Pure Regular Expression Engines and Literal Clusters

[Richard Wordingham via Unicode]

On Thu, 10 Oct 2019 15:23:00 -0700
Markus Scherer via Unicode <unicode at unicode.org> wrote:

> [c \q{ch}]h should work like (ch|c)h. Note that the order matters in
> the alternation -- so this works equivalently if longer strings are
> sorted first.

Thanks for answering the question.

Does conformance UTS#18 to level 2 mandate the choice of matching
substring? This would appear to prohibit compliance to POSIX rules,
where the length of overall match counts.

Richard.