While `StoreKind` can be any of `StoreInt|StoreFloat|StoreString`, once it is
instantiated, it will stay that one. Instead you have two choices:
1\. derive from a common `Store` object:
type
Store = ref object of RootObj
dep: seq[Store]
req: seq[Store]
StoreInt = ref object of Store
val: int
StoreFloat = ref object of Store
val: float
StoreString = ref object of Store
val: string
2\. use object variants:
type
StoreKind = enum StoreInt, StoreFloat, StoreString
Store = ref object of RootObj
case kind: StoreKind
of StoreInt: intVal: int
of StoreFloat: floatVal: float
of StoreString: strVal: string
dep: seq[Store]
req: seq[Store]
var a = Store(kind: StoreInt, intVal : 5, dep: @[], req: @[])
