On: Fantastic DSLs and where to find them

[zeptomu]

If your data is immutable or not is significant for program analysis and correctness, so I would say the distinction makes absolutely sense.

> Sometimes I just want to create a map and mutate its structure, and the language saying "no" is constraining me in an unpleasant way.

Languages that provide immutable data structures have often 2 variants, an immutable and mutable. Why can't you just take the mutable in that case?

I think it's more about making immutability or mutability explicit.