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nasa / EdsLib

CCSDS SOIS Electronic Data Sheet Tool and Library
Apache License 2.0
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Add Alias Type element #55

Closed jphickey closed 9 months ago

jphickey commented 1 year ago

Is your feature request related to a problem? Please describe. In order to provide a migration/compatibility path when declarations need to move between packages, a "typedef" or alias type is required.

Describe the solution you'd like Support a new XML element AliasType that allows the same type to be referenced by multiple names. This allows the underlying type to be updated without breaking existing refs in other packages.

Describe alternatives you've considered

  1. SubRangeType (with the full range) could do something similar only works for numeric types
  2. A ContainerDataType with a single entry of the underlying type works as far as the binary structure goes (containers don't add any bits themselves, so its transparent in the binary representation) but this still affects the logical structure; scripts or symbolic refs to this element in other EDS-based files or tools need to include this extra layer of encapsulation.

Additional context The direct alias type is simpler and should solve the limitations of the alternatives

Requester Info Joseph Hickey, Vantage Systems, Inc.