I certainly don't want to pay for a syscall to do string encoding. Also, a lot of the time the problem isn't that people are using fundamentally incompatible s

I certainly don't want to pay for a syscall to do string encoding. Also, a lot of the time the problem isn't that people are using fundamentally incompatible string libraries, but that there isn't one correct answer to the question they're asking and they chose different ways to convert the question into code. A reasonable question to ask is "How many extended grapheme clusters are in this string?" The answer is "It depends on what font you plan to use to render it." Not great! Some programmers would still like to e.g. write a reverse() function that returns ":regional_indicator_f::regional_indicator_r:" unmodified (because it is the French flag emoji) and returns ":regional_indicator_i::regional_indicator_h:" when given ":regional_indicator_h::regional_indicator_i:". If such people want to avoid having nonsensical behavior in their programs, the only solution available is to decide what domain the program should work on and actually deal with the complexity of the domain chosen.