::= network = assets : facts : . ::= ; | ::= ; | ::= quality : , ; | topology : , ; ::= ::= [A-Za-z][A-Za-z0-9_]* ::= | ::= [A-Za-z0-9_]* ::= [1-9][0-9]* ::= | ::= = | := ::= < | > | <= | >= ::= -> | <-> ::= " " | \t | \n