bug#54296: Add buffer-matching functionality

[Dmitry Gutov]

On 14.06.2022 22:17, Eli Zaretskii wrote:
> No, I proposed to use the "predicate function" method (which already
> exists).

Then the downside is "it's not readable". Or editable, really.

At this point you could say that we need to support lambas anyway (ok), 
and if people use them, we can use it for this purpose too.

But it seems to me that, by not supporting lambdas so far, over the 
couple of years since its introduction, project-kill-buffer-conditions 
has kind of proven its minimal DSL to be viable.

And if by having the 'major-mode eq' matcher we manage to avoid the use 
of lambdas in 99%+ use cases, then that's a win for usability.