Re: :alnum: broken?

[Mattias Engdegård]

26 feb. 2020 kl. 23.38 skrev Eli Zaretskii <address@hidden>:

> Please revert these changes.  I already said that I wasn't interested in 
> making these regular expressions signal an error.

Sorry Eli, I didn't realise it was a belief strongly held. The changes have 
been reverted, of course.

But perhaps you will let me attempt to sway your opinion? I was a bit lukewarm 
to the idea myself, but the irony was not lost on me after making this very 
mistake in the implementation of code designed to find regexp errors. In short, 
the check saves time for beginners and experienced users alike, with no 
downside worth speaking about at all.

There is no way a byte-compiler warning could come close to the precision of a 
run-time check, and I speak with some modest experience on the subject. A 
compiler warning wouldn't have found my error, nor would it find common 
non-code use such as interactive search.

Initially I was worried about someone's regexp-composing code falling victim of 
a more stringent check, but Paul convinced me that this is unlikely to be an 
actual concern. Besides, we do break absolute compatibility now and then for 
good reasons, and this is one. There is also GNU grep as a precedence.