Re: Partly deferred font-locking?

[Ihor Radchenko <yantar92@posteo.net>]

Eli Zaretskii <eliz@gnu.org> writes:

> My point is that when you call an expensive calculation inside
> while-no-input, you are entirely at the mercy of the code run by the
> body of while-no-input, wrt how soon after a keypress will
> while-no-input be interrupted.  And since Michael was asking precisely
> about such situations, I commented that it _might_ make Emacs less
> responsive.

I'd say that the chances are slim. Primitives like `funcall_lambda',
`if', and `when' are all calling `maybe_quit'. So, pretty much any Lisp
code will trigger interruption.

The exceptions are subroutines and external library calls, but most of
the subroutines are also sparkled with maybe_quit.

I think that it is a reasonable assumption that Emacs will not block
inside `while-no-input' in the overwhelming majority of real-world
scenarios. Exceptions are possible, but should not be a blocker - few
exceptions are much better with the current stable inflow of font-lock
performance complaints that are coming from inefficient or buggy
font-lock code in third-party packages.

-- 
Ihor Radchenko // yantar92,
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