Re: New hook before-region-change-functions wanted

[Dmitry Gutov]

On 9/8/17 5:46 PM, Alan Mackenzie wrote:

> While it is true that this hook is not absolutely necessary,

+1

> in that the
> cache switch could be made by the first call to syntax-ppss after the
> region change, it makes the cache switch clean.  In particular, the
> cache will always be in synch with the region, and any functions which
> examine the cache at an arbitrary time (for example, jit-lock
> functions), will get the right cache.

Do we ever want the jit-lock code examining the cache contents directly?

> The mechanism will also work a
> little faster with the new hook than without it, given that changes of
> restriction are more rarely effected than syntax-ppss is called.

I don't imagine the performance difference will be in any way 
noticeable. It's just one "if".