How to initialize a ref seq type

[solomonthewise]

building a lisp. the code was as follows.
    
    
     MalType* = object
        case mk*: Mk
        of mklist: lis*: seq[MalType]
        of mkint: intval: int
        of mkstring: strval: string
        of mkfloat: floatval: float
        of mkbool: boolval: bool
    
    Run

because of the recursive nature I thought ref type would be more efficient here