GR: module{	PATH:	con "/dis/math/gr.dis"; 	OP: adt{		code, n: int;		x, y: array of real;		t: string;	}; 	open:	fn(ctxt: ref Draw->Context, title: string): ref Plot; 	Plot: adt{		bye:	fn(p: self ref Plot);		equalxy:fn(p: self ref Plot);		graph:	fn(p: self ref Plot, x, y: array of real);		paint: 	fn(p: self ref Plot, xlabel, xunit, ylabel, yunit: string);		pen:	fn(p: self ref Plot, nib: int);		text:	fn(p: self ref Plot, justify: int, s: string, x, y: real); 		op: list of OP;		xmin, xmax, ymin, ymax: real;		textsize: real;		t: ref Tk->Toplevel;		# window containing .fc.c canvas		titlechan: chan of string;	# Wm titlebar		canvaschan: chan of string;	# button clicks for measurements	}; 	# op code	GRAPH:		con 1;	TEXT:		con 2;	PEN:		con 3; 	# pen	CIRCLE:		con 101;	CROSS:		con 102;	SOLID:		con 103;	DASHED:		con 104;	INVIS:		con 105;	REFERENCE:	con 106;	DOTTED:		con 107; 	# text justify	LJUST:		con 8r00;	CENTER:		con 8r01;	RJUST:		con 8r02;	HIGH:		con 8r00;	MED:		con 8r10;	BASE:		con 8r20;	LOW:		con 8r30;	UP:		con 8r100;};