From: Barry OReilly <gundaetiapo@gmail.com>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: parse-partial-sexp to stop at any depth change (and Re: Fontifying outside of region passed to registered JIT lock function)
Date: Fri, 22 Nov 2013 17:14:52 -0500 [thread overview]
Message-ID: <CAFM41H0e2nSt=iaXmmP1NVRJbOfkS5fOpDDEsf-=Ea-6Kka5Fg@mail.gmail.com> (raw)
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> insert a "display only" close-paren (with suitable coloring).
There's probably less potential to cause user confusion if it colors
existing parens rather than color parens that are not really a part of
the file content.
> 1- do add the face on the text before the beginning of the region.
> The problem there, is to make sure this face is kept up-to-date
> later on (e.g. removed if you add revert to the previous
> indentation). For that you'll want to add a jit-lock-multiline
> text-property.
I found the right colors seem to display at the right times if I:
• For initial fontification: do add the face outside the region
• For fontification after changes: rely on a new
jit-lock-after-change-extend-region-functions hook to expand the
region
Since that is working, I began investigating the performance.
One issue is my usage of parse-partial-sexp. This function's interface
doesn't make it easy to stop if there's a change of depth either up or
down, so for code simplicity I went one char at a time:
(parse-partial-sexp (point)
(1+ (point))
nil
nil
parse-state
nil)
To see if this was responsible for performance degradation, I hacked
the C implementation to allow a caller to specify "stop at a change of
depth either up or down" and used it. The performance improvement was
huge.
Now, I could write code that would do two sexp parses concurrently,
searching for a change of depth up and a change of depth down, saving
the result of the furthest parse so as to not create an O(n*n)
algorithm. Rather than complect my code in this way, what would you
think of extending the parse-partial-sexp in one of two ways:
• If TARGETDEPTH is t, stop when any change of depth occurs
• If TARGETDEPTH is a vector of integer depths, stop when any of
those depths is reached.
I figure I can't be the only one who would want to have
parse-partial-sexp stop at any change of depth. May I prepare a patch
to provide this?
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next reply other threads:[~2013-11-22 22:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-22 22:14 Barry OReilly [this message]
2013-11-23 2:01 ` parse-partial-sexp to stop at any depth change (and Re: Fontifying outside of region passed to registered JIT lock function) Stefan Monnier
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