[ubernostrum]

It's more that I get tired of people declaring that indexing and length operations need to be completely and utterly and permanently forbidden and removed, and then proposing that they be replaced by operations which are equivalent to indexing and length operations.

Doing these operations on sequences of code points can be perfectly safe and correct, and in 99.99%+ of real-world cases probably will be perfectly safe and correct. My preference is for people to know what the rare failure cases are, and to teach how to watch out for and handle those cases, while the other approach is to forbid the 99.99% case to shut down the risk of mis-handling the 0.001% case.

[mjevans]

When people say they should be removed they mean primitive operations (like a standard 'length' attribute/function, or an array index operator) shouldn't exist for that type.

Just like it is better to have something like .nth(X) as a function for stepping to a numbered node, so to does a language string demand operations like .nth_printing(X) .nth_rune(X) and .nth_octet(X); to make it clear to any programmer working with that code what the intent is.

[Avernar]

Semantically equivalent yes, access time equivalent for variable width strings no. One of the reasons for Python 3's odd internal string format is because they wanted to keep indexing and have indexing be O(1). The reason why I think replacing indexing with iterators is that it removes this restriction and they could have made the internal format UTF-8 and/or easily added support for graphemes.

I prefer to have a system where 100% of the cases are valid and teaching people corner cases is not required. We all know how well teaching people about surrogate pairs went. And we're not forbidding the 99.99% case but providing an alternative way to accomplish the exact same thing. The vast majority of code uses index variables as a form of iterator anyways so it's not that big of a change.

The main reason people keep clinging to indexing strings is that's all they know. Most high level languages don't provide another way of doing it. People who program in C quickly switch from indexing to pointers into strings. Give a C programmer an iterator into strings and they'll easily handle it.