BEGIN
	CLASS Fibonacci;
		HIDDEN fn, main;					! private members;
	BEGIN
		INTEGER fn;							! communication;

		PROCEDURE main;						! mimic uC++ coroutine main;
		BEGIN
			INTEGER fn1, fn2;

			fn := 0; fn1 := fn;
			Detach;							! suspend();
			fn := 1; fn2 := fn1; fn1 := fn;
			Detach;							! suspend();
			WHILE TRUE DO BEGIN
				fn := fn1 + fn2; fn2 := fn1; fn1 := fn;
				Detach;						! suspend();
			END;
		END;

		INTEGER PROCEDURE next;
		BEGIN
			Call( THIS Fibonacci );			! resume();
			next := fn;
		END;
		! Fibonacci constructor code;
		Detach;								! return to declaration;
		main;								! call main as last line of constructor;
	END Fibonacci;
	! program main equivalent;
	REF(Fibonacci) f1, f2;					! objects are references;
	INTEGER i;

	f1 :- NEW Fibonacci;
	f2 :- NEW Fibonacci;
	FOR i := 1 STEP 1 UNTIL 10 DO BEGIN
		OutInt( f1.next, 3 );
		OutText( " " );
		OutInt( f2.next, 3 );
		OutImage;
	END
END;

! Local Variables: ;
! tab-width: 4 ;
! compile-command: "cim Fib.sim" ;
! End: ;