> My main gripe with immutability is that making updated data requires building a full copy of the data again with the changes. Conceptually yes, but the imple

> My main gripe with immutability is that making updated data requires building a full copy of the data again with the changes. Conceptually yes, but the implementation doesn't always necessarily need to work that way under the hood: https://www.roc-lang.org/functional#opportunistic-mutation https://www.roc-lang.org/functional#opportunistic-mutation