Re: master 49e06183f5 1/3: Allow REQUIRE-MATCH to be a function

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> I see that the `minibuffer-completion-confirm` function completely
>> replaces the usual handling of require-match (i.e. the attempt to fix
>> the case and the prompting for confirmation).
> (You probably noticed it, but in case not -- I didn't change that code,
> I just changed the indentation.)

What I meant was that the branch you added to the `cond` overrides the
rest of the `cond` (the part you reindented).

>> Maybe this should be better documented, and also AFAICT currently
>> a `minibuffer-completion-confirm` function cannot reliably reproduce this
>> behavior by hand because it doesn't have access to `beg` and `end`.
>> I think we should make this "default behavior" more easily accessible
>> (e.g. put it into its own function and document it as something that can
>> be called from `minibuffer-completion-confirm`?).
>
> I'm pretty sure I don't understand the subtleties here, but er sure?  🧐

Understanding the subtleties can be difficult, but a good general rule
I try to follow in such cases is to provide a function that the new
function-hook can use to get back the old behavior.

IOW, arrange your code such that the user can provide a function
`mimic-t` where the resulting behavior is identical to providing `t`
(and same thing for the other supported values).
AFAICT it's currently virtually impossible (at least not without inside
knowledge of how the minibuffer.el code is written).


        Stefan