Feature request: DSL support?

The nlmixr2 ecosystem of packages has a domain-specific language where a few items are intentionally different than typical R programming. Specifically, some lines should retain semicolons:

ini({
 model_parameter <- 1; label("This is my model parameter!")
})

And, the d/dt(x) operator is used to define differential equations, so it should remain together within the model:

model({
  d/dt(air_is_great) <- 100
})

These are always within a function, so it's easy to detect when this would apply vs when it would not. Would there be any appetite to include DSL functionality that could live within a package?

Start by reviewing how the formatter handles function bodies and the R constructs shown in the issue. Clarify whether support should preserve semicolons in ini() and keep d/dt(...) expressions together in model(), while leaving ordinary R formatting unchanged. Done should be defined with examples or tests for these nlmixr2 cases.