🚀 go-pugleaf

I'd like to display a Composition contains Labels, and update
this display when new Labels are added.  Could someone help me
identify where is wrong and how to make it work?

Thanks a lot.

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#include <stream.h>
#include <string.h>
#include <InterViews/arraycomp.h>
#include <InterViews/character.h>
#include <InterViews/color.h>
#include <InterViews/composition.h>
#include <InterViews/deck.h>
#include <InterViews/discretion.h>
#include <InterViews/font.h>
#include <InterViews/glyph.h>
#include <InterViews/handler.h>
#include <InterViews/label.h>
#include <InterViews/listener.h>
#include <InterViews/monoglyph.h>
#include <InterViews/patch.h>
#include <InterViews/sensor.h>
#include <InterViews/strut.h>
#include <InterViews/window.h>
#include <InterViews/world.h>


class TestViewer : public MonoGlyph, public Handler {
public:
	TestViewer(Font*, Color*);
	virtual void event() {}
	void item_append(Glyph* );
	void update();

private:
	Listener*	_listener;
	Composition*	_lines;
	Patch*		_textPatch;

};

TestViewer::TestViewer(Font* f, Color* fg)
	: MonoGlyph(nil), Handler()
{
	_lines=new TBComposition(
		new Deck(),
		new ArrayCompositor(1),
		new Discretionary(
			100,
			new Character(0216, f, fg)
	       ),
		8, 5);
	_textPatch = new Patch(_lines);

	_listener = new Listener(_textPatch, this);
	_listener->sensor()->button(true, Event::any);
	_listener->sensor()->key(true);

	body(_listener);
}

void TestViewer::item_append(Glyph* g)
{	_lines->append(g);
}

void TestViewer::update()
{	_lines->repair();
	_textPatch->reallocate();

}


static PropertyData props[] = {
    { nil }
};

static OptionDesc options[] = {
    { nil }
};


int main(int argc, char** argv)
{
	World world("Test", argc, argv, options, props);
	Font* f = world.font();
	Color* fg = world.foreground();

	TestViewer* viewer = new TestViewer(f, fg);
				// the original display in unreadable
instead of blank.
				// Next 3 lines are supposed to put one line there.
/*	Glyph* g = new Label("first line", f, fg);
	viewer->item_append(g);
	viewer->update();
*/

	ApplicationWindow window(viewer);
	window.map();
	world.run();
	return 0;
}