Re: Unicode grapheme clusters

On Sat, Jan 21, 2023 at 12:37:30PM -0500, Bruce Momjian wrote:
> Well, as one of the URLs I quoted said:
>
> This is by design. wcwidth() is utterly broken. Any terminal or
> terminal application that uses it is also utterly broken. Forget
> about emoji wcwidth() doesn't even work with combining characters,
> zero width joiners, flags, and a whole bunch of other things.
>
> So, either we have to find a function in the library that will do the
> looping over the string for us, or we need to identify the special
> Unicode characters that create grapheme clusters and handle them in our
> code.

I just checked if wcswidth() would honor graphene clusters, though
wcwidth() does not, but it seems wcswidth() treats characters just like
wcwidth():

$ LANG=en_US.UTF-8 grapheme_test
wcswidth len=7

bytes_consumed=4, wcwidth len=2
bytes_consumed=4, wcwidth len=2
bytes_consumed=3, wcwidth len=0
bytes_consumed=3, wcwidth len=1
bytes_consumed=3, wcwidth len=0
bytes_consumed=4, wcwidth len=2

C test program attached. This is on Debian 11.

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Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

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