## simple adt that operates on whitespace separated config files# such as /services/webget/config#CfgFile: module{	PATH: con	"/dis/lib/cfgfile.dis";	ConfigFile: adt	{		getcfg:	fn(me: self ref ConfigFile,field:string):list of string;		setcfg:	fn(me: self ref ConfigFile,field:string,val:string);		delete:	fn(me: self ref ConfigFile,field:string);		flush:	fn(me: self ref ConfigFile): string; 		 # ----- private ------		lines:	list of string;		file:	string;		readonly:	int;	}; 	init:	fn(file:string):ref ConfigFile;	verify:	fn(defaultpath: string, path: string) :ref Sys->FD;};