[Geany] remembering folding status

[Lex Trotman]

Hi,

Another 1.5c.  It was more fun to think about this than what I'm
supposed to be doing, especially as g++ just gave me a 75 line error
message (and all it wanted to say was I had an extra const that I
shouldn't have)

>From past experience in another system, I think the problems that Neil
is worried about are that folds are on a per line basis (confirmed by
looking at the interface), but of course any saved fold data is
garbage if the lines in the file have changed.

As Neil points out thats hard enough when only worrying about
in-memory views, its really difficult to ensure when relating saved
fold lines to an external file.  You must ensure that the file hasn't
changed in a way that invalidates the fold data.

The fold data therefore needs to save a suitable signature of the file
to decide on its validity, I guess mtime is the minimum or some MD5 or
SHA signature on the contents.

And there needs to be a way of finding the fold data for a particular
file, maybe same pathname with an added extension  would do, (eg
/home/fred/fred.cpp.fd~ ,the ~ so it would be ignored by VCS).  That
is if you don't mind such files littering your src directories.  If
its not in the same directory it gets a little bit harder still.

Once this is "solved" it would be easy to do it in Geany, just read
the fold status per line using sci_get_fold_level &
sci_get_fold_expanded and reset them later with sci_toggle_fold, oh
and save and restore what you read to file :-)

Cheers
Lex

2009/9/18 Randy Kramer <rhkramer at gmail.com>:
> On Friday 18 September 2009 04:19:04 am daspostloch at googlemail.com
> wrote:
>> where would I have to start? i'm a computational guy, so i know
>> nothing about coding for geany, graphics, gtk, scintilla, etc.
>
> I'm sure you'll get much better answers from others, but I just want to
> throw in my $0.02 (or maybe $0.03).
>
> 1. That is a feature that I'm interested in as well.  Maybe someday I'd
> be in a position to help, but for now I have my hands full trying to
> write a lexer in a language I've, for all practical purposes, never
> used (C++, nor have I "really" ever used C).
>
> 2. I'm not 100% sure about all I'll write here, but, iiuc, Geany uses
> the Scintilla widget, and things like lexing and folding are mostly
> handled by the Scintilla widget.  For at least two reasons, I'd suggest
> (and recommend) that you look into making the necessary changes at the
> Scintilla level, and thus I'd suggest you go to the Scintilla site,
> join the Scintilla mailing list, etc. The two reasons--it seems like
> the appropriate place to make the change, and, if you make the change
> there, it should be easily adaptable to geany and any one of the many
> other editors that uses Scintilla as its editing widget.
>
> Aside: I'm not clear on how much work it takes to adapt a version of
> Scintilla with new features to an existing editor like Geany--I know
> there are some differences that have to be dealt with somehow--just as
> a potential example, SciTE (the editor that Neil Hodgson has built
> based on Scintilla) uses property files to store various "property"
> settings, but Geany uses a different file and at least slightly
> different approach--iiuc, the geany files are the *.conf files, and
> filetype.* files.
>
> Neil Hodgson, the lead developer / maintainer of Scintilla is interested
> in almost the same thing--quoting from two web pages on scintilla.org:
>
> from http://www.scintilla.org/ScintillaToDo.html:
>
> "Persisting view state such as current folding into a stream or blob so
> it is easy to restore."
>
> from http://www.scintilla.org/Future.html
>
> "View state save/restore
>
> "It has been pointed out that folding does not stay when you change
> buffers in SciTE. This is because folding is stored in the view rather
> than the document to allow multiple views of one document to have
> different folding. Other applications also use the same approach as
> SciTE of having one Scintilla view object and switching any of the open
> documents into this view to make them visible. Scintilla could have a
> way of persisting all internal view state into a string/stream/blob
> that can be given back to Scintilla to ensure its view is in the same
> state as when the blob was retrieved. This feature would, for ease of
> implementation, only work where the document had not changed between
> the view state save and restore and would also not allow real
> persistence such as to a file."
>
> With respect to the final comment about not allowing "real persistence
> such as to a file"--that seems to be the limit that Neil is setting,
> but there's no technical reason that, especially once it's in a blob,
> it couldn't be stored in a file.  It is probably important that the
> document "had not changed between the view state save and restore", and
> you'd have to take steps to confirm that it hadn't (or understand the
> consequences).
>
> I'm being pretty vague here--I had thought about this somewhat (not so
> much for Scintilla/Geany, but for any editor) once upon a time.  When
> my memory clears a little, maybe I can elaborate a little more.  For,
> now, I'm just encouraging you to look at making the necessary changes
> at the Scintilla level so they are available to a wider audience.
>
> Randy Kramer
>
>
>
>
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