Re: Emacs rewrite in a maintainable language

[Tassilo Horn]

Eli Zaretskii <address@hidden> writes:

>> Yes, they are all a bit logy in general but there's one thing which
>> they (and any other editors I know of, say Vim, JEdit, gedit) do
>> orders of magnitude faster than Emacs: syntax highlighting.  Of
>> course, Emacs' font-lock is better and much more flexible because
>> it's implemented in Lisp but it's painfully slow anyway.
>
> In which major modes is font-lock "painfully slow", in your
> experience?  I only see with in C-derived languages.

Yes, C-derived modes are definitely the worst in that respect but I also
experience this problem with AUCTeX font-latex.el.  There the
fontification rules aren't that complex but there are a simply a lot of
rules.

I sometimes also have slowdowns in elisp-mode and clojure-mode but there
I think it's not the fault of font-lock but rather some minor-mode
hooking into `post-command-hook'.  I likely suspect could be
`aggressive-indent-mode' but I haven't profiled that yet because it
happens only sporadically.

So what I intended to say in the "performance matters or not" debate is
that it probably doesn’t matter too much except for evaluating Elisp.

Bye,
Tassilo