Comment by bastawhiz
4 days ago
> all optimizations from compiled / statically typed / lower level languages
Mutable strings are totally possible (and not even especially hard) in compiled, statically typed, and lower-level languages. They're just not especially performant, and are sometimes a footgun.
> all those complicated features right from the start
Arguably, mutable strings are the more complicated feature. Removing them by default simplifies the language, or at least forces you to go out of your way to find the complexity.
Its not about possible / not possible its about what the language does by default and how language syntax changes to switch between different variants of strings
> They're just not especially performant
What? Mutable strings are more performant generally. Sometimes immutability allows you to use high level algorithms that provide better performance, but most code doesn't take advantage of that.
Not in general. Immutable strings can be deduplicated, leading to a different performance tradeoff that is often quite good. This is mentioned in TFA.
It’s worth noting that C++ standard libraries have mostly moved away from copy-on-write strings, due to their poor performance in multithreaded scenarios. And JavaScript engines have ended up adding a bunch of optimizations that simulate mutable strings in certain common scenarios. It depends on what the code in question is doing, and I think the ideal scenario is to allow both in different contexts as long as they can be kept distinct.
Mutable strings can be duplicated too. You can use reference counting, or borrow checking in Rust.
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