[Major Cooke]

For this recent commits with the states, does this allow us to grab the name of the state the actor is currently in? Looks like it. I'm assuming it's a StateLabel type?

[Major Cooke]

Strangely, I couldn't get "chance" to work at all, even though the wiki is correct on that one.

That's because it's 'failchance'.

[Graf Zahl]

No. The actor is never 'in' a state. It is not possible to get a label from a state.
And the StateLabel type is not for retrieving labels but for storing state labels independently of the current actor.
It was added because the previous implementation did not have any concept of a state label at all. When it found a string in a state context it got translated within the context of the actor it was used in, causing massive problems if it was supposed to be used on another actor (e.g. the target or tracer.) By storing state labels as a dedicated type they can be passed around between functions and be resolved where they are actually needed.

[Graf Zahl]

Strangely, I couldn't get "chance" to work at all, even though the wiki is correct on that one.

That's because it's 'failchance'.

OK. Someone really needs to go through the list and review the argument names for both clarity and consistency. Any volunteers?

[Major Cooke]

I'm working on it now, but I notice there's a span of commonly used names that were changed around. I'm wondering if Gez can somehow perform a mass find and replace in the wiki...

I.e. sound 'soundname' has been changed to 'whattoplay' in a lot of places.

[Graf Zahl]

With 'reviewin' I mean to check both sides and fix the one where the names are not good. Keep in mind that for non-optional parameters this is not even relevant.

[Major Cooke]

Not to mention the first optional after the required parameters. Huh...

[Graf Zahl]

It may also make sense to change the description. This bracket madness is not helpful, especially since with named parameters they imply something that's no longer valid.
Better have the argument list as it appears in the script definitions, including the default values as-is.

[Major Cooke]

Gez? Could use your help here!

Hmm... This does make me wonder though, should we have the wiki examples as flags: 0 or flags = 0? For the sake of zscript.

[Graf Zahl]

flags: 0 is a named parameter
flags = 0 is a parameter declaration with a default value.

[Blue Shadow]

Is there currently a way to access an actor pointer's local variable? Here a simple example of what I'm trying to do:

Code: Select all

class ThingA : Actor
{
    int user_cflags;

    States
    {
    Spawn:
        SOUL A -1 Bright NoDelay
        {
            user_cflags = 16;
            A_SpawnItemEx("ThingB", 0, 64.0, 0, 0, 0, 0, 0, SXF_SETMASTER);
        }
        Stop;
    }
}

class ThingB : Actor
{
    States
    {
    Spawn:
        SOUL A -1 Bright NoDelay
        {
            if(master)
            {
                A_LogInt(master.user_cflags);
            }
        }
        Stop;
    }
}

That produces an error: "Unknown identifier 'user_cflags'".

[Graf Zahl]

Yes, but you need to cast master to a proper type that contains the variable in question. (and check if the cast was successful, in case the type did not match)
'master' is of type Actor and this type does not have a field named 'user_cflags'.

And in case you ask: If you want to do this with unrelated classes, A_GetUserVar is the only way to do it, any language that apparently can do such a thing natively is just hiding a similar function behind it.

[Major Cooke]

And in case you ask: If you want to do this with unrelated classes, A_GetUserVar is the only way to do it, any language that apparently can do such a thing natively is just hiding a similar function behind it.

That would be of immense help. This will keep things nice and sane at least and reduce all the code needed to perform it properly, especially if there's a bunch of inheriting actors that have it. It would allow overall encapsulation and dramatic reduction of bloat.

[Graf Zahl]

I won't even consider such an approach, because it's slow down the VM quite considerably. Instead of a static lookup for a member field you have to call a time consuming search function each time, and you never really can tell when it is needed and when not so you have to do it always. Don't ask me how Javascript solves this problem, but it's either slow or a memory waster.

It´s also one of the features in Javascript which drove me up walls, because it eliminates all options for compile time checks for errors and encourages sloppy coding. The result is inevitably broken code that's hard to debug.

This is also why I forced the 'override' keyword on virtual overrides, it may look redundant but is a major asset in finding scripting errors because it allows compile time checks where otherwise the program would compile but then fail at runtime with strange behavior.