Regex: module { 	PATH:	con "/dis/lib/regex.dis"; # normally imported identifiers 	Re: type ref Arena;	compile:	fn(nil:string,nil:int): (Re, string);	execute:	fn(nil:Re, nil:string): array of (int, int);	executese:	fn(nil:Re, nil:string, se: (int, int), bol: int, eol: int): array of (int, int); # internal identifiers, not normally imported 	ALT, CAT, DOT, SET, HAT, DOL, NUL, PCLO, CLO, OPT, LPN, RPN : con (1<<16)+iota; 	refRex : type int;	# used instead of ref Rex to avoid circularity 	Set: adt {				# character class		neg: int;			# 0 or 1		ascii : array of int;		# ascii members, bit array		unicode : list of (int,int);	# non-ascii char ranges	}; 	Rex: adt {		# node in parse of regex, or state of fsm		kind : int;	# kind of node: char or ALT, CAT, etc		left : refRex;	# left descendant		right : refRex;	# right descendant, or next state		set : ref Set;	# character class		pno : int;	}; 	Arena: adt {		# free store from which nodes are allocated		rex : array of Rex;				ptr : refRex;	# next available space		start : refRex;	# root of parse, or start of fsm		pno : int;	};};