[DFDL-WG] Optional Initiator and Terminator?

[Garriss Jr., James P.]

Is there a way to specify that an initiator/terminator pair is optional?

IOW, these are both valid:

  { data }
  data

If not, which of these workarounds is better (and why)?

Choice
    DataWithInitiatorAndTeminator
   DataWithoutInitiatorAndTeminator

Or

Sequence
  OptionalInitiator (0 to 1)
  Data
  OptionalTerminator (0 to 1)

These seem the same to me, but maybe there's a reason why one is better.
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