I think starting with a familar typescript-like base language is a good approach to this. This should be familiar enough for LLMs for the most part as long as additional features can be explained in a succinct system promopt/skill.
Explaining the additional features as bits of other languages is exactly what helps LLMs:
"Dart-style constructors, Swift-style pattern matching and Strings, Trio-style async cancellation, Scala-style sealed classes"
Explaining the additional features as bits of other languages is exactly what helps LLMs:
"Dart-style constructors, Swift-style pattern matching and Strings, Trio-style async cancellation, Scala-style sealed classes"