Problem: :for cannot loop over a string.
Solution: Accept a string argument and iterate over its characters.
74e54fcb44
v8.2.2659 is already ported.
N/A patches for version.c:
vim-patch:8.2.2736: Vim9: for loop over string is a bit slow
Problem: Vim9: for loop over string is a bit slow.
Solution: Avoid using strlen().
175a41c13f