Re: Change in files.el

[Dmitry Gutov <dgutov@yandex.ru>]

On 28.01.2017 17:57, Eli Zaretskii wrote:

> These sound minor to me (and the last two are also possible without
> the requirement, AFAIU).  By contrast, insisting on a function value
> instead of the default nil forces me to go through at least one more
> level of indirection when I need to understand what happens in a
> function that references such variables, which sounds like a more
> serious trouble from my POV.

It's just one more level of indirection. We routinely deal with dozens 
of them. This above rule should just be adhered consistently, and the 
indirection won't be a surprise every time.

On the plus side, you might get a smaller function that calls the 
-default one, because some code will be extracted.

Finally, the default value of save-some-buffers-default-predicate can be 
#'ignore or #'identity (it's either this, or the previous paragraph, I'm 
not familiar with the code enough to be sure).

> I was up to my neck in this when I
> needed to document all the various optional behaviors implemented in
> isearch.el, and bumped into similar issues several times elsewhere.

isearch.el and etags.el have more egregious problems, such as extensive 
use of dynamic bindings.