perl -MDevel::Peek -wle 'Dump(1); Dump(!!1)'
SV = IV(0x56346851ef48) at 0x56346851ef58
  REFCNT = 1
  FLAGS = (IOK,READONLY,PROTECT,pIOK)
  IV = 1
SV = PVNV(0x5634684f6050) at 0x5634684f43c8
  REFCNT = 2147483644
  FLAGS = (IOK,NOK,POK,READONLY,PROTECT,pIOK,pNOK,pPOK)
  IV = 1
  NV = 1
  PV = 0x563467d5e282 "1"
  CUR = 1
  LEN = 0