[Geany] remembering folding status

[Randy Kramer]

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