I mean both ways should be available. It generally is reasonable to support mutable variables but immutable values should be supported as well. E.g. Scala has 2

I mean both ways should be available. It generally is reasonable to support mutable variables but immutable values should be supported as well. E.g. Scala has 2 separate keywords: var and val (the difference is you can't assign a val again once it is initialized). I want the same in C#, Python and other languages.