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Comment by stefncb | Hacker News Reader

It's not necessarily about the size itself, but more about the fact that it has to go through a memory allocator and it has to be GC'd if that's applicable, while a simple integer doesn't. Copies are more involved too.

Using strings for identifiers is almost always a bad idea.

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Not something I had considered. So for example a UI component that might load 3 different versions based on a string identifier, should instead use an enum which maps to integers? I say an enum because this would preserve readability of the code.

Do you mean an API entirely internal to your application? In that case, yes, you probably want to use integers (enums), not Strings, to choose what to display.

If you are interfacing with other APIs that use Strings, it may make sense to just pass those through. For example loading files from disk or pulling up UI classes from the OS library using some String identifier or something. It's hard to say without more context.

Yes I was referring to internal APIs. Thanks

This is not true on iOS for most strings.

Why is that?

My guess is they are talking about some optimizations iOS does to make strings more performant, like interned string constants and tagged pointers. The majority of string usage probably falls under those.

Working with dynamically allocated strings, like reading from files, rendering from data bytes, working with C strings or building formatted strings, might have worse performance characteristics.

I think that's something the language does. I struggle to understand how iOS would do it.

iOS interns heavily across programming languages, and tagging and other small-string representations are available for non-C languages.

TIL!

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