Due to this issue: https://issues.apache.org/jira/browse/DAFFODIL-1975
This is a non-backward-compatible change. The impact of it could be significant on existing schemas. Depending on scale of the impact we may have to put in flags to turn on/off the changed behavior. Love to avoid that, but the fixes to schemas that are broken by the DAFFODIL-1975 change are subtle - one must break up separated sequences into a nest of a few sequences, some separated, some not, to preserve current behavior of the schema. I am inclined to NOT fix this as part of the separator and separator suppression work currently in review as PR https://github.com/apache/incubator-daffodil/pull/88 <https://github.com/apache/incubator-daffodil/pull/88> Rather, my plan is to first commit functionality that is compatible with current Daffodil behavior, then have separate PRs for individual JIRA tickets that change behavior in non-backward-compatible ways like DAFFODIL-1975 does. This also helps isolate the tests that verify the change of behavior, which also serve as a start at tutorial material for explaining the required changes in existing DFDL schemas that use separated sequences. There are a number of clarifications in discussion on the DFDL Workgroup mailing list about behavior of sequences both separated and not, for parsing and unparsing. In some cases these, like DAFFODIL-1975, may be backwards incompatible. Several of those could be combined into one commit/PR, but in general they should be isolated from other changes if non-backward compatible. Any discussion?
