implement Dialog; include "sys.m";	sys: Sys; include "draw.m";	draw: Draw;	Screen, Rect, Point: import draw; include "tk.m";	tk: Tk;	Toplevel: import tk; include "tkclient.m";	tkclient: Tkclient; include "dialog.m"; init(): string{	sys = load Sys Sys->PATH;	draw = load Draw Draw->PATH;	tk = load Tk Tk->PATH;	tkclient = load Tkclient Tkclient->PATH;	tkclient->init();	return nil;} STEP: con 20; ## find upper left corner for subsidiary child window (always at constant# position relative to parent)#localgeom(im: ref Draw->Image): string{	if (im == nil)		return nil; 	return sys->sprint("-x %d -y %d", im.r.min.x+STEP, im.r.min.y+STEP);} centre(t: ref Toplevel){	org: Point;	org.x = t.image.screen.image.r.dx() / 2 - t.image.r.dx() / 2;	org.y = t.image.screen.image.r.dy() / 3 - t.image.r.dy() / 2;	if (org.y < 0)		org.y = 0;	cmd(t, ". configure -x " + string org.x + " -y " + string org.y);} tkcmds(top: ref Tk->Toplevel, a: array of string){	n := len a;	for(i := 0; i < n; i++)		tk->cmd(top, a[i]);} dialog_config := array[] of {	"label .top.ico",	"label .top.msg",	"frame .top -relief raised -bd 1",	"frame .bot -relief raised -bd 1",	"pack .top.ico -side left -padx 10 -pady 10",	"pack .top.msg -side left -expand 1 -fill both -padx 10 -pady 10",	"pack .Wm_t .top .bot -side top -fill both",	"focus ."}; prompt(ctxt: ref Draw->Context,	parent: ref Draw->Image,	ico: string,	title:string,	msg: string,	dflt: int,	labs : list of string): int{	where := localgeom(parent); 	(t, tc) := tkclient->toplevel(ctxt, where, title, Tkclient->Popup); 	d := chan of string;	tk->namechan(t, d, "d"); 	tkcmds(t, dialog_config);	cmd(t, ".top.msg configure -text '" + msg);	if (ico != nil)		cmd(t, ".top.ico configure -bitmap " + ico); 	n := len labs;	for(i := 0; i < n; i++) {		cmd(t, "button .bot.button" +				string(i) + " -command {send d " +				string(i) + "} -text '" + hd labs); 		if(i == dflt) {			cmd(t, "frame .bot.default -relief sunken -bd 1");			cmd(t, "pack .bot.default -side left -expand 1 -padx 10 -pady 8");			cmd(t, "pack .bot.button" + string i +				" -in .bot.default -side left -padx 10 -pady 8 -ipadx 8 -ipady 4");		}		else			cmd(t, "pack .bot.button" + string i +				" -side left -expand 1 -padx 10 -pady 10 -ipadx 8 -ipady 4");		labs = tl labs;	} 	if(dflt >= 0)		cmd(t, "bind . <Key-\n> {send d " + string dflt + "}"); 	e := cmd(t, "variable lasterror");	if(e != "") {		sys->fprint(sys->fildes(2), "Dialog error: %s\n", e);		return dflt;	}	tkclient->onscreen(t, nil);	tkclient->startinput(t, "kbd" :: "ptr" :: nil);	cmd(t, "update"); 	for(;;) alt {	c := <-t.ctxt.kbd =>		tk->keyboard(t, c);	p := <-t.ctxt.ptr =>		tk->pointer(t, *p);	c := <-t.ctxt.ctl or	c = <-t.wreq =>		tkclient->wmctl(t, c);	ans := <-d =>		return int ans;	tcs := <-tc =>		if(tcs == "exit")			return dflt;		tkclient->wmctl(t, tcs);	} } getstring_config := array[] of {	"label .lab",	"entry .ent -relief sunken -bd 2 -width 200",	"pack .lab .ent -side left",	"bind .ent <Key-\n> {send f 1}",	"focus .ent"}; getstring(ctxt: ref Draw->Context, parent: ref Draw->Image, msg: string): string{	where := localgeom(parent);	(t, wmctl) := tkclient->toplevel(ctxt, where + " -borderwidth 2 -relief raised", nil, Tkclient->Popup);	f := chan of string;	tk->namechan(t, f, "f"); 	tkcmds(t, getstring_config);	cmd(t, ".lab configure -text '" + msg + ":   ");	tkclient->onscreen(t, nil);	tkclient->startinput(t, "kbd" :: "ptr" :: nil); 	e := tk->cmd(t, "variable lasterror");	if(e != "") {		sys->print("getstring error: %s\n", e);		return "";	}	cmd(t, "update"); 	for(;;)alt{	c := <-t.ctxt.kbd =>		tk->keyboard(t, c);	p := <-t.ctxt.ptr =>		tk->pointer(t, *p);	c := <-t.ctxt.ctl or	c = <-wmctl =>		if(c == "exit")			return nil;		tkclient->wmctl(t, c);	<-f =>		return tk->cmd(t, ".ent get");	}}Showtk: con 0; cmd(top: ref Tk->Toplevel, s: string): string{	if (Showtk)		sys->print("%s\n", s);	e := tk->cmd(top, s);	if (e != nil && e[0] == '!')		sys->fprint(sys->fildes(2), "Dialog: tk error %s on '%s'\n", e, s);	return e;}