* Like in Soviet Russia:

* You don't call the GUI libraries.

* The GUI libraries call you.

Examples:

* Mouse and keyboard input

* Clock ticks and file I/O

my $window = Window.new("helloworld");
$window.add_DeleteEvent: sub ($obj, $args) { #OK
    # runs when the user deletes the window using the "close
    # window" widget in the window frame.
    Application.Quit;
};                

Application.Run;  

About Niecza:

* a recent Perl 6 implementation by Stefan O'Rear

* uses Mono or .NET, on Linux, OS X and Windows

# Translated from http://www.mono-project.com/GtkSharp:_Hello_World

constant $GTK = "gtk-sharp,Version=2.12.0.0,Culture=neutral,PublicKeyToken=35e10195dab3c99f";

constant Application = CLR::("Gtk.Application,$GTK");
constant Window      = CLR::("Gtk.Window,$GTK");
constant Button      = CLR::("Gtk.Button,$GTK");

Application.Init; 

my $window = Window.new("helloworld"); 

niecza/examples/gtk1.pl

Widgets including: AboutDialog Arrow Box Button Calendar Clipboard ComboBox Curve Dialog Drag DrawingArea FileChooserDialog Menu Printer ProgressBar Scrollbar Statusbar Timeout Toolbar TrayIcon VolumeButton Win32EmbedWidget WindowGroup and over 200 others

constant GdkCairoHelper = CLR::("Gdk.CairoHelper,$GDK");
constant GtkDrawingArea = CLR::("Gtk.DrawingArea,$GTK");
my $drawingarea = GtkDrawingArea.new;
$drawingarea.add_ExposeEvent: sub ($obj, $args) {
    my $cc = GdkCairoHelper.Create($obj.GdkWindow);  # Cairo Context
    my $windowX=0; my $windowY=0; my $windowWidth=0; my $windowHeight=0; my $windowDepth=0;
    $obj.GdkWindow.GetGeometry($windowX, $windowY, $windowWidth, $windowHeight, $windowDepth);
    $cc.SetSourceRGB(0.95.Num, 0.90.Num, 0.85.Num); $cc.Paint;  # background color
    ...           

constant GLibTimeout    = CLR::("GLib.Timeout,$GLIB"); 

GLibTimeout.Add: 60000, sub () {  # Update once per minute
    $drawingarea.QueueDrawArea(0,0,$windowSizeX,$windowSizeY);
    return True;  # meaning please continue calling this timeout handler
};                

niecza/examples/gtk-clock.pl

constant matrixRows = 20; constant matrixColumns = 10;
my @tetrominoes =  # cell coordinates relative to the "middle" cell
    [ -1,  0,  0, 0, 1, 0, 2, 0 ],  # I
    [ -1,  0,  0, 0, 1, 0, 1, 1 ],  # J
    [ -1,  1, -1, 0, 0, 0, 1, 0 ],  # L
    [ -1,  1, -1, 0, 0, 0, 0, 1 ],  # O
    [ -1,  1,  0, 1, 0, 0, 1, 0 ],  # S
    [ -1,  0,  0, 0, 0, 1, 1, 0 ],  # T
    [ -1,  0,  0, 0, 0, 1, 1, 1 ];  # Z   

my @colors =  # Copied approximately from the PC version
    [0,       0,       0      ], # 0: black background
    [0.5.Num, 0,       0      ], # 1: I maroon
    [1,       1,       1      ], # 2: J white
    [0.9.Num, 0,       0.9.Num], # 3: L dark magenta
    [0,       0,       0.6.Num], # 4: O dark blue
    [0,       0.8.Num, 0      ], # 5: S green
    [0.7.Num, 0.7.Num, 0      ], # 6: T brown
    [0,       0.8.Num, 0.8.Num]; # 7: Z dark cyan 

sub CanMovePiece($deltaX, $deltaY) {
    my $canMove = True;
    for @piece -> $x, $y {
        if $x+$pieceX+$deltaX < 0 || $x+$pieceX+$deltaX >= matrixColumns ||
           $y+$pieceY+$deltaY < 0 || $y+$pieceY+$deltaY >= matrixRows ||
           @matrix[$y+$pieceY+$deltaY][$x+$pieceX+$deltaX] != 0
        { $canMove = False; }
    }
    $canMove;
}                 

sub TryRotatePiece() {
    my @p = @piece;
    @piece .= map({ $^b, -$^a });
    if ! CanMovePiece(0, 0) {
        @piece = @p;
    }
}                 

sub KeyPressEvent($sender, $eventargs) { #OK not used
    given $eventargs.Event.Key {
        when 'Up'    { if $colorindex != 4 { TryRotatePiece() } }
        when 'Down'  { while CanMovePiece(0,1) {++$pieceY;} }
        when 'Left'  { if CanMovePiece(-1,0)   {--$pieceX;} }
        when 'Right' { if CanMovePiece( 1,0)   {++$pieceX;} }
    }
    return True;  # means this keypress is now handled
}                 

niecza/examples/gtk-tetris.pl

github.com/sorear/niecza