Re: regular expressions that match nothing

[Alan Mackenzie <acm@muc.de>]

Hello, Mattias.

On Wed, May 15, 2019 at 18:21:07 +0200, Mattias Engdegård wrote:
> tis 2019-05-14 klockan 15:41 -0400 skrev Stefan Monnier:

> > Yes, please.  I'd recommend a `regexp-` prefix for it.

> Well, since you asked so nicely!

> > [ And I'll carefully avoid having an opinion on the rest of the name.
> > ]

> The correct name is obviously something like `regexp-empty', but I have
> to concede that it might be misinterpreted. The attached patch uses
> `regexp-unmatchable' which is reasonably descriptive. Better
> suggestions are welcome.

I think regexp-unmatchable is too much of a mouthful.  It is more
difficult to type that a\\` (or whatever), even after having to think
where the seldom used keys are on the keyboard.  Also it is difficult to
spell.  is it unmatchable or unmatcheable?

I would suggest re-nomatch (or possibly nomatch-re), which is just 10
characters, as opposed to your suggestion which is 18.  Quite possibly,
re-nomatch is easier to type than a\\` (or whatever).

This ease of typing is important, because it encourages hackers to use
it rather than typing out the shorter thing.

-- 
Alan Mackenzie (Nuremberg, Germany).