Re: Last steps for pretesting (font-lock-extend-region-function)

[Alan Mackenzie <acm@muc.de>]

Good afternoon, Stefan!

On Tue, 25 Apr 2006, Stefan Monnier wrote:

>>> you talk as if I wanted to remove a well-established hook in favor of
>>> some new fangled feature, whereas the font-lock-multiline property is
>>> the one that's been in Emacs since 21.1, whereas your hook is the one
>>> that's new and that you want to add to Emacs-22.

>> It has already been added.

>It hasn't been added in released code yet.

>> I'm desperately trying to stop you from taking it away again, because
>> that would make my (Emacs) life much more difficult.

>Actually no: as I've shown with my sample alternative solution, it would
>only force you to make you life simpler.

You have shown nothing of the kind.  You're in no better position to
decide what is objectively simpler than I am, since neither of is is
unbiassed in this debate.  I'm in a better position than you to know what
makes MY life simpler.  Please respect that.

>>> I think in order to justify this new hook you need to show that the
>>> pre-existing font-lock-multiline solution is not good enough in some
>>> cases.

>> I don't.  I merely need to point out that Richard specifically asked for
>> this hook to be installed.

>No: he agreed to install it after you claimed it was needed.  As a
>matter of fact, it was needed in font-lock-default-fontify-region (where
>you didn't add it) but not in font-lock-after-change-function.

He requested it.  Subject: Re: [sigra@home.se: C++-mode: Syntax
highlighting: wrong color for function identifier depending on the kind
of whitespace that follows].

RMS, 2005-02-12:
>Here's the change I was talking about.  Would someone please adapt this
>_now_ to the current sources, and install it?  Then please rename
>before-font-lock-after-change-function to
>font-lock-extend-region-function, and rename
>font-lock-run-before-after-change-hook to font-lock-extend-region?

That was a positive request, not an acquiescence.  In fact, a year
earlier in the same thread:

RMS, 2005-03-11:
>I think we should add that hook now.
>It is simple and easy to understand.
>Even if in some cases it is not a good solution,
>it is a good solution part of the time.
>That is enough reason.

It seems clear that Richard totally understood my patch.  However, he is
the best person to say what actually meant.  At the time, you saw its
purpose as being subtlely different from my intention, and we spent some
time at loggerheads because of this.  As a result of that discussion, it
became clear to me that we need a similar hook to adjust the 500-byte
chunks produced by jit.

>> When he did so, he was aware that it was called from an after-change
>> function.

>It seemed clear to him that an "extend-region" hook was a good idea and
>we all agree that it is.  But I highly doubt it that he took the time to
>understand enough to be able to judge whether placing it in
>font-lock-after-change-function was a good choice or not.  

RMS: "It is simple and easy to understand."  I think he can speak for
himself on this matter, and we should let him.

>        Stefan

-- 
Alan.