Re: :alnum: broken?

[Paul Eggert]

On 2/21/20 1:28 PM, Stephen Leake wrote:
> I propose this patch to help others avoid the same mistake:

Perhaps better yet would be for Emacs to do what GNU grep does:

$ grep '[:space:]'
grep: character class syntax is [[:space:]], not [:space:]
$ echo $?
2

That is, GNU grep treats a bracket expression like '[:space:]' as an 
error, since it's inevitably a typo. (POSIX does not allow this behavior 
so the diagnostic is suppressed if POSIXLY_CORRECT is set.)