event-handling approach to errors

[mwm at ucbtopaz.CC.Berkeley.ARPA]

>                                                            ...  How do
> you provide a correction action for something like a subscript violation?

Complain if the user doesn't catch it. The user then gets to use it for walking
dynamic arrays, to wit:

	i := 0
	while true do
		<mangle array element array[i]>
		end except when bounds: end

After seeing that a few times, it reads as naturally as:

	for (i = 0; i < bounds; i++)
		<mange array element array[i]> ;

	<mike