Using int was a mistake. This patch changes String, StringImpl,
StringView and StringBuilder to use size_t instead of int for lengths.
Obviously a lot of code needs to change as a result of this.
This patch adds InsertTextCommand and RemoveTextCommand.
These two commands are used to ... insert and remove text :^)
The bulk of the logic is moved into GTextDocument, and we now use the
command's redo() virtual to perform the action. Or in other words, when
you type into the text editor, we create an InsertTextCommand, push it
onto the undo stack, and call redo() on it immediately. That's how the
text gets inserted.
This makes it quite easy to implement more commands, as there is no
distinction between a redo() and the initial application.
This patch converts the undo stack from GTextDocument into GUndoStack,
and GTextDocumentUndoCommand now inherits from GCommand.
Let's turn this into a generic mechanism that can be used to implement
undo/redo in any application. :^)
With this patch, you can now assign the same GTextDocument to multiple
GTextEditor widgets via GTextEditor::set_document().
The editors have independent cursors and selection, but all changes
are shared, and immediately propagate to all editors.
This is very unoptimized and will do lots of unnecessary invalidation,
especially line re-wrapping and repainting over and over again.
This patch decouples GTextDocument and GTextDocumentLine from the line
wrapping functionality of GTextEditor.
This should basically make it possible to have multiple GTextEditors
editing the same GTextDocument. Of course, that will require a bit more
work since there's no paint invalidation yet.
The idea here is to decouple the document from the editor widget so you
could have multiple editors being views onto the same document.
This doesn't work yet, since the document and editor are coupled in
various ways still (including a per-line back-pointer to the editor.)
