[QScintilla] folding quirks

[Jared Sutton]

(meant for this to be posted on the list)

Having an unfoldAll() function seems like a reasonable solution.  Is there
some way I can "officially" request such an addition?

Jared

On Wed, Feb 17, 2010 at 7:22 AM, Phil Thompson
<phil at riverbankcomputing.com>wrote:

> On Tue, 16 Feb 2010 03:50:22 -0500, Jared Sutton <jpsutton at gmail.com>
> wrote:
> > Hi All,
> >
> > For the last several years (spare time) I've been constructing a simple
> > cross-platform code editor called QSciTE using Qt4 version of
> Qscintilla2.
> >  You can find it here, in case you're interested:
> >
> > http://qscite.googlecode.com/
> >
> > First off, thanks very much for making this library available to the
> public
> > under the GPL.  It has some wonderful functionality built-in.
> >
> > I've been having some issues with code folding recently, which I believe
> to
> > have stemmed from at least one bug in Qscintilla.  I have a simple menu
> > option to enable/disable code folding.  Whenever I turn folding off, I
> want
> > any lines that are currently folded to be unfolded automatically, since
> it
> > doesn't make a whole lot of sense to have folded code that can't easily
> be
> > unfolded.  Here's my toggleFolding() function which is directly connected
> > to
> > the menu option:
> >
> > void MainWindow::toggleFolding() {
> >   QsciteEditor * doc = getCurDoc();
> >   QsciteEditor::FoldStyle state =
> > static_cast<QsciteEditor::FoldStyle>((!doc->folding()) * 5);
> >
> >   if (!state) {
> >     // unfold all code before turning off folding
> >     doc->foldAll(false);
> >   }
> >
> >   doc->setFolding(state);
> > }
> >
> > The QsciteEditor class is a child-class of Qscintilla, because I needed
> to
> > expose several functions for use with QtScript, and because I needed to
> > catch some key-presses that I needed to process specially.  As you can
> see,
> > foldAll() is only getting called just before the folding is about to be
> > turned off.  The  documentation for foldAll() states "If any lines are
> > currently folded then they are all unfolded. Otherwise all lines are
> > folded."  Now, my implementation does not take into account the
> possibility
> > that no lines were folded between the time that the folding was enabled
> and
> > disabled (which I'll expand on below), meaning that if foldAll() works as
> > documented, I should expect to see all lines get folded before the
> folding
> > is disabled.  However, even when I fold one or more lines and then turn
> off
> > folding, I find that all lines are getting folded before folding gets
> > disabled.  This seems like it's a problem with the foldAll()
> > implementation.
>
> It depends...
>
> foldAll() can only deal with what a particular lexer has set in the way of
> fold flags. I've found that lexers don't always exhibit consistent
> behaviour - some are just wrong.
>
> Both Scite and QScintilla will call foldAll() (or the Scite equivalent)
> when you shift-control-click in the fold margin. I would compare the result
> of doing this in Scite with the same lexer set and the same file being
> edited. If the result is different then it's probably a QScintilla bug. If
> it's not then it's likely to be a Scintilla bug or feature (ie. in the
> particular lexer itself).
>
> > This also brings up a few questions:
> > 1. Shouldn't setFolding() automatically unfold all lines that are
> currently
> > folded before the FoldStyle is set to NoFoldStyle?  Does anyone expect to
> > have lines folded after they disable folding?
> > 2. If the person using QsciScintilla is expected to unfold all lines that
> > were folded before turning folding off, how can he know what lines are
> > folded?  As far as I can tell, that information is private, as are the
> > functions/signals/slots that are responsible for changing a line's fold
> > state.
> >
> > So, I see these issues in the end:
> > 1. There appears to be a bug in the QsciScintilla:foldAll(bool) function.
> >  It doesn't appear to function as documented.
> > 2. In my opinion, QsciScintilla::setFolding() should either unfold
> > everything when folding is turned off, or the appropriate member
> > variables/functions/signals/slots should be changed from private to
> > protected so that developers can deal with the situation without
> resorting
> > to hacking on Qscintilla directly.
>
> How about an unfoldAll() method? (It's a shame that foldAll() was so badly
> named.) That would allow it to be used separately from setFolding(), and
> wouldn't change the behaviour of the latter for existing applications.
>
> > For what it's worth, here's my development environment:
> > Arch Linux
> > KDEmod 4.4.0
> > Qscintilla 2.4.2
> > Qt 4.6.1
> >
> > Thanks for any insight you may have.
> >
> > Jared Sutton
>
> Phil
>
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