Re: master 49e243c0c85: Avoid resizing mutation in subst-char-in-string, take two

["Mattias Engdegård" <mattias.engdegard@gmail.com>]

15 maj 2024 kl. 14.40 skrev Eli Zaretskii <eliz@gnu.org>:

> One important use case where this is not rare at all is when replacing
> characters from the same Unicode block (= "script").

It is very rare to see replacement exclusively confined to single block, except for block 0 (ASCII). Scripts, even Latin, generally transcend blocks and even planes. Text written in one script also tends to include characters from blocks not related to that script, such as symbols, spaces, combining marks, numerals etc.

The usefulness of equal-length multibyte `aset` is very small, and given how rare string mutation is in general, this makes it just not worth taking into account. Clear, simple and predictable rules are far more important.

One reason why single-character multibyte replacement (`aset`, `subst-char-in-string`, `store-substring`, most of the cl-lib functions etc) is so rare is that in the world of Unicode, a 'character' can be a sequence of scalar values (combining chars, modifiers etc) so a one-for-one value replacement is just too inflexible and limiting.