Is A ZScript Like ACS Replacement Possible?

[22alpha22]

I have been thinking lately about ACS and how to overcome some of its inherent limitations in order to implement some features of my project and thus far I've found it easier just to have ACS call a ZScript class rather than to try to implement it directly through ACS, if that would even be possible depending on what it is I'm doing. This isn't ideal because it means I have to have at least two or more different text documents open, each using a slightly different syntax, with different limitations. I thought about trying to ditch ACS entirely for map scripting but then realized I would have recreate all of ACS's specific functions and that is just way too much.

Anyway it got me thinking, why is ACS even still a thing? ZScript came along and can do just about everything ACS can and so much more. ACS has to be pre-compiled, ZScript is plain text, ACS does not have true support for floats, doubles, or vectors, ACS can only pass scripts with a maximum of 4 arguments, the list goes on. The engine is clearly not nearly as limited as ACS is so why are we still stuck with it. For all it can do ZScript is still very unintuitive for map scripting as it was not designed to replace ACS for that, but why not? I suppose it probably doesn't matter much why not anymore as ZScript has been released into the wild for several years now so it is highly doubtful that the way it interacts with map data (sectors, lines, vertices, etc) will change. Zscript just isn't even remotely ideal for map scripting even if it does have way more potential than ACS.

How feasible would it be to create a map scripting language with all the flexibility of zscript or least the ability to overcome many of ACS's limitations while still maintaining ACS's ease of use when it comes to the actual scripting itself?

[Graf Zahl]

The main issue is that ZScript needs to be compiled at engine start, not at map start, so its code is global for the entire game session, not part of the map you play. We'd also have to export all existing ACS functions so that they remain usable. It's a lot of work, but not impossible.

[Caligari87]

Even so, that could be solved by having some boilerplate to abort / destroy an event handler or whatever if not on the correct maps.

The way I see it, there's two main functional blockers, at least from a modding perspective:

1. ACS has a delay() function which has no direct equivalent in ZScript. You can certainly achieve the same functionality with countdown variables or whatever, but it's not very user-friendly.

2. Most ACS functions are very "abstracted" for convenience. Opening a door is one function in ACS, but in ZScript requires manually setting up a thinker with obtuse undocumented methods. Again it's entirely possible to do, it's just not user friendly. Seems I'm wrong on this???!!??

Of the two, making zscript "wrappers" for the ACS functions would be relatively straightforward, if labor-intensive. I've been trying to wrap my brain around a way to easily abstract delays in ZScript (to avoid making timers manually) but haven't had much success.

[Graf Zahl]

2. Most ACS functions are very "abstracted" for convenience. Opening a door is one function in ACS, but in ZScript requires manually setting up a thinker with obtuse undocumented methods. Again it's entirely possible to do, it's just not user friendly.

All ACS specials can be called directly from ZScript and even DECORATE so this simply is not true.

[Caligari87]

... Interesting. Last time I tried to mess with altering floor heights in a map, I couldn't make it work from ZScript without considerable pain for some reason. Maybe I was missing the forest for the trees; maybe I assumed that since the ACS functions aren't exposed by name in the gzdoom.pk3 ZScript sources then they weren't available... and if that's the case I have the feeling I'm not the only one, because I've seen this idea repeated a lot by other fairly experienced people.

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This is going off on a tangent, but I presume using an ACS map function from ZScript/DECORATE requires a sector tag, yes? Is there any mechanism for those functions to directly address a sector without a tag? If not, could something be added? I'd hate to have to resort to some kind of hackery assigning a temporary tag to run an ACS function when I already have a sector reference from iterating via UDMF properties or whatever.

[Graf Zahl]

No, there are no such functions and that is quite deliberate.

[22alpha22]

All ACS specials can be called directly from ZScript and even DECORATE so this simply is not true.

How do you call an ACS specific function from ZScript? I tried using SetThingSpecial from within my monster class and GZDoom reported it as an 'unknown function'.

[Graf Zahl]

SetThingSpecial is not a special but a built-in ACS function.

[Matt]

Doesn't "<actorpointer>.special=<thing>;" work for that?

As far as functionality is concerned I can only think of complicated timed stuff that's always irritating to set up explicitly in ZScript but in ACS is just, like, "do this thing that's already set up to be animated, then wait X tics, then do this other thing".

For map-specific stuff for a single project one option is to create a custom actor that just sits there performing all of that level's level-specific ZScript scripts, maybe have the same actor class cover multiple levels and which one it is selectable using whatever parameters can be added while you're making the map. Not as elegant as having something dedicated for that one map but not terribly gross-hacky either in my view.