Lexical CATCH and named constructs

[Quux <QUUX at MIT-AI>]

Maybe do it with various kinds of parentheses:

	[SETQ X {CAR (IF [OR (CAR X)
			     (AND (CDR X) (RETURN-FROM "[" 3))
			     (RETURN-FROM "{" 5)]
			 [RETURN-FROM "[" 6]
			 LOSER)}]

Of course, you'd need a lot of different parentheses in general.
Maybe Carl has some ideas about this.

(This idea inspired by super-brackets -- use brackets to convey
control, not just textual, "closing off".)