poor mans ADT?

gistfile1.nim

#----------------------------------------------------
# ADT
#----------------------------------------------------

type
  SumT[T1,T2,T3,T4] = int

proc popFlags(x: int): int {.inline.} = x and 3

proc popPtr(x: int): int  {.inline.} =
  result = x and 0xFFFFFFFC'i32

proc getyp(s: SumT[T1,T2,T3,T4]): auto =
  var 
    f = s.popFlags
    p = s.popPtr
  if f == 0: return cast[ptr T1](p)[]
  if f == 1: return cast[ptr T2](p)[]
  if f == 2: return cast[ptr T3](p)[]
  if f == 3: return cast[ptr T4](p)[]

var val = 999.99
var typ: SumT[int,float,int,float] = cast[int](val.addr) and 1



echo(typ.getyp)