Yet, Epic after following the path of deprecating UnrealScript in name of C++ and BluePrints, has decided to hire Simon Peyton Jones from Haskell fame, to design their new scripting language called Verse.
For example if a game engine keeps track of asset references, scripts could be themselves assets like any textures, levels, materials, etc and have asset references as literals in the code that the script compiler understands, allowing automatic and precise extraction of asset dependencies the scripts (and the assets that refer to those scripts) can have. This is, e.g. what Blueprint does (BP is just a visual scripting language that uses a graph with a visual editor instead of parsing text to generate an AST but the same idea applies).
I don't know much about Verse but looking at the preview I already see a type called a type called `<latent>` (async Promise?) and a `race` keyword (seems like a built-in `await Promise.all`?). I bet building these directly into the language fixes much impedance mismatch.
- Fast to compile
- Fast to run
- Memory management that doesn't destroy frame times
- Easy to embed, ideally with a small runtime
- Can target whatever ISAs and OS's that the game runs on, like consoles.
There are not dozens of languages that fit these criteria, particularly memory management, embedding, and toolchain support for consoles when you're using a proper JIT compiler and not a bytecode interpreter.
I think UE is a situation where writing a new language specifically for scripting it is absolutely the correct choice. The user base will be large enough to support it properly, and there are a lot of things that are a lot more ergonomic when the language will be built to support them after the base system is already built, instead of the other way around.
[1]: https://en.wikipedia.org/wiki/Game_Oriented_Assembly_Lisp
I strongly agree this is a superior approach to a custom language. Even better if the games industry standardized a single purpose fit scripting language
But for all intents and purposes it is a scripting language - the blocks are even converted into an AST-like intermediate representation that is then either converted to a bytecode VM or is used to generate C++ (though the BP-to-C++ conversion generates very weird code since BP allows -conceptually- multiple things to run in parallel).
But the Blueprint "front end" can be replaced with another (text based) scripting language that generated the same IR and the rest would work the same. While i haven't seen UE3's source code so i can't be 100% certain, i'd bet that the IR and VM have their roots in UnrealScript - and chances are Verse is also targeting the same IR.