begin
comment record RSegment for line segment description;
	record RPoint (real xcoor, ycoor);
	record RSegment(reference(RPoint) PtA, PtB);
	
	real procedure SegmentLength(reference(RSegment) value rss);
	begin
		real l1, l2;
		l1 := xcoor(PtA(rss)) - xcoor(PtA(rss));
		l2 := ycoor(PtA(rss)) - ycoor(PtA(rss));
		write(l1, l2);
		comment sqrt(l1*l1 + l2*l2);
		0
	end;
	
	reference (RSegment) rs;
	real len;
	
	rs := RSegment( RPoint(0,0), RPoint(1,1));
	len := SegmentLength(rs);
	write(len);
	
end.